1989_TI_Linear_Circuits_Vol_3_Voltage_Regulators_and_Supervisors 1989 TI Linear Circuits Vol 3 Voltage Regulators And Supervisors

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"TEXAS
INSTRUMENTS

Linear Circuits
Voltage Regulators and Supervisors

1989

1989

Linear Products

General Information

~_D_at_a_S_h_e_e_t_s__________________e~

~1

p_ro_d_u_c_t_p_r_e_v_ie_w_s______________~F_lII

__

~_D_e_S_ig_n_C__O_ns_i_d_e_ra_t_io_n_s__________~i_~tII

'1II

~_M_e_C_h_a_ni_c_a_I_D_at_a________________

Linear Circuits
Data Book
1989
Volume 3
Voltage Regulators and Supervisors

~

TEXAS
INSTRUMENTS

IMPORTANT NOTICE
Texas Instruments (TI) reserves the right to make changes to or to
discontinue any semiconductor product or service identified in this
publication without notice. TI advises its customers to obtain the latest
version of the relevant information to verify, before placing orders,
that the information being relied upon is current.
TI warrants performance of its semiconductor products to current
specifications in accordance with TI's standard warranty. Testing and
other quality control techniques are utilized to the extent TI deems
necessary to support this warranty. Unless mandated by government
requirements, specific testing of all parameters of each device is not
necessarily performed.
TI assumes no liability for TI applications assistance, customer product
design, software performance, or infringement of patents or services
described herein. Nor does TI warrant or represent that any license,
either express or implied, is granted under any patent right, copyright,
mask work right, or other intellectual property right of TI covering or
relating to any combination, machine, or process in which such
semiconductor products or services might be or are used.
Information contained in this data book supersedes all data for this
technology published by TI in the United States of America before
January 1989.

Copyright © 1989, Texas Instruments Incorporated

INTRODUCTION
Texas Instruments offers an extensive line of industry-standard integrated circuits designed to provide highlyreliable power supply controllers and regulators, voltage references, and voltage converters for system operations.
TI voltage regulators and supervisory circuits represent processes from standard bipolar through BIDFETt and
Schottky technologies.
This data book (Volume 3 of 3) provides information on the following types of products:
•
•
•
•
•
•

Supervisory circuits
Switched-capacitance voltage converters
Shunt voltage regulators and voltage references
Adjustable series-pass voltage regulators
Switching power supply and pulse-width-modulated (PWM) controllers and regulators
Fixed output series-pass voltage regulators (positive and negative)

These products provide critical functions for power conversion in analog and digital systems that:
• Utilize a wide range of voltages
• Require a constant output voltage regardless of changes in input voltage, output current, and ambient
temperature
• Demand high input-output isolation where analog circuitry must be connected independent of digital
ground
• Need low-voltage (battery) regulation.
New surface-mount packages (8 to 20 leads) include plastic chip carriers and the small-outline (D) plastic packages
that optimize board density with minimum impact on power-dissipation capability. Test equipment with handlers
and automated assembly bonders strengthens the production capabilities to provide a lower cost-to-performance
ratio. TI continues to enhance quality and reliability of integrated circuits by improving materials, processes,
test methods, and test equipment. In addition, specifications and programs are continuously updated. Quality
and performance are monitored throughout all phases of manufacturing.
The alphanumeric listing in this data book includes all devices in Volumes 1, 2, and 3. Products in this data
book are shown in bold type. The alphanumeric index provides a method of quickly locating the correct device
type. The selection guide includes a functional description of each device providing key parameter information
and packaging types. Ordering information and mechanical data are in the last section of the data book.
While this volume offers design and specification data only for voltage regulators and supervisory circuit
components, complete technical data for any TI semiconductor product is available from your nearest TI Field
Sales Office, local authorized TI distributor, or by writing directly to:
Texas Instruments Incorporated
LITERATURE RESPONSE CENTER
P.O. Box 809066
Dallas, Texas 75380-9066
We sincerely feel that the new 1989 Voltage Regulators and Supervisors data book will be a significant addition
to your library of technical literature from Texas Instruments.

tBIDFET-Bipolar. double-diffused, N-channel and P·channel MOS transistors on the same chip - Patented Process

v

vi

General Information

1-1

Contents
Page
Alphanumeric Index . . .
Selection Guide . . . . . .
Cross-Reference Guide.
Glossary . . . . . . . . . . .

1-2

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..
..
..
..

1-3
1-7
1-13
1-15

ALPHANUMERIC INDEX

AD7524 ............
AD7528 ............
AD7533 ...........
AD7628 ............
ADC0803 ..........
ADC0804 .......... .
ADC0805 ...........
ADC0808 ..........
ADC0808M . . . . . . . . . .
ADC0809 .......... .
ADC0820B
ADC0820C .........
ADC0831A
ADC0831B ......... .
ADC0832A .........
ADC0832B ......... .
ADC0834A .........
ADC0834B ......... .
ADC0838A .........
ADC0838B .... , .....
ICL7135 ........... .
,
LF198
LF347 , ........... ,
LF351 . , ......... , .
LF353 ............ ,
LF398
"
..........
LF411C ........... .
LF412C ...........
LM101A ...... , .... ,
LM107
LM108 · . . . . . . . . . . .
LM111 ....... , .....
LM124 ....... , .....
LM139 ............
LM148 ............
LM158 ............
LM185-2.5 ........•.
LM193 .............
LM201A ...........
LM207 ............ .
LM211 · . . . . . . . . . . .
LM217
LM218 ............ .
LM224 · . . . . . . . . . . .
LM237
LM239 ............
LM248 ............
LM258 ............
, .........
LM293
LM301A
LM307 ............
, .........
LM308
LM311 .............
LM317
LM318 ............
LM324 ............
LM330-5
LM337

.
.
.

......... .
.
......... .
.
.
.

........... .
.

.
............ .
.
.
.
.
.

.

............
.

............

.
.
.
...
........... .
.
...

........... .
.
.

.......... .
........... .

VOL2
VOL2
VOL2
VOL 2
VOL2
VOL2
VOL 2
VOL2
VOL2
VOL 2
VOL2
VOL 2
VOL2
VOL2
VOL2
VOL2
VOL2
VOL2
VOL2
VOL2
VOL 2
VOL 1
VOL 1
VOL 1
VOL 1
VOL 1
VOL 1
VOL 1
VOL 1
VOL 1
VOL 1
VOL 1
VOL 1
VOL 1
VOL 1
VOL 1
2-3
VOL 1
VOL 1
VOL 1
VOL 1
2-9
VOL 1
VOL 1
2-17
VOL 1
VOL 1
VOL 1
VOL 1
VOL 1
VOL 1
VOL 1
VOL 1
2-9
VOL 1
VOL 1
2-21
2-17

.

LM339 ............
LM348 ............ .
LM358 .. ...........
LM385-2.5 ..........
LM393 . . . . . . . . . . . .
LM2900 ...........
LM2901 . . . . . . . . . . .
LM2902 ...........
LM2903 ........... .
LM2904 ........... .
LM2907 ............
LM2917 ............
LM2930-5
LM2930-8
LM2931-5AQ
LM3302 ............
LM3900 ...........
LP111 . . . . . . . . . . . .
LP211 ........ , ....
LP239 ............ .
LP311 ............ .
LP339 ............ .
LP2901 ........... .
LT1001 ............
LT1004
LT1007 . . . . . . . . . . . . .
LT1008 . . . . . . . . . . . . .
LT1009
LT1011 ............
LT1012 . . . . . . . . . . . . .
LT1013 . . . . . . . . . . . . .
LT1016 . . . . . . . . . . . . .
LT1028 . . . . . . . . . . . . .
LT1036M ...........
LT1036C
LT1037 . . . . . . . . . . . . .
LT1054
LT1070
LT1084
LTC1044
LTC 1052 ..........
LTC7652 ..........
MC1445 ............
MC1458 ............
MC1558 ...........
MC3303 ...........
MC3403 ...........
MC3423
MC3470 ...........
MC34060 ...........
MC79L05 ...........
MC79L05A
MC79L12 ...........
MC79L12A
MC79L15 ..•........
MC79L15A
MF4A-50 . ..........
MF4A-100 . . . . . . . . . . .
'

.

.
.

.

..........
..........
........
.

.

.

............
............

.

.......... .
............
............
............
...........
.
.

.

.
.
.......... .
.

.........

.........

........ .

VOL 1
VOL 1
VOL 1
2-3
VOL 1
VOL 1
VOL 1
VOL 1
VOL 1
VOL 1
VOL 1
VOL 1
2-29
2-29
2-37
VOL 1
VOL 1
VOL 1
VOL 1
VOL 1
VOL 1
VOL 1
VOL 1
VOL 1
2-39
VOL 1
VOL 1
2-51
VOL 1
VOL 1
VOL 1
VOL 1
VOL 1
3-3
3-3
VOL 1
3-5
3-9
3-11
2-59
VOL 1
VOL 1
VOL 1
VOL 1
VOL 1
VOL 1
VOL 1
2-75
VOL 1
2-81
2-77
2-77
2-77
2-77
2-77
2-77
VOL 2
VOL 2

TEXAS ."

INSTRUMENTS
POST OFFICE BOX 655012 • DALLAS, TEXAS 75285

MF10A . ............
MF10C ............
NE555 · . . . . . . . . . . .
NE556 · . . . . . . . . . . . .
NE592 .............
NE5532 ............
NE5534 · . . . . . . . . . .
OP07 ..............
OP07C .............
OP07D ............
OP07E .
OP27A . ............
OP27C .
OP27E . ............
OP27G .............
OP37A . ............
OP37C .............
OP37E . ............
OP37G · . . . . . . . . . . .
, ..
RC4136
RC4558 · . . . . . . . . . . .
RC4559
RM4136 ............
RM4558 ............
RV4136
...........
RV4558 ............
SA555 .............
......... ,
SA556
,
,
SE555
SE555C · . . . . . . . . . .
SE556 .,., .........
SE556C ............
SE592 .............
SE5534 ............
SG2524
SG3524
SN28827 . ..........
SN28828 . . . . . . . . . .
SN76494/A . .......
SN76496/A .........
TL0101 .............
TL010C . ...........
TL011 . . . . . . . . . . . . .
TL012 . . . . . . . . . . . . . .
TL014A . . . . . . . . . . . . .
TL021 ..............
TL022M ............
TL022C ............
TL026C ............
TL027C ............
TL031 ..............
TL032 . . . . . . . . . . . . . .
TL034 . . . . . . . . . . . . . .
TL040C
...........
TL041C ............
TL044M ............
TL044C ............
TL051 ..............

.

.

.

.
............
............

.
.........
............
.

.
·.
... ..... . · .
.

............
............
.

·.

.

.

.

VOL2
VOL2
VOL1
VOL 1
VOL 1
VOL 1
VOL1
VOL1
VOL1
VOL 1
VOL 1
VOL 1
VOL 1
VOL 1
VOL 1
VOL 1
VOL 1
VOL1
VOL 1
VOL 1
VOL 1
VOL1
VOL 1
VOL 1
VOL 1
VOL 1
VOL1
VOL1
VOL1
VOL 1
VOL 1
VOL1
VOL 1
VOL1
2-89
2-89
VOL 1
VOL1
VOL 1
VOL1
VOL 1
VOL 1
VOL 1
VOL 1
VOL 1
VOL 1
VOL 1
VOL 1
VOL 1
VOL 1
VOL 1
VOL 1
VOL1
VOL 1
VOL 1
VOL 1
VOL 1
VOL 1

C

0

"+=
CO

..E
-ca..

0

C

II)

C

II)

0

1-3

ALPHANUMERIC INDEX

TL052 ............ .
TL054 ............ .
TL060 .............
TL061 ............ .
TL062 ............ .
G) TL064 ............ .
CD TL066M ........... .
:::::I TL0661 ............ .
CD
TL066C . ...........
!!. TL070 . ,'., ..........
TL071 .............
S" TL072 ............ .
0 TL074 ............ .
TL075 ............ .
3 TL080 .............
AI TL081 ............ .
....
C)" TL082 .............
:::::I TL083 ............ .
TL084 ............ .
TL085 .............
TL087 .............
TL088 ............ .
TL0808 ........... .
TL0809 ........... .
TL136C ........... .
TL170C ........... .
TL172C ........... .
TL1731 .............
TL173C ........... .
TL182 ............ .
TL185 ............ .
TL188 ............ .
TL191 ............ .
TL287 ............ .
TL288 ............ .

..
......

TL317M ........... .
TL317C ............

TL321 1 ............ .
TL321C ........... .
TL3221 ............ .
TL322C ........... .
TL331 1 ............ .
TL331C ........... .

............
...........

2·101
2·101

VOL 1
VOL 1
VOL 1
VOL 1
VOL 1
VOL 1

TL4301
TL430C .......... ..
TL431AI
TL431AC .......... .
TL431M ........... .
TL431 I
TL431C ............

2·107
2·107
2·111
2·111
2·111
2·111
2·111

TL493 .............
TL494 .............
TL495 .............
TL496C .........••.
TL497AM
TL497AI
TL497AC ....•..... .

2·123
2·123
2·123
2·131
2·135
2·135
2·135

............

TL441 AM ..........

. VOL 1

......... .
...........

1-4

VOL 1
VOL 1
VOL 1
VOL 1
VOL 1
VOL 1
VOL 1
VOL 1
VOL 1
VOL1
VOL 1
VOL 1
VOL 1
VOL1
VOL 1
VOL 1
VOL 1
VOL 1
VOL 1
VOL 1
VOL 1
VOL 1
VOL 2
VOL 2
VOL 1
VOL 1
VOL 1
VOL 1
VOL 1
VOL 2
VOL 2
VOL2
VOL2
VOL 1
VOL1

TL499A

............

3·13

TL500 . ............
TL501 . ............
TL502 ., ...........
TL503 . ............
TL505 .............
TL507 . ............
TL514M ........... .
TL592 ............ .
TL592B . ...........

VOL 2
VOL 2
VOL 2
VOL2
VOL2
VOL2
VOL 1
VOL 1
VOL 1

............
............

2·143
2·143
2·143
2·153

TL5941 ............ .
TL594C
TL595C
TL59S

.............

TL601 ............ .
TL604 . ............
TL607 ............ .
TL61 0 .............
TL712 .............
TL714C ........... .
TL721 ............ .

..........
..........

TL750L05
TL750LOS
TL750L10
TL750L12
TL750M05 ..........
TL750MOS ..........
TL750M10 ..........
TL750M12 ..........
TL751L05
TL751 LOS
TL751L10
TL751L12
TL751M05 ....•.....
TL751MOS ..........
TL751M10 ...•......
TL751M12 ...•.•....
TL7S0·05 .........•.
TL7S0·12 ...........
TL7S0·15 ...........
TL7S3C .•..........

..........
..........
..........
..........
..........
..........

VOL2
VOL2
VOL2
VOL2
VOL1
VOL 1
VOL1
2·159
2·159
2·159
2·159
2·163
2·163
2·163
2·163
2·159
2·159
2·159
2·159
2·163
2·163
2·163
2·163
2·169
2·169
2·169
2·173

TL851 ............ . VOL1
TL852 ............ . VOL 1
TL853 ............ . VOL 1
TL1451AC ..........

2·185

TL3013C .......... .
TL3019C .......... .
TL3020C .......... .
TL31011 ........... .
TL3101C .......... .
TL31 031 ........... .
TL3103C .......... .
TL5501 .............
TL5601 .............
TL5602 .............

VOL 1
VOL 1
VOL 1
VOL 1
VOL 1
VOL 1
VOL 1
VOL2
VOL 2
VOL 2

TL7702A
TL7705A
TL7709A

2·191
2·191
2·191

...........
...........
...........

TEXAS ."

INSTRUMENlS
POST OFFICE BOX 655012 • DALLAS, TEXAS 75265

. ..........
...........
..........
..........

TL7712A
TL7715A
TL7770·5 .....••....
TL7770·12
TL7770·15
TL77S0·5 .........•.
TL77S0·12
TL77S0·15

..........

..........

TLC04 . ............
TLC0820A ...........
TLC0820B ...........
TLC10 . ............
TLC14 . ............
TLC20 . ............
TLC251C . ..........
TLC252C . ..........
TLC254C . ..........
TLC25L2C ...........
TLC25L4C ...........
TLC25M2C . .........
TLC25M4C . .........
TLC271 . ...........
TLC272 . ...........
TLC274 . ...........
TLC277 . ...........
TLC279 ............
TLC27L2 ............
TLC27L4 ............
TLC27L7 ............
TLC27L9 ............
TLC27M2 . ..........
TLC27M4 . ..........
TLC27M7 . ..........
TLC27M9 ...........
TLC339M . ..........
TLC3391 ............
TLC339C ...........
TLC352M . ..........
TLC3521 . ...........
TLC352C . ..........
TLC354M ...........
TLC3541 ............
TLC354C ...........
TLC372M . ..........
TLC3721 ., ..........
TLC372C . ..........
TLC374M ...........
TLC3741 . ...........
TLC374C . ..........
TLC393M . ..........
TLC3931 ............
TLC393C . ..........
TLC532A . ..........
TLC533A . ..........
TLC540 . ...........
TLC541 . ...........
TLC542 . ...........
TLC543 . ...........

2·191
2·191
2·199
2·199
2·199
2·205
2·205
2·205

VOL 2
VOL 2
VOL2
VOL2
VOL2
VOL 2
VOL 1
VOL 1
VOL 1
VOL1
VOL1
VOL1
VOL 1
VOL 1
VOL 1
VOL 1
VOL 1
VOL 1
VOL 1
VOL 1
VOL 1
VOL 1
VOL 1
VOL 1
VOL 1
VOL 1
VOL 1
VOL 1
VOL 1
VOL 1
VOL1
VOL1
VOL 1
VOL1
VOL 1
VOL1
VOL 1
VOL 1
VOL 1
VOL 1
VOL 1
VOL 1
VOL1
VOL1
VOL2
VOL 2
VOL 2
VOL 2
VOL 2
VOL2

ALPHANUMERIC INDEX

TLC544 . . . . . . . . . . . .
TLC545 ........... .
TLC546 ........... .
TLC548 ........... .
TLC549 ........... .
TLC551C .......... .
TLC552C .......... .
TLC555M .......... .
TLC5551 ............
TLC555C .......... .
TLC556M .......... .
TLC5561 ............
TLC556C .......... .
TLC1078 .......... .
TLC1079 .......... .
TLC1225A ..........
TLC1225B ......... .
TLC1540 ...........
TLC1541 ...........
TLC2201 ...........
TLC2652 ...........
TLC2654 ...........
TLC3702M ..........
TLC37021 .......... .
TLC3702C ......... .
TLC3704M ..........
TLC37041 ...........
TLC3704C ......... .
TLC4016 .......... .
TLC4066 ...........
TLC5502 ...........
TLC5602 ...........
TLC7135 .......... .
TLC7524 .......... .
TLC7528 .......... .
TLC7533 .......... .

VOL 2
VOL 2
VOL 2
VOL2
VOL2
VOL 1
VOL 1
VOL 1
VOL1
VOL 1
VOL 1
VOL 1
VOL 1
VOL 1
VOL 1
VOL2
VOL 2
VOL 2
VOL2
VOL 1
VOL 1
VOL 1
VOL 1
VOL 1
VOL 1
VOL 1
VOL 1
VOL 1
VOL2
VOL 2
VOL 2
VOL 2
VOL 2
VOL 2
VOL 2
VOL 2

TLC77011
TLC77051
TLC7721I
TLC77251

3·15
3·15
3·15
3·15

..........

......... .
......... .
..........

TLC32040 ......... .
TLC32041 ......... .
TLC32042 ......... .
TLC32044 ......... .
TLC32045 ......... .
TLE2021 .......... .
TLE2022 .......... .
TLE2024 .......... .
uA709M ........... .
uA709C ........... .

VOL2
VOL2
VOL 2
VOL 2
VOL 2
VOL 1
VOL 1
VOL 1
VOL 1
VOL 1

uA723M
uA723C .. ..........

2·211
2·211

uA733M
uA733C
uA741M
uA741C
uA747M
uA747C

VOL 1
VOL 1
VOL 1
VOL 1
VOL 1
VOL 1

...........

........... .
........... .
........... .
........... .
........... .
........... .

uA748C ............ VOL 1
uA2240C . .......... VOL 1

............
........... .

uA7805
uA7806
uA7808
uA781 0
uA7812
uA7815
uA7818
uA7824
uA7885
uA78L02AC •...•.•..
uA78L02C .....•.•..
uA78L05AC •........
uA78L05C
uA78L06AC ......•..
uA78L06C
uA78L08AC •...•••.•
uA78L08C ..•..•.•..
uA78L09AC .....••..
uA78L09C ..........
uA78L10AC ....•....
uA78L10C ..•...••..
uA78L12AC ....•.•.•
uA78L12C
uA78L15AC ......•..
uA78L15C •.........
uA78M05M
uA78M05C
uA78M06 •.••...... .
uA78M08 •..•....•. .
uA78M09 .•.•...•.. .
uA78M10 ..•.•..... .
uA78M12M
uA78M12C
uA78M15M
uA78M15C
uA78M20 ..•....... .
uA78M24 .......... .
uA7905
uA7906
uA7908
uA7912
uA7915
uA7918
uA7924
uA7952
uA79M05M
uA79M05C
uA79M06M
uA79M06C
uA79M08M
uA79M08C
uA79M012M
uA79M012C
uA79M015M
uA79M015C
uA79M20C

........... .
............
...........
.
........... .
........... .
........... .

............

......... .

..........

..........
.........
.........

.........
.........
..........
........

. ...........
............
............
............
............
............
............
............
.........
.........
.........
.........
.........
.........
........

........
........
........
.........

2-221
2-221
2·221
2-221
2·221
2-221
2-221
2·221
2·221
2·229
2·229
2·229
2-229
2-229
2·229
2·229
2·229
2·229
2·229
2·229
2·229
2·229
2·229
2·229
2·229
2·237
2·237
2·237
2·237
2·237
2·237
2·237
2·237
2·237
2·237
2·237
2·237
2·247
2·247
2·247
2·247
2·247
2·247
2·247
2·247
2·253
2·253
2·253
2·253
2·253
2·253
2·253
2·253
2·253
2·253
2·253

TEXAS ",

INSTRUMENTS
POST OFFICE BOX 655012 • OALLAS. TEXAS 75265

uA79M24C ......... .
UC1846 ............
UC1847 . ...........
UC2842 ............
UC2843 ............
UC2844 .......•....
UC2845 ............
UC2846 ............
UC2847 ............
UC3842
UC3843 . ...........
UC3844 .....•......
UC3845 ............
UC3846 ............
UC3847 ........... .
•••

••••••

0

••

2-253
2-263
2-263
3·21
3·21
3·21
3·21
2·263
2·263
3·21
3·21
3·21
3·21
2·263
2·263

C

0
+i

CO

E
...

....0
16
...

.5

Q)

C

Q)

~

1-5

G')
CD

..
5"
....
3
:::I

CD

!.
o

....
III

o·:::I

1-6

VOLTAGE REGULATORS AND SUPERVISORS
SELECTION GUIDE
power supply supervisors

FUNCTION

(Values specified for T A

SENSE

SENSE

INPUT

INPUT

SUPPLY

THRESHOLD
TOLERANCE

TYPE

OUTPUT

1 VSU

2VSU

*

-

2.6

*

2.53

TL7702A

4.55

TL7705A

15 V

-

*

-

1.2

1

5V

-

4.55

1

5V

*
*
*
*
*
*

Monitor

5V

Undervoltage

9V

Monitor

12 V

CMOS
Undervoltage
Monitor

CMOS
Undervoltage

12 V

Monitor

15 V
5V

Dual

Undervoltage

12 V

IOvervoltage *

15 V

25 DC)

PAGE

PACKAGE

THRESHOLD
(V TYP)

Overvoltage

=

NO.

(%)

5

7.6

1

Open-Emitter

Open-Collector

TL7712A

13.5

TL7715A

Open-Drain

2-75

"';:;

ca

E

~

0, P

2-191

0, JG, P

3-15

TL7709A

10.8

c

o

0, JG, P

MC3423

o

c

TLC7701

Push-Pull

TLC7721

Open-Drain

TLC7705

Push-Pull

TLC7725

4.55

TL7780-5

10.9

1

Open-Collector

TL7780-12

13.64

0, N

2-205

OW, N

2-199

TL7780-15

4.55

TL7770-5

10.9

1

Open-Collector

TL7770-12

13.64

TL7770-15

* Programmable

switched-capacitor voltage converters
SUPPLY
CONTROL

OUTPUT

VOLTAGE

TOPOLOGY

SWITCH

RANGE
(V)

Voltage
Mode

Single

(Values specified for T A

QUIESCENT

MAXIMUM

MAXIMUM

CURRENT

CONTINUOUS

FREQUENCY

(NO LOAD)

lOUT

(kHz)

CONVERSION

50 rnA

10

95

LTC1044

150 ~A

300 rnA

35

90

LT1054

MAXIMUM

VOLTAGE

CURRENT TO

SHUNT

RANGE (V)

MAINTAIN REG

CURRENT

10 ~A

(%)

TEMPERATURE
COEFFICIENT
(TVP)

1

20 ~A

20 rnA

400 ~A

2
0.2

2.5 to 30

500

~A

(Typ)

2.5 to 36

270

~A

(Typ)

4
150 rnA

JG, L, P

(Values specified for T A
TOLERANCE

2
1

NO.

(%)

200 ~A

REGULATOR

PAGE

PACKAGE

TYPE

1.5-9

shunt voltage regulators/references

2.5 (Typ)

EFFICIENCY

3.5-15

MINIMUM SHUNT

25 D C)

TYPICAL

DEVICE
LT1004

20 PPM/oC

LM185-2.5
LM385-2.5

15 PPM/oC
120 PPM/oC
30 PPM/oC

TEXAS . "

INSTRUMENTS
POST OFFICE BOX 655012 • DALLAS, TeXAS 75265

PACKAGE
0, LD, LP
L

2-59

~

=

25 DC)

PAGE
NO.
2-39
2-3

0, LD, LP

~

TL430

LP

2-107

TL431

0, JG, LD, LP, P

LT1009

TL431A

D, LP, P

2-111

1-7

VOLTAGE REGULATORS AND SUPERVISORS
SELECTION GUIDE
adjustable series-pass voltage regulators
OUTPUT
VOLTAGE

G')
CD
::::I
CD

i-

....S"
o

..3

...o·

Postive Output

Negative Output
Positive or Negative

Output
Positive Output

100mA
750mA

OUTPUT
VOLTAGE
RANGE (VI
1.2 to 32
1.25 to 125

1.5 A

1.2 to 37

OUTPUT
CURRENT

1.5 A
150mA
5A

-1.2 to -37

(Values specified over operating temperature range)
TOLERANCE

(%1
'5
5

MAXIMUM
(VI-Vol
DIFFERENCE
35 V
125 V

5

40V

PACKAGE

TL317
TL783
LM217
LM317
LM237
LM337

D, JG, LP

KC

-40V

2 to 37

5

38V

uA723

D,J,N,U

3 to 28

2

30V

LT1084

KA,KK

::::I

TEXAS ."

INSTRUMENTS
POST OFFICE BOX 655012 • DALLAS, TEXAS 75265

PAGE
NO.
2-101

~

4

D)

1-8

DEVICE

2-9

2-17
2-211
3-11

VOLTAGE REGULATORS AND SUPERVISORS
SELECTION GUIDE
(Values specified for T A -

switching power supply controllers and regulators

25°C)

II
c

o

'+::

.
CO

-..
E
o
c

1ii

-

CI)

x

-

x
5

Voltage-Mode
Pulse-Width
Modulated
Controllers

-

1--+------1 X

250

300

X
X
X

-

Dual

1

-

X

-

-

2

X

X -

-

X

X

-

-

2

X

-

MC34060
TL493

2

-

-

TL494

D,N
D, J, N

2-81

C

CI)

2-123

c.?

_ ~X~~X~~X~-~~-~~2~_--+_--+~T~L4~9~5~~~N~~______~
SG2524
J, N
2-89
SG3524
TL594
2 X X X D,N
2-143
TL595
X
X X X 2 -

x

250

300

1

-

-

-

21

500

4

-

-

X

X

X

-

2

-

-

TL598

X

X

-

-

X

-

TL1451A

D, J, N

2-153

D, N

2-185

UC2842
UC2843
UC3842

X

-

X

± 1000

X -

500

-

X

-

X

Current Mode

Pulse-Width
Modulated
Controllers

UC3843

X

UC2844

X

UC2845

X
X

UC3844
UC3845

2-21
D,P
2-21

UC1846
UC1847

-

X

X

±1000

500

1

X

-

-

X

-

X -

UC2846
UC2847
UC3846

2-263

FN, N

UC3847

X
Fixed On-Time
Voltage Mode

-

X -

X
X

5000
1200
700

40

2

X

-

X

-

LT1070

KJ, KV

40

10

-

-

-

-

-

TL496
TL499A

D,P

5

-

5

-

-

-

-

TL497A

50

P
D, J, N

3-9
2-131
3-13
2-135

X Applicable data
- Non-applicable data

TEXAS " ,
INSTRUMENTS
POST OFFICE BOX 655012 • DALLAS, TEXAS 75265

1-9

VOLTAGE REGULATORS AND SUPERVISORS
SELECTION GUIDE
positive fixed output series-pass voltage regulators
(Values specified over operating temperature range)

G')
CD

OUTPUT
VOLTAGE
(V)

..
....5'o
..3

OUTPUT
CURRENT
RATING

~

CD

2.6

100 rnA

~

100 rnA

150mA

I»

r+

o·

5

OUTPUT
VOLTAGE
TOLERANCE
(±%)

5
10
5
5
10
5
10

MINIMUM
DIFFERENTIAL
VOLTAGE
(V)
2
0.6
2

0.6

5
500 rnA

~

750 rnA
1.5 A
500 rnA

6
6.2

100 rnA
1.5 A

2
1

0.6

2
5
10

2

5

100 rnA
10
150 rnA
8

0.6
5

500 rnA
750 rnA

8.5

1.5 A
100 rnA

9

500 rnA
100 rnA
10

150 rnA

2
1

5
10

Dual

1-10

I

5
12

100 rnA
3A

2

5
10
5

500 rnA

.1

0.6

0.6
2

4

2.2
3

TEXAS

TYPE

uA78L02A
uA78L02
uA78L05A
LM2931-5AQ
uA78L05
LM330
LM2930-5
TL750L05
TL751L05
uA78M05
TL750M05
TL751M05
TL780-05
uA7806
uA78M06
uA78L06A
uA78L06
uA7806
uA78L08A
uA78L08
LM2930-8
TL750L08
TL751L08
uA78M08
TL750M08
TL751M08
uA7808
uA7885
uA78L09A
uA78L09
uA78M09
uA78Ll0A
uA78Ll0
TL750Ll0
TL751Ll0
uA78Ml0
LT1036

-II

INSTRUMENlS
POST OFFICE BOX 655012 • DALLAS. TEXAS 75265

PACKAGE

PAGE
NO.

D. JG. LP

2-229

D, KC, LP
D, JG, LP
KC
KC, LP
D, KC, LP, P
D,P

2-37
2-229
2-21
2-29

JG,KC

2-237

2-159

2-163
KC

I 2-169
I 2-247
I 2-237

D, JG, LP

2-229

KC

2-247

D, JG, LP

2-229

KC, LP
D, KC, LP, P
D,P

2-29
2,159

KC

2-159
2-237
t--2-163

~
I 2-221

D, JG, LP

2-229

KC

2-237

D, JG, LP

2-229

D, KC, LP, P
D,P
KC

2-159
2-159
2-237

KJ, KV

3-3

VOLTAGE REGULATORS AND SUPERVISORS
SELECTION GUIDE
positive fixed output series-pass voltage regulators (continued)
(Values specified over operating temperature range)
OUTPUT

OUTPUT

VOLTAGE

CURRENT

(V)

RATING

10

750 mA
1.5 A
100mA
150 mA

12

OUTPUT

MINIMUM

VOLTAGE

DIFFERENTIAL

TOLERANCE

VOLTAGE

(±%)

(V)

1
5

5

1.5 A

2

0.6

0.6

2

15

500 mA

5
2

1.5 A

24

uA78L12A

500 mA

c

2-163

'';:;
CU

2-229

TL750L12

D, KC, LP, D

2-159

TL751L12
uA78M12

D,P

2-159
2-237

JG,KC

TL750M12
TL751M12

2-163
KC

T169
2-221

uA78L15A
uA78L15

D, JG, LP

2-229

uA78M15

JG,KC

2-237

uA7824

TEXAS •

INSTRUMENlS
POST OFFICE BOX 655012 • DALLAS, TEXAS 75265

o

......E
.5
..
o

'ii
Q)

C

Q)

o

2-169

TL780-15

uA78M20
uA78M24

1.5 A

NO.

D, JG, LP

uA7818
5

PAGE

2-221

~

uA7815

18
20

KC

uA7812

10
2

TL751Ml0

TL780-12

5
100 mA

TL750Ml0

uA78L12

2
1

PACKAGE

uA7810

10

500mA
750mA

0.6

TYPE

KC

- 2-247
2-237

2-221

1-11

VOLTAGE REGULATORS AND SUPERVISORS
SELECTION GUIDE
negative fixed output series-pass voltage regulators
(Values specified over operating temperature range)
OUTPUT

OUTPUT

VOLTAGE

CURRENT

(V)

RATING

100mA
5

5.2
6
8

500mA
1.5 A

18

24

1-12

VOLTAGE

(±%)

(V)

5
10

1.7

MC79L05A
MC79L05

D, LP

5

10
5
10

2
1.7

NO.
2·77

JG, KC

2·253
2·247

uA79M06

JG, KC

2·253

uA7906
uA79M08

KC
JG,KC

2·247
2·253

KC

2·247

D, LP

2·77

uA7908
1.7

PAGE

KC

uA7952
2

500 mA

MC79L12A
MC79L12
uA79M12
uA7912
MC79L15A
MC79L15
uA79M15

JG, KC

2·253

KC

2·247

0, LP

2·77

JG,KC

2·253

uA7915

1.5 A
5

1.5 A

PACKAGE

uA7905

500mA

500 mA

TYPE

uA79M05

500 mA
1.5 A

100 mA

20

TOLERANCE

1.5 A

1.5 A

15

MINIMUM
DIFFERENTIAL

500mA

100mA
12

OUTPUT
VOLTAGE

2

uA7918
uA79M20
uA79M24
uA7924

TEXAS ."

INSTRUMENTS
POST OFFICE BOX 655012 • DALLAS, TEXAS 75265

KC

-

2·247
2·253

2-247

VOLTAGE REGULATORS
CROSS· REFERENCE GUIDE
Replacements are based on similarity of electrical and mechanical characteristics as shown in currently published
data. Interchangeability in particular applications is not guaranteed. Before using a device as a substitute, the
user should compare the specifications of the substitute device with the specifications of the original.
Texas Instruments makes no warranty as to the information furnished and buyer assumes all risk in the use
thereof. No liability is assumed for damages resulting from the use of the information contained herein.
Manufacturers are arranged in alphabetical order.

c
o

',tj

ca

LINEAR
TECHNOLOGY

DIRECT
TI
REPLACEMENT

LM317
LM337
LM385-2.5
LTl 004-2. 5
LT1009
LTl036
LTl070
SG3524
UC3846
UC3847

LM317
LM337
LM385-2.5
LTlO04-2.5
LTlO09
LTl036
LTl070
SG3524
UC3846
UC3847

MOTOROLA

DIRECT
TI
REPLACEMENT

LM217. LM317
LM237, LM337
MC1723
MC3423
MC34060
MC78LOO Series
MC78MOO Series
MC79LOO Series
TL431
TL431A
TL494
TL495
TL780-5
TL780-12
TL780-15

II

NO.
2-9
2-17
2-3
2-39
2-51
3-3
3-9
2-89
2-263
2-263

LM217. LM317
LM237. LM337
UA723
MC3423
MC34060
uA78LOO Series
uA 78MOO Series
MC79LOO Series
TL431
TL431A
TL494
TL495
TL780-5
TL780-12
TL780-15

TEXAS ~

INSTRUMENTS
POST OFFICE BOX 655012 • DALLAS. TEXAS 75265

E

PAGE

~

o

.E

'ii
~

Q)

C

Q)

"

PAGE

NO.
2-9
2-17
2-211
2-75
2-81
2-229
2-237
2-77
2-111
2-111
2-123
2-123
2-169
2-169
2-169

1-13

VOLTAGE REGULATORS
CROSS·REFERENCE GUIDE
DIRECT
NATIONAL

G')
~

..
....5'
..3
:::l

~

e!.
0

I»

r+

O·

:::l

LM217, LM317
LM237, LM337
LM317L
LM330
LM336-2.5
LM385-2.5
LM723
LM2930-5
LM2930-8
LM2931-5
LM3524
LM7800 Series
LM78LOO Series
LM78MOO Series
LM7900 Series
LM79LOO Series
LM79MOO Series

SILICON
GENERAL
SG3524
SG3842/3/4/5

SPRAGUE
ULN8194
ULN8195

UNITRODE
TL431
UC317
UC337
UC494
UC494A
UC495
UC495A
UC2842/3/4/5
UC3842/3/4/5
UC3846/UC2846
UC384 7/UC284 7
UC7800 Series
UC7800A Series
UC7900 Series

1-14

TI
REPLACEMENT
LM217, LM317
LM237, LM337
TL317
LM330
LM385-2.5
uA723
LM2930-5
LM2930-8
LM2931-5A
SG3524
uA 7800 Series
uA 78LOO Series
uA 78MOO Series
uA 7900 Series
MC79LOO Series
uA 79MOO Series

SUGGESTED
TI
REPLACEMENT

LT1009
lT1004-2.5

DIRECT
TI
REPLACEMENT
SG3524
UC3842/3/4/5

2-9
2-17
2-101
2-21
2-51
2-39
2-211
2-29
2-29
2-37
2-89
2-221
2-229
2-237
2-247
2-77
2-253

PAGE
NO.
2-89
3-21

DIRECT
TI
REPLACEMENT
TL594
TL595
DIRECT
TI
REPLACEMENT
TL431
LM317
LM337
TL494
TL594
TL495
TL595
UC2842/3/4/5
UC3842/3/4/5
UC3846/UC2846
UC384 7/UC284 7
uA 7800 Series

PAGE
NO.

PAGE
NO.
2-143
2-143
SUGGESTED
TI
REPLACEMENT

TL 780-00 Series
uA 7900 Series

TEXAS •

INSTRUMENTS
POST OFFICE BOX 855012 • DALLAS, TEXA~ 75266

PAGE
NO.
2-111
2-9
2-17
2-123
2-143
2-123
3-143
3-21
3-21
2-263
2-263
2-221
2-169
2-247

GLOSSARY
VOLTAGE-REGULATOR TERMS AND DEFINITIONS

SERIES REGULATORS
Bias Current
The difference between input and output currents.
NOTE: This is sometimes referred to as quiescent current.

II
c

o

',j:

Current-Limit Sense-Voltage
The voltage that is a function of the load current and is normally used for control of the current-limiting
circuitry. This is the current-sense voltage at which current limiting occurs.
Dropout Voltage

'"..E

....o

.5

The low input-to-output differential voltage at which the circuit ceases to regulate against further reductions
in input voltage.

..

10
C1)

C

Feedback Sense Voltage

C1)

The voltage that is a function of the output voltage and is used for feedback control of the regulator.

o

Input Regulation
The change in output voltage, often expressed as a percentage of output voltage, for a change in input
voltage from one level to another level.
.
NOTE: Sometimes this characteristic is normalized with respect to the input voltage change.
Output Noise Voltage
The rms output noise voltage, sometimes expressed as a percentage of the dc output voltage, with constant
load and no input ripple.
Output Regulation
The change in output voltage, often expressed as a percentage of output voltage, for a change in load
current from one level to another level.
Output Voltage Change with Temperature
The percentage change in the output voltage for a change in temperature. This is the net change over
the total temperature range.
Output Voltage Long-Term Drift
The change in output voltage over a long period of time.
Peak Output Current
The maximum output current that can be obtained from the regulator due to limiting circuitry within the
regulator.
Reference Voltage
The voltage that is compared with the feedback sense voltage to control the regulator.
Ripple Rejection
The ratio of the peak-to-peak input ripple voltage to the peak-to-peak output ripple voltage.
NOTE: This is the reciprocal of ripple sensitivity.

TEXAS " ,
INSTRUMENlS
POST OFFICE BOX 655012 • DALLAS. TEXAS 75265

1-15

GLOSSARY
VOLTAGE·REGULATOR TERMS AND DEFINITIONS
Ripple Sensitivity
The ratio of the peak-to-peak output ripple voltage, sometimes expressed as a percentage of output voltage,
to the peak-to-peak input ripple voltage.
NOTE: This is the reciprocal of ripple rejection.

c;)
CD

..
cr..
3

Short-Circuit Output Current

::::I

The output current of the regulator with the output shorted to ground.

CD

e!.

Standby Current
The input current drawn by the regulator with no output load and no reference voltage load.

::::I

Temperature Coefficient of Output Voltage (avol

m

r+

o·::::I

1-16

The ratio of the change in output voltage, usually expressed as a percentage of output voltage, to the
change in temperature. This is the average value for the total temperature change.
aVO

=

±

[ Va

at T2 - Va at T1] ~ 100% ]
Va at 25°C
T2 - T1

TEXAS ."

INSTRUMENlS
POST OFFICE BOX 665012 • DALLAS, TEXAS 75285

GLOSSARY
VOLTAGE-REGULATOR TERMS AND DEFINITIONS

SHUNT REGULATORS
NOTE: These terms and symbols are based on JEDEC and IEC standards for voltage regulator diodes.
Anode
The electrode to which the regulator current flows within the regulator when it is biased for regulation.
Cathode
The electrode from which the regulator current flows within the regulator when it is biased for regulation .
Dynamic Impedance IZKAI
The quotient of a change in voltage across the regulator and the corresponding change in current through
the regulator when it is biased for regulation.

c

o
ca

-+:;

..
ca..

E

.Ec

Q)

Noise Voltage IVnz )

C

The rms noise voltage with the regulator biased for regulation and with no input ripple.

Q)

e,:,

Reference Input Voltage IVref) lof an adjustable shunt regulator)
The voltage at the reference input terminal with respect to the anode terminal.
Regulator Current (lZ)
The dc current through the regulator when it is biased for regulation.
Regulator Current near Lower Knee of Regulation Range (lZK)
The regulator current near the lower limit of the region within which regulation occurs; this corresponds
to the breakdown knee of a regulator diode.
Regulator Current at Maximum Limit of Regulation Range (lZM)
The regulator current above which the differential resistance of the regulator significantly increases.
Regulator Voltage IVZl
The dc voltage across the regulator.
Shunt Regulator
A device having a voltage-current characteristic similar to that of a voltage-regulator diode. It is normally
biased to operate in a region of low differential resistance (corresponding to the breakdown region of a
regulator diodel and develops across.its terminals an essentially constant voltage throughout a specified
current range.
Temperature Coefficient of Reference Voltage (aVrefl
The ratio of the change in reference voltage to the change in temperature. This is the average value for
the total temperature change.
To obtain a value in ppm/oC:
OIV
ref

=[VrefatT2 - VrefatT1][ 106 ]
Vref at 25°C
T2 - T1

TEXAS •

INSTRUMENTS
POST OFFICE BOX 655012 • DAI.LAS. TEXAS 75265

1-17

C)
CD
:::J
CD

...

!!.

....5'

...o

...o·3

D)

:::J

1-18

~_D_at_a_S_h_e_e_t_s__________________F.~

Contents
Supervisor Functions
Series-Pass Voltage Regulators
Shunt Regulators
Voltage References
DC-to-DC Converters
PWM Controllers

2-2

LM185-2.5, LM285-2.5, LM385-2.5, LM385B·2.5
MICROPOWER VOLTAGE REFERENCES
D3189,JANUARY 1989

• Operating Current Range ..• 20 lolA to
20mA

D8
D PACKAGE
(TOP VIEWI

• 1.5% and 3% Initial Voltage Tolerance

NC
NC

• Reference Impedance ...
LM185 •.. 0.6 !l Max at 25°C
LM385 ... 1 !l Max at 25°C
All Devices ... 1.5 !l Max Over Full
Temperature Range

NC
ANODE

2

7

3
4

6
5

CATHODE
NC
NC
NC

LD PACKAGE

0

(TOP VIEWI

• Very Low Power Consumption
• Applications:
Portable Meter References
Portable Test Instruments
Battery-Operated Systems
Current-Loop Instrumentation
Panel Meters

CA'HOO'

ANOO'

•
...
CI)

Q)
Q)

.c

The anode is in electrical contact with the case.

• Designed to be Interchangeable with
National LM185-2.5, LM285-2.5, and
LM385-2.5

CI)

...
CO
CO

LP PACKAGE
(TOP VIEW)

C

description
These micropower terminal bandgap voltage
references operate over a 20·IJA to 20-mA
current range and feature exceptionally low
dynamic impedance and good temperature
stability. On-chip trimming provides tight voltage
tolerance. The LM185·2.5 series bandgap
reference has low noise and good long-term
stability.
Careful design of the LM185-2.5 series has made
the device exceptionally tolerant of capacitive
loading, making it easy to use in almost any
reference application. The wide dynamic
operating temperature range allows its use with
widely varying supplies with excellent regulation.

ANODE
CATHODE
NC

NC-No internal connection

symbol
ANODE

.-J:

CATHODE

The extremely low-power drain of the LM185-2.5
series makes it useful for micropower circuitry.
These voltage references can be used to make
portable meters, regulators, or general-purpose
analog circuitry with battery life approaching
shelf life. Further, the wide operating current
range allows them to replace older references
with a tighter tolerance part.
The LM185-2.5 is characterized for operation
over the full military temperature range of -55°C
to 125°C. The LM285-2.5 is characterized for
operation from -40°C to 85°C. The LM385-2.5
and LM385B-2.5 are characterized for operation
from O°C to 70°C.
PRODUCTIOI DATA do.um.nts.lntain infarm.llo.
currenl .s of pabli••lian data. Pradum .0010'" 10
speaificatians par the term. If TaxlI Instruments
ol.nd.nI w.,ranty. Praductian ~,.....I.g dOlI nol
.......'ily Incl.d. tasting of III po,.moI8l1.

Copyright © 1989, Texas Instruments Incorporated

TEXAS . "

INSTRUMENTS
POST OFFICE BOX 655012 • DALLAS. TEXAS 75265

2-3

LM185-2.5, LM285-2.5, LM385-2.5, LM385B-2.5
MICROPOWER VOLTAGE REFERENCES
AVAILABLE OPTIONS
PACKAGE
TA

Vz
TOLERANCE

SMALL OUTLINE

METAL CAN

(0)

(LO)

3%

LM385D-2.5

LM385LP-2.5

1.5%

LM385BD-2.5

LM385BLP-2.5

1.5%

LM285D-2.5

O·C
to
70·C

PLASTIC
(LP)

-40·C

to

LM285LD-2.5

LM285LP-2.S

8S·C
-S5·C

to

LM185LD-2.5

1.5%

125·C

The D package
LM385DR-2.5).

C

....
I»
I»

en
:::r

IS

available taped and reeled. Add the suffix R to the device type (I.e.,

schematic
~--------~------~~----~------~~------~~------~--~--CATHOOE

CD
CD

....
en
7;5 kO

50 kO

500 kO

100 kO

5000

60 kO

500 kO

L----4~----------~~----~------~--------~~------~--~---ANOOE

Component values shown are nominal.

2-4

TEXAS ~

INSTRUMENlS
POST OFFICE BOX 666012 • DALLAS, TEXAS 75265

LM185-2.5, LM285-2.5, LM385-2.5, LM385B-2.5
MICROPOWER VOLTAGE REFERENCES
absolute maximum ratings over operating free-air temperature range
Reverse current . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Forward current . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Operating free-air temperature range: LM185-2.5 . . . . . . . . . .
LM285-2.5 . . . . . . . . . .
LM385-2.5, LM385B-2.5
Storage temperature range ................. . . . . . . . .
Lead temperature 1,6 mm (1/16 inch) from case for 10 seconds:
Lead temperature 1,6 mm (1/16 inch) from case for 10 seconds:

. . . . . . . . . . . . . . . . . . . . . . .. 30 mA
. . . . . . . . . . . . . . . . . . . . . . .. 10 mA
. . . . . . . . . . . . . . . .. -55'C to 125'C
. . . . . . . . . . . . . . . . .. -40'C to 85'C
.................... QOC to 70°C
. . . . . . . . . . . . . . . .. -65°C to 150°C
D or LP package ......... "
260'C
LD package .............. 300'C

electrical characteristics at specified free-air temperature
LM185-2.5,
PARAMETER

TEST CONDITIONS

TAt

MIN
Vz

Reference voltage

avz

Average temperature
coefficient of reference Iz = 20
voltage t

!:N z

Change in reference
voltage with current

Iz = 20 I1A to 20 mA

Iz = 20

I1A to 20 mA
I1A to

1 mA

Iz = 1 mA to 20 mA

25'C
25'C

LM385-2.5

LM285-2.5
2.462

TYP

MAX MIN

2.5 2.538 2.425

MAX MIN

2.5 2.575 2.462
±20

±20

25'C

TYP

LM385B-2.5
TYP

UNIT

MAX

2.5 2.538
±20

2

ppml"C

Full range

1
1.5

2.5

2
2.5

25'C

10

20

20

Full range

20

25

V

mV

Iz(min)

Minimum reference
current

Full range

8

20

8

20

8

20

I1A

Zz

Reference impedance

Iz=10011A

25'C
Full range

0.2

0.6

0.4

1

0.4

1
1.5

n

Vn

Broadband noise
voltage

Iz = 100 11A,
f= 10Hzto10kHz

25'C

120

25'C

±20

±20

1.5

±20

1.5
120

CI)
CI)

.s:

f/)

...
C

25

Long·term change in
reference voltage

I1A

tI)

CO
CO

!:Nz/!lt

Iz = 100

II
...

120

ppm/khr

I1V

t Full range IS -55'C to 125'C for the LM185M·2.5, -40'C to 85'C for the LM285·2.5, and O'C to 70'C for the LM385-2.5 and LM385B-2.5.
t The average temperature coefficient of reference voltage is defined as the total change in reference voltage divided by the specified
temperature range.

TEXAS ~

INSTRUMENTS
POST OFFICE BOX 655012 • DALLAS, TeXAS 76265

2-5

LM185-2.5, LM285-2.5, LM385-2.5, LM385B-2.5

MICROPOWER VOLTAGE REFERENCES
TYPICAL CHARACTERISTICSt
REFERENCE VOLTAGE CHANGE
WITH
REVERSE CURRENT

REVERSE CHARACTERISTICS

100

16

TA - -55°C to 125°C

TA - -55°C to 125°C

>

E

'1
I

10

C
~

c
0).

r+
0)

en
-:r

V

8

1/

j
I

!f.

CD
CD

r+
II)

0.1

12

'"
.c
C
III

(J

I---

I

8

II

'"

V

~
0

>

II

4

u

c

!

7

o

--

I

II

V~

~
II:

0

I

N

>


&

& 2.510

~

~ 2.505

1./

E

:'l
Iii

J......--

.f

~0.4

2.515

I

"E 0.8
I

I-

i&!

~

2.500

I
-:: 2,490

o
0.1

10

100

V

2.495

2.485
0.01

100

10

0.1

VR-Ravarsa Voltaga-V

.........

I--"

~

"" "

/V

V

2.480
-55-35-15

5

25

45

65

85 105125

TA-Fraa-Air Tamparatura- °C

'F-Forward Currant-mA

FIGURE 4

FIGURE 3

toata at high and low temperatures are applicable only within the rated operating free-air temperature ranges of the various devices.

2-6

TEXAS •

INSTRUMENTS
POST OFFICE BOX 655012 • DALLAS, TeXAS 75265

LM185-2.5, LM285-2.5, LM385-2.5, LM385B-2.5

MICROPOWER VOLTAGE REFERENCE
TYPICAL CHARACTERISTICS
REFERENCE IMPEDANCE
vs
FREQUENCY

REFERENCE IMPEDANCE
vs
REFERENCE CURRENT

1000

TA - MIN to MAX

c::
I

II
U
C

c::

.,uI

100

co

...

II

Iz - 100 p.A
TA - 25°C

1 k

c

co

1\

'tI

.5

10 k

IIIII

fl_I~~I~z

'tI

...

II

100

V
/

.5.,

10

II
U

u

c
!

c

!

"-

-!

II:

I

N

N

0.1
0.01

10

.!II
II:

-.

I

OJ

0.1

:
'0

~

FILTERED RMS OUTPUT NOISE VOLTAGE
vs
FREQUENCY
120
R

C

~
0

>

.....

.~

80

/

z

...

S
600

'$
0

!\

400

II)

1 k

10 k

40

V

II:
'tI

!
~

iI:

100

60

:E

1\

200

10

RC LOW PASS

...

800

o

fi'" '"

>:l.
~ 100

c

>

1000

FIGURE 6

Iz - 100 p.A
1200 TA - 25°C

f

100

10
f - Frequency- kHz

1400

>

..c
UJ

o

0.1
0.01

100

NOISE VOLTAGE
vs
FREQUENCY

I

en

Q)
Q)

ca

FIGURES

II

&I
...

/

/

Iz-Reference Current-rnA

~c 1000

V

10

10

0.1

,/

N

I--

V

100 k

20

/

--...-

o
0.1

10

100

f-Frequency-kHz

f-Frequency-Hz

FIGURE 8

FIGURE 7

TEXAS ",
INSTRUMENTS
POST OFFICE BOX 655012 • DALLAS. TEXAS 75265

2-7

LM185-2.5, LM285-2.5, LM385-2.5, LM385B-2.5

MICROPOWER VOLTAGE REFERENCE

TYPICAL CHARACTERISTICS
TRANSIENT RESPONSE
A
-V-

~ 4

I

3

/'

>

... 2
0 1
...
5... 0
..5
5
5

,

OUTPUT A
24 kll

VI'VO

C

C

...

IV

Q)
Q)

t/)

5

::T
CD
CD

0

...en

{

A

1NiUT -AV

o

100
t-Time-,.s

-\J

500

FIGURE 9

TYPICAL APPLICATION DATA

2 MERCURY +
CELLS
-

2.6 V

10 kll
ADJUST
FOR

12.17 mV
AT 25°C
ACROSS

METER

450 II

FIGURE 10. THERMOCOUPLE COLD-JUNCTION COMPENSATOR
V+

f,

3.7VsV+s30V
R

9:

2.7 kll

......------'~2.5 V

20kll

2.5 V

LM385-2.5
-::'

FIGURE 11. OPERATION OVER
A WIDE SUPPLY RANGE

2-8

FIGURE 12_ REFERENCE FROM A g-V BATTERY

TEXAS .."

INSIRUMENTS
POST OFFICE BOX 665012 • DALLAS, TeXAS 76265

LM217. LM317
3·TERMINAL ADJUSTABLE REGULATORS
02212. SEPTEMBER. 1977-REVISEO FEBRUARY 1988

•

Output Voltage Range Adjustable from
1.2 V to 37 V

•

Peak Output Current Constant Over
Temperature Range of Regulator

•

Output Current Capability
of 1.5 A Max

•

Popular 3·Lead TO·220AB Package·

•

Ripple Rejection Typically BO dB

•

Direct Replacement for National LM217
and LM317

•

Input Regulation Typically 0.01% Per
Input·Volt Change

•

Output Regulation Typically 0.1 %

terminal assignments
KC PACKAGE

(TOP VIEW)

Ir I

....enCD

e::-INPUT

J__JF===:,:==~~j0~iMENT

CD

[e;::=

.r:.
(J)

THE OUTPUT TERMINAL IS IN
ELECTRICAL CONTACT WITH
THE MOUNTING BASE

....asas

C

TO·22AB

description
The LM217 and LM317 are adjustable 3·terminal positive·voltage regulators capable of supplying 1.5 A
over a differential voltage range of 3 V to 40 V. They are exceptionally easy to use and require only two
external resistors to set the output voltage. Both input and output regulation are better than standard fixed
regulators. The devices are packaged in a standard transistor package that is easily mounted and handled.
In addition to higher performance than fixed regulators. these regulators offer full overload protection
available only in integrated circuits. Included on the chip are current limit. thermal overload protection.
and safe·area protection. All overload protection circuitry remains fully functional even if the adjustment
terminal is disconnected. Normally. no capacitors are needed unless the device is situated far from the
input filter capacitors in which case an input bypass is needed. An optional output capacitor can be added
to improve transient response. The adjustment terminal can be bypassed to achieve very high ripple rejection.
which is difficult to achieve with standard 3-terminal regulators.
Besides replacing fixed regulators. these regulators are useful in a wide variety of other applications. The
primary applications of each of these regulators is that of a programmable output regulator. but by
connecting a fixed resistor between the adjustment terminal and the output terminal. each device can be
used as a precision current regulator. Even though the regulator is floating and sees only the input·to-output
differential voltage. use of these devices to regulate output voltages that would cause the maximum-rated
differential voltage to be exceeded if the output became shorted to ground is not recommended. The TL783
is recommended for output voltages exceeding 37 V. Supplies with electronic shutdown can be achieved
by clamping the adjustment terminal to ground. which programs the output to 1.2 V where most loads
draw little current.

PRDDUCTIDI DATA d.cumlnll contain infarmation
eumnt I I of publication data. Praducts co.form to
.paclflcllio.s por thl t ..... of TI... Instrumlnts

=~~i;·i~r:1~7i =:~:r :.~u::;::£::~ not

Copyright © 1982, Texas Instruments Incorporated

TEXAS . "

INSTRUMENTS
POST OFFICE BOX 655012 • DALLAS, TEXAS 75265

2-9

LM217. LM317
3·TERMINAL ADJUSTABLE REGULATORS
The LM217 and LM317 are characterized for operation from - 25°C to 150°C and from O°C to 125°C,
respectively.

schematic
r---.---~----.---~----~~--------------------~~------.-~INPUT

c

...
OJ
OJ

en

::r
(1)

...
(1)

(I)

~~--~----~~~~~~~~~~-4----~--~~~~------------~~~OUTPUT

~----------------------------ADJUSTMENT

absolute maximum ratings over operating temperature range (unless otherwise noted)
LM217
40

LM317
40

UNIT
V

2000

2000

mW

15

Operating free-air, case, or virtual junction temperature range

20
-25 to 150

W
·C

Storage temperature range

-65 to 150

-65 to 150

·C

260

260

·C

Input-to-output differential voltage, VI - Vo
Continuous total dissipation at 25°C free-air temperature (see Note 1)

Continuous total dissipation at (or below) 25·C case temperature (see Note 1)

Lead temperature 1,6 mm (1/16 inch) from case for 10 seconds

o to

125

NOTE 1: For operation above 25°C free-air or case temperature, refer to Figures 15 and 16. To avoid exceeding the design maximum
virtual junction temperature, these ratings should not be exceeded. Due to variations in individual device electrical characteristics
and thermal resistance, the built-in thermal overload protection may be activated at power levels slightly above or below the
rated dissipation.

recommended operating conditions
LM217
Output current, 10
Operating virtual junction temperature, T J

2-10

TEXAS . "

INSTRUMENlS
POST OFFICE BOX 655012 • DALLAS, TeXAS 75265

LM317

MIN

MAX

MIN

MAX

5

1500

10

1500

-25

150

0

125

UNIT
mA
·C

LM217, LM317
3·TERMINAL ADJUSTABLE REGULATORS
electrical characteristics over recommended ranges of operating virtual junction temperature (unless
otherwise noted) (see Note 2)
TEST CONDITIONSt

PARAMETER

LM317

LM217
MIN

TYP

MAX

MIN

TYP

MAX

Input regulation

VI- Va

~

3Vt040V, TJ

~

MIN to MAX

0.01

0.02

0.01

0.04

(See Note 3)

See Note 4

10

~

10mAto 1.5A

0.02

0.05

0.02

0.07

Ripple rejection

Va

~

10V,

f~120Hz

Va

~

10 V,

f

~

120 Hz,

10-pF capacitor between ADJ and ground
10
Output regulation

~

Output voltage
long-term drift
(see Note 51

Output noise voltage
Minimum output current

to maintain regulation
Peak output current

80

66

dB

80

mV

Vo:s 5 V

5

15

5

25

Va> 5 V

0.1

0.3

0.1

0.5

%

)0

Vo:s 5V

20

50

20

70

mV

Va> 5 V

0.3

1

0.3

1.5

%

10mAto 1.5 A,

See Note 4

Output voltage change
with temperature

66

%/V

65

TJ ~ 25°C, See Note 4
~

10 mAto 1.5 A,

65

UNIT

...
CI)

TJ ~ MIN to MAX
After 1000 h at TJ

1
~

MAX

0.3

and VI - Va ~ 40 V
f

~

10 Hz to 10 kHz, TJ

~

25°C

3.5
1.5

VI - Va :s 15 V
~

25°C

Adjustment-terminal
current
Change in adjustment-

VI - Va

terminal current

10

Reference voltage
(output to ADJ)

VI - Va
10

~

~

~

2.5 V to 40 V,

10 mA to 1.5 A
~

3 V to 40 V,

10mAto 1.5A,

P :s 15W

1

0.3

1.2

%

1

0.003

0.003

VI - Va ~ 40 V

VI - Va :s 40 V, TJ

1

5

3.5

2.2

1.5

2.2

0.4

0.15

0.4

10

%
%

...

rnA

C

CO
CO

A

50

100

50

100

pA

0.2

5

0.2

5

pA

1.25

1.3

1.25

1.3

1.2

Q)
Q)

.c
en

V

tUnless otherwise noted, these specifications apply for the following test conditions; VI - Va ~ 5 V and 10 ~ 0.5 A. For conditions
shown as MIN or MAX. use the appropriate value specified under recommended operating conditions.

NOTES: 2. All characteristics are measured with a O.1-I'F capacitor across the input and a l-I'F capacitor across the output.
3. Input regulation is expressed here as the percentage change in output voltage per 1-V change at the input.
4. Pulse testing techniques are used to maintain the junction temperature as close to the ambient temperature as possible. Thermal
effects must be taken into account separately.
5. Since long-term drift cannot be measured on the individual devices prior to shipment, this specification is not intended to be
a guarantee or warranty. It is an engineering estimate of the average drift to be expected from lot to lot.

TEXAS •

INSTRUMENTS
POST OFFICE BOX 655012 • DALLAS, TEXAS 75265

2-11

LM217, LM317
3·TERMINAL ADJUSTABLE REGULATORS
TYPICAL APPLICATION DATA

VI

va
Isee Note CI

+35 V

Cl
O.lI'F

C2 - 11'F
(see Note

Va
Rl
12011

BI

R2
3 kll

C

I»
r+
I»

FIGURE 1. ADJUSTABLE
VOLTAGE REGULATOR

en

FIGURE 2. O-V to 30-V
REGULATOR CIRCUIT

::r
CD
CD

r+

en

V+

V+

~-'~-'~--~~VO

...........J\JV\r-e>-llimit -

01 t
lN4002
Cl
O.lI'F

C3

+

11'F

t01 discharges C2
if output is shorted to ground.

FIGURE 3. ADJUSTABLE
REGULATOR CIRCUIT WITH
IMPROVED RIPPLE REJECTION

FIGURE 4. PRECISION CURRENT
LIMITER CIRCUIT

NOTES: A. Use of an input bypass capacitor is recommended if regulator is far from filter capacitors.
B. Use of an output capacitor improves transient response but is optional.

C. Output voltage is calculated from the equation:

Va = Vref

~

+

~)

Vref equals the difference between the output and adjustment terminal voltages.

2-12

TEXAS . "

INSTRUMENTS
POST OFFICE BOX 655012 • DALLAS. TEXAS 75265

1.2

R1

LM217. LM317
3-TERMINAL ADJUSTABLE REGULATORS
TYPICAL APPLICATIONS
Rl
240 !l

R2

V+

720 !l

V+

Vo
R3

Ell

R4

~----~------------------~

1 k!l

....
U)

FIGURE 6. 1.2 to 20-V
REGULATOR CIRCUIT WITH
MINIMUM PROGRAM CURRENT

FIGURE 5. TRACKING
PREREGULATOR CIRCUIT

Q)
Q)

.c

en

....CtICtI

V+

Vo

C

Vo

Minimum load current from each output is 10 rnA.
All output voltage will be within 200 mV of each other.

FIGURE 7. ADJUSTING MULTIPLE ON-CARD REGULATORS WITH A SINGLE CONTROL

V+

V+

I
tRs controls output impedance of charger
ZOUT

=

RS I'

+

R2

Ai" )

The use of RS allows low charging rates
with a fully-charged battery.

FIGURE 9. 50-rnA CONSTANTCURRENT BATTERY CHARGER
CIRCUIT

FIGURE 8. BATTERY CHARGER
CIRCUIT

TEXAS

~

INSTRUMENTS
POST OFFICE BOX 655012 • DALLAS. TeXAS 75265

2-13

LM217, LM317
3-TERMINAL ADJUSTABLE REGULATORS
TYPICAL APPLICATIONS

V+
120 !l
6-V POp

12 V pop

c.o

'--__+_.. 2 W Average
~
480 !l

c
....

C»
C»

en

FIGURE 10_ SLOW-TURN-ON 15-V
REGULATOR CIRCUIT

FIGURE 11. A-C VOLTAGE
REGULATOR CIRCUIT

::r
CD

....CD
(II

0.2 !l

V+

V+
0.2 !l

4.5 V to 25 V

0.2 !l

1000

V-----e~--~

5 k!l

*This resistor sets peak current (0.6 A for 1 0)

1.5 kO

FIGURE 12_ CURRENT-LIMITED
6-V CHARGER

2-14

FIGURE 13. ADJUSTABLE 4-A
REGULATOR

TEXAS . "

INSTRUMENTS
POST OFFICE BOX 665012 • DALLAS, TEXAS 75265

LM217. LM317
3-TERMINAL ADJUSTABLE REGULATORS
TYPICAL APPLICATIONS
TIP73

500 II

v+

5 kll
2211

II
...
II)

CD
CD

..c:

til

...asas

, Minimum load current is 30 rnA.
§Optional capacitor improves ripple rejection

C

FIGURE 14. HIGH-CURRENT
ADJUSTABLE REGULATOR

THERMAL INFORMATION
FREE-AIR TEMPERATURE
DISSIPATION DERATING CURVE
2000

;:

1800

I
c

1600

.

1200

E

.....
••is...

"'-

0

1400

"c
"
~

1000

u
E

600

.~"

..

400

::E

200

0

800

0

o

25

'""'-

CASE TEMPERATURE
DISSIPATION DERATING CURVE

I
.1
T
Derating factor - 16 mW/oC_
RUA ~ 62.5°C/W

16

;:
I

\.

14

'\

c

'"'"
'"

12

.

10

..•

•

is

"c
"
0

.~

~

'"

0

u
E
E
.j(

"

.

~

100
75
50
125
TA -Free-Air Temperature- °c

FIGURE 15

~...

'"

::E

150

TEXAS

[\

\

8

6

'\

1\

4
Derating Factor - 0.25 W/oc
2 above 900C
RUC ~ 4°CIW

o

25

75
100
50
125
Tc-Case Temperature- °c

\

\
150

FIGURE 16

+

INSTRUMENTS

POST OFFICE BOX 855012 • DALLAS, TEXAS 75285

2-15

c
Q)

r+
Q)

en
::::r
CD
CD

r+
C/)

2-16

LM237, LM337
3·TERMINAL ADJUSTABLE REGULATORS
02640. NOVEMBER 1981-REVISED FEBRUARY 1988

•

Output Voltage Range Adjustable from
- 1.2 V to - 37 V

•

10 Capability of 1.5 A Max

•

Input Regulation Typically 0.01 % per InputVolt Change

•

Output Regulation Typically 0.3%

•

Peak Output Current Constant Over
Temperature Range of Regulator

•

Ripple Rejection Typically 77 dB

•

Direct Replacement for National
Semiconductor LM237, LM337

LM237, LM337 ... KC PACKAGE
ITOPVIEW}

THE INPUT TERMINAL IS IN
ELECTRICAL CONTACT WITH
THE MOUNTING BASE
TO·220AB

•
....en

Q)
Q)

description

.s::.
en

The LM237 and LM337 are adjustable 3-terminal negative-voltage regulators capable of supplying in excess
of -1.5 A over an output voltage range of -1.2 V to - 37 V. They are exceptionally easy to use, requiring
only two external resistors to set the output voltage and one output capacitor for frequency compensation.
The current design has been optimized for excellent regulation and low thermal transients. In addition,
the LM237 and LM337 feature internal current limiting, thermal shutdown, and safe-area compensation,
making them virtually immune to blowout by overloads.

....COCO

C

The LM237 and LM337 serve a wide variety of applications including local on-card regulation, programmable
output voltage regulation, or precision current regulation. They are ideal complements to the LM217 and
LM317 adjustable positive-voltage regulators.

schematic diagram
r-~--------~------~----~---¥~------A~USTMENT

r------.------~----~--1_~==~~==~--_4_F~~~._1_----~~-OUTPUT

~--~~~--~~~-+------~~------~--

PRODUCTION DATA documl.l••ontli. i.lorm.tion
cur...... of .....Ii...io. d.... ProduOll co.form to
spacifications per the tertii of T8.1. Illtlll.ants

===i~·i:I'::li

=::i:r ~=::.:~~

not

__--------_+----------+_

INPUT

Copyright @ 1983. Texas Instruments Incorporated

TEXAS ."

INSTRUMENTS
POST OFFICE BOX 655012 • DALLAS, TEXAS 75265

2-17

LM237, LM337
3-TERMINAL ADJUSTABLE REGULATORS
absolute maximum ratings over operating temperature range (unless otherwise noted)
Input-to-output differential voltage, VI - Vo .................................... -40 V
Continuous total dissipation at 25°C free-air temperature (see Note 1) .. . . . . . . . . . . . . . . . .. 2 W
Continuous total dissipation at (or below) 25°C case temperature (see Note 1) . . . . . . . . . . .. 15 W
Operating free-air, case, or virtual junction temperature range: LM237 ......... -25°C to 150°C
LM337 ........... OOC to 125°C
Storage temperature range ........................ ; ................ -65°C to 150°C
Lead temperature 1,6 mm (1/16 inch) from case for 10 seconds. . . . . . . . . . . . . . . . . . . . .. 260°C
NOTE 1: For operation above 25°C free-air or case temperature, refer to Figures 1 and 2. To avoid exceeding the design maximum virtual
junction temperature. these ratings should not be exceeded. Due to variations in individual devic~ electrical characteristics and
thermal resistance, the built-in thermal overload protection may be activated at power levels slightly above or below the rated
dissipation.

C

FREE-AIR TEMPERATURE
DISSIPATION DERATING CURVE

...mm
en

::r
(1)

...
en
(1)

2000

~ 1800
I
g 1600

I"

..

11400
·iii

.B

is 1200
1000

c

~ 800

c3

"-

:=I

""

"

.

::E 200
25

~

·i

is..
"

~

600

E
E
.j( 400

o

16

'""-"-

KC (T0220AB) package
Derating factor - 16 mW/oC
RUA '" 62.5 OC/W

I

I

\

12

\

10
8

i

6

0

\

14

0

"

CASE TEMPERATURE
DISSIPATION DERATING CURVE

E

I

4

::E

2

.

~

100
125
75
50
TA -Free-Air Temperature- °C

"E

.j(

"-

150

o

\

1\

CJ

Derating factor - 0.25 W/oC
above 90°C
ROJC '" 4°C/W

25

50
75
125
100
Tc-Case Temperature- °C

FIGURE 2

FIGURE 1

2-18

\

TEXAS . "

INSTRUMENTS
POST OFFICE BOX 656012 • DALLAS. TEXAS 75265

~

\
150

LM237. LM337
3·TERMINAL ADJUSTABLE REGULATORS
recommended operating conditions
LM237

Output current, 10

LM337

MIN

MAX

MIN

MAX

IVI - Vol ,;40 V,
P,; 15 W

10

1500

10

1500

IVI - Vol ,; 10 V,
P,;15W

6

1500

6

1500

-25

150

0

125

Operating virtual junction temperature, T J

UNIT

rnA

°C

electrical characteristics over recommended ranges of operating virtual junction temperature (unless
otherwise noted)
PARAMETER
Input regulation:!:

Ripple rejection

VI - Vo

~

-3Vto -40V

0.04

TJ

~

MIN to MAX

0.02

0.05

0.02

0.07

f

-10 V,

f

change with temperature

Output voltage
long-term drift
(see Note 21

TJ

~

~

120 Hz

~

120 Hz

60

~

~

66

50
1

50

70

rnV

1.5

%

0.3

1

0.3

0.003

1

5

2.5

10

0.003

lVI-Vol ,;10 V

1.2

3

1.5

6

current to maintain
lVI-Vol ,;15 V
IVI -Vol ,;40 V,

TJ

~

25°C

1.5

2.2

1.5

2.2

0.24

0.4

0.15

0.4

terminal current

Reference voltage

(output to ADJI
Thermal regulation

%

rnA

Adjustment-

terminal current

CO
CO

%

2.5

~

CI)

%

lVI-Vol ,;40 V

TJ

25°C

0.6

f

Change in adjustment

C

0.5

Minimum output

Peak output current

%

IVol;,,5 V

Output noise voltage

regulation

..

IVol,;5 V

MAX and

10Hz to 10kHz,

rnV

dB

25

-40 V

Q)
Q)

J:

77

1

III
..
(fj

%IV

IVol,;5 V

0.6
~

After 1000 h at T J

UNIT

60

77

66

MIN to MAX

VI - Va

MAX

0.01

IVol;,,5 V

Output voltage

TYP

0.02

-10 V,

25°C

MIN

0.01

~

~

MAX

25°C

~

10 10 rnA to 1 .5 A

LM337

TYP

~

Va

TJ

MIN

TJ

Va

CADJ ~ 10 ~F
10 ~ 10 rnA to 1 .5 A,
Output regulation

LM237

TEST CONDITIONSt

VI - Va
10

~

~

- 2.5 V to -40 V,

10 rnA to MAX,

VI-Va
10

~

~

TJ

-3 to -40 V,

TJ

~

25°C

~

25°C

~

MIN to MAX

A

65

100

65

100

~A

2

5

2

5

~A

-1.225 -, .250 -, .275 -1.213

-, .25 -1.287
V

10 rnA to 1.5 A,

P :5 rated dissipation

Initial T J

~

25°C,

TJ

-1.2 -1.25

-1.3

-1.2 -1.25

-1.3

0.002

0.02

0.003

0.04

10-ms pulse

%/W

tUnless otherwise noted, these specifications apply for the following test conditions IVI~Vol = 5 V and 10 = 0.5 A. For conditions
shown as MIN or MAX, use the appropriate value specified under recommended operating conditions. All characteristics are measured
with a o. l-,aF capacitor across the input and a 1-,aF capacitor across the output. Pulse testing techniques are used to maintain the junction
temperature as close to the ambient temperature as possible. Thermal effects must be taken into account separately.
:l:lnput regulation is expressed here as the percentage change in output voltage per 1-volt change at the input.
NOTE 2: Since long-term drift cannot be measured on the individual devices prior to shipment, this specification is not intended to be
a guarantee or warranty. It is an engineering estimate of the average drift to be expected from lot to lot.

TEXAS •

INSTRUMENTS
POST OFFICE BOX 655012 • DALLAS, TEXAS 75265

2-19

LM237, LM337
3·TERMINAL ADJUSTABLE REGULATORS

TYPICAL APPLICATION DATA
LM237
OR
LM337

OUT~~---e-----va

VI - - - " - - l I N

C2

I

c

Q)

r+
Q)

en
:::r

R1 is typically 120 O.

r+

-Va
)
R2 = R1 ( - - - 1
-1.25

CD
CD

tn

where

Vo

is the output in volts.

C1 is a 1-I'F solid tantalum required only if the regulator is more than 10 em (4 in. I from the
power supply filter capacitor.
C2 is a 1-I'F solid tantalum or 10-I'F aluminum electrolytic required for stability.

FIGURE 3. ADJUSTABLE NEGATIVE·VOLTAGE REGULATOR
LM237
OR
LM337

VI

I"

ADJ

o+-~

Va

J
1.25V
RS - 'LIMIT

FIGURE 4. CURRENT·LIMITING CIRCUIT

2-20

TEXAS . "

INSTRUMENTS
POST OFFICE BOX 655012 • DALLAS, TEXAS 75265

LM330
3-TERMINAL POSITIVE REGULATOR
APRIL 1983-REVISED APRIL 1988

•

Input-Output Differential Less than 0.6 V

•

Output Current of 150 mA

KCPACKAGE
(TOPVIEWI

•

Reverse Polarity Protection

•

Line Transient Protection

•

Internal Short-Circuit Current Limiting

•

Internal Thermal Overload Protection

•

Mirror-Image Insertion Protection

•

Direct Replacement for National LM330T-5.0

THE COMMON TERMINAL IS IN
ELECTRICAL CONTACT WITH
THE MOUNTING BASE
TO-220AB

•

~'

...
II)

Q)
Q)

description

.c

The LM330 3-terminal positive regulator features an ability to source 150 mA of output current with an
input-output differential of 0.6 volt or less. Familar regulator features such as current limit and thermal
overload protection are also provided.

CJ)

The LM330 has low dropout voltage making it useful for certain battery applications. For example. since
the low dropout voltage allows a longer battery discharge before the output falls out of regulation. a battery
supplying the regulator input voltage may discharge to 5.6 V and still properly regulate the system and
load voltage. The LM330 protects both itself and the regulated system from reverse installation of batteries.

C

...caca

Other protection features include line transient protection above 40 V. where the output actually shuts
down to avoid damaging internal and external circuits. The LM330 regulator cannot be harmed by temporary
mirror-image insertion.

schematic diagram

-....--"fl-.....---1r----,

I N P U T - - - t - - - t - - - t - - . . - -........ . - - - - - t - -.....

,.n

soon

OUTPUT

3kn

lolkn
4.4kn

1.SkO

COMMON-+-~~-+_--~_-~-_~

620n
Ion

10n

1kQ

_ _ _ _ _ _~-+_ _4_~~---4_ _ _~

Resistor values shown are nominal.

PRODUCTION DATA documants contain information
currant .s of publicatioo dlta. Praducts conform to
specificatiDnl par the terms of raxi. Instruments

::::~~i~t::I':.1~ ~::i~~i:; :1~D=::~~~s

not

Copyright © 1983 Texas Instruments Incorporated

TEXAS . "

INSTRUMENTS
POST OFFICE BOX 655012 • DALLAS, TEXAS 75265

2-21

LM330
3-TERMINAL POSITIVE REGULATOR
absolute maximum ratings over operating free-air temperature range (unless otherwise noted)
Continuous input voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 V
Transient input voltage t = 1 s . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 40 V
Continuous total dissipation at 25 DC free-air temperature (see Note 1) .................. 2 W
Continuous total dissipation at (or below) case temperature (see Note 1) ............... 15 W
Operating free-air, case, or virtual junction temperature . . . . . . . . . . . . . . . . . . . - 55 DC to 150 DC
Storage temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . - 65 DC to 150 DC
Lead temperature 1,6 mm (1/16 inch) from case for 10 seconds . . . . . . . . . . . . . . . . . . . . 260 DC

•

NOTE 1: For operation above 25°C free-air or case temperature, refer to Figures 1 and 2. To avoid exceeding the design maximum virtual
junction temperature, these ratings should not be exceeded. Due to variations in individual device electrical characteristics and
thermal resistance, the built-in thermal overload protection may be activated at power levels slightly above or below the rated
dissipation.

FREE-AIR TEMPERATURE
DISSIPATION DERATING CURVE

2000

==E
I

c

1600

...

1400

.5!

1;;

':

..

[\.

1800

:>

0

:>

1000

c

.~

<3

800

E
E

600

·x

400

::iE

200

:>

..

o

25

16

Derating factor = 16 mWfC
ROJA"" 62.5°CIW

'"I"
'"

0 1200

CASE TEMPERATURE
DISSIPATION DERATING CURVE

==cI
0

.~

...

\

14

\

12

1\

':

~

.

i5 10

'"I"

:>
0
:>

c
0

""
'"

50
75
100
125
TA-Free-Air Temperature-oC

FIGURE 1

\

8

.~

150

u
E
:>
E

.

·x
::iE

6

\

\

4
Derating factor - 250 mW/oC
2
above 90°C
ROJC,,=4°C/W

o

25

100
125
75
50
Tc-Case Temperature-OC

FIGURE 2

recommended operating conditions
MIN
5

Output current

o

Operating virtual junction temperature

2-22

TEXAS .."

INSTRUMENTS
POST OFFICE BOX 666012 • DALLAS. TEXAS 75265

MAX
150
100

\

\

150

LM330
3·TERMINAL POSITIVE REGULATOR
electrical characteristics at 25°C virtual junction temperature. VI
otherwise noted)
PARAMETERS
Output voltage

14 V. 10

TEST CONDITIONSt
VI - 6 V to 26 V.
TJ = ODC to 100 DC

MIN

TYP

MAX

4.8

5

5.2

=9Vto16V

7

25

= 6 V to 26 V

30

60

10 = 5 mA to 150 mAo

I VI
I VI

Input regulation

150 rnA. (unless

Ripple rejection

I-120Hz

56

Output regulation

10 = 5 mA to 150 mA

14

Output voltage longterm driftt

After 1000 h at TJ = 150 DC

Dropout voltage

10 - 150 mA

Output noise voltage
Output voltage with

I - 10 Hz to 100 kHz

input polarity reversed
Output voltage with

VI = 60 V.

input transient

VI - 50 V.

Bias current with input

transient

VI = -30 V. t = 100 ms

I VI

<5.5

t - 1s

<5.5

I VI
I VI

RL = 1000

26

voltage
Output impedance

10 - 100 mAo 10 - 10 mA (rms). I - 100 Hz to 10 kHz
10 = 10 mA

Bias current

10 = 50 mA
10 = 150 mA
VI - 6 V to 26 V

Bias current change

V

150

...
G)
G)

.c
(1J

...

45

V

C

200

mO

3.5

7

5

11

18

40

10

Peak output current

•

mA

-80

= -6 V. t = 1 s

Overvoltage shutdown

V

14

= 40 V. t = 1 s

V

!II

>-0.3

t = 100 ms

mV

/LV

>-0.3

= -12 V. DC

mV

mV
0.6

50

I

RL = 1000

V

dB

50

20
0.32

UNIT

420

a:I
a:I

mA

%
700

mA

t Pulse testing techniques are used to maintain the junction temperature as close to the ambient temperature as possible. Thermal effects
must be taken into account separately. All characteristics are measured with a O. 1-JtF capacitor across the input and a 10-"F capacitor
across the output.

+Since long-term drift cannot be measured on the individual devices prior to shipment, this specification is not intended to be a guarantee
or warranty. It is an engineering estimate of the average drift to be expected from lot to lot.

TEXAS •

INSTRUMENTS
POST OFFICE BOX 655012 • DALLAS. TEXAS 75265

2-23

LM330
3·TERMINAL POSITIVE REGULATOR
TYPICAL CHARACTERISTICS
OUTPUT VOLTAGE

OUTPUT VOLTAGE

vs

vs

VIRTUAL JUNCTION TEMPERATURE

INPUT VOLTAGE

8

5.025

R~ = 10~ n

7

S

5.000

..........

/'

]>
.. I

",

E.U4.975
., ...

~l(l

"~

c ;::
'0

I»

;'"

... »

5:::I

o

:5

~

~

=
a. 4

1\

o= 3 r---- f--.
I

o
> 2

4.925

CD
CD

...en

6

~

-E 4.950

I»

en
::r

>

VI = 14 V

I I

4.900

o

-60 -40 -20 0

20 40 60 80 100 120 140
TJ-Virtual Junction Temperature-·C

o

FIGURE 4

OUTPUT VOLTAGE

vs

INPUT VOLTAGE

INPUT VOLTAGE

600

-IJ= 1~OJA
V

4

/

>
...
:::I

5:::I

0
I
0

I •

TJ=25 C

500

>I
'0

PEAK OUTPUT CURRENT

vs

5

.,
J!'"

«
E
.!.I:

/

.,

3

~ 300

~:::I

9 200

/

.><

~

,IV
2

I

I
/

I

I
3
4
5
VI-Input Voltage-V

6

o
o

a40.C

~

5

10
15
20
VI-Input Voltage-V

FIGURE 6

FIGURE 5

2-24

/ ' ---- ~

--1- .

TJ= 125 C

100

V
2

~

400

~

/

>

60

45

VI-Input Voltage-V

FIGURE 3

6

30

15

TEXAS ..,
INSTRUMENTS
POST OFFICE BOX 655012 • DALLAS, TEXAS 75265

25

30

LM330
3·TERMINAL POSITIVE REGULATOR
TYPICAL CHARACTERISTICS
RIPPLE REJECTION

RIPPLE REJECTION

vs

vs

FREQUENCY

OUTPUT CURRENT

80

80

IJ=50~A
70 .....-1\ VI = 14V
60

"'"

1 1

_ VI-V O=9V
fO= 120 Hz

..,

60

-

III

~

"

I
c

/

II
...

.2
U
';' 40

,-'

II)

..

Il:

CI)
CI)

Q.

.eIl:

20

.c
tJ)

20

...
CO
CO

10

o

1

10

100
1k
10 k
f-Frequency-Hz

100 k

o

1M

C
o

50
100
IO-Output Current-rnA

150

FIGURE 8

FIGURE 7

DROPOUT VOLTAGE

DROPOUT VOLTAGE

vs

vs

VIRTUAL JUNCTION TEMPERATURE

OUTPUT CURRENT

0.6

0.6

I

1

TJ=25 C
0.5

..

0.4

~

0.3

~
~

:;

8.

~

0.2

0.1

o

,--

----

----

,-o

-

0.5

..

~

10= 150 rnA

0.4

~

o

./

> 0.3
~a.
~

10-50mA

I

0.1

lo-10mA

I

o

50
25
75
100
125
TJ-Virtual Junction Temperature-OC

150

/"

0.2

/

Y

o

/'"

/

50

100
150
IO-Output Current-rnA

200

FIGURE 10

FIGURE 9

TEXAS ."

INSTRUMENTS
POST OFFICE BOX 655012 • DALLAS, TEXAS 75265

2·25

LM330
3·TERMINAL POSITIVE REGULATOR
TYPICAL CHARACTERISTICS
OUTPUT IMPEDANCE
vs
FREQUENCY

INPUT CURRENT
vs
INPUT VOLTAGE

10
10-50 mA
TJ - 25°C

•

7

~

I

..

30

,

«

T 20

8c

~

Q.

.."

....

8 15

I

'"
.§

C»
C»

V

f!

"D

C

RL = 100 n
TJ = 15°C

25

S- 0.1

V

<;;

r:7

Q.

./

c

1 10

tn 0"
::T
CD
CD

5

....
en

0.01

1

10

100
1k
10 k
f-Frequency-Hz

100 k

o

1M

45

40

35

FIGURE 12

FIGURE 11

INPUT CURRENT
vs
REVERSE INPUT VOLTAGE

LINE TRANSIENT RESPONSE

~

~>

~

T

.. c

a.S!

cIL=~oJ7 "\

TJ=25°C
10 = 150 mA

20
0

'-

"'"

o~ .i>

f\

J

b~-20

\11

>

50

I °
TJ=25C

o
«

E

1\ -)
\1/

1\ 7

55

50

VI-Input Voltage-V

I
~

-50

V

e

8 -100

V

<;;
Q.

~

C

1-150

V

V

/

V

./

-200

o

o

30

15

45

-250
-12

-10

t-Time-Ils
FIGURE 13

2-26

-8
-4
-6
VI-Input Voltage-V
FIGURE 14

TEXAS . "

INSTRUMENTS
POST OFFICE BOX 655012 • DALLAS, TEXAS 76285

-2

o

LM330
3·TERMINAL POSITIVE REGULATOR
TYPICAL CHARACTERISTICS
OUTPUT VOLTAGE

vs
REVERSE INPUT VOLTAGE

0.1

~

_J I =114~

R~ =;,
TJ

>

=25°C

CL = 10 /.IF

II'

0

I

l!

':i -0.1

\/

./

-

a.

~
~~

':i

I--

> -0.2

,"""-

1\

V

~

9o

LOAD TRANSIENT RESPONSE

~

.~

~

<{

I.,

...asas

::150

::J

Q

."
IV

.3
-10

-8

-6

0

o

o

-2

-4

CD
CD

.c

en

&:

U

-0.3
-12

...en

15

VI-Input Voltage-V

30
t-Tirne-/.Is

45

FIGURE 16

FIGURE 15
BIAS CURRENT
VS

OUTPUT CURRENT

35

V: = 1J V

30 f-TJ = 25°C

1 25
~

~ 20

:;

..
ffi
u

15

10
5

o

.........
o

",.,

V

30

........-

",.,

V

./"

",.,

V

60
90
120
IO-Output Current-rnA

,/

150

FIGURE 17

TEXAS •

INSTRUMENTS
POST OFFICE BOX 655012 • DALLAS, TEXAS 75265

2·27

LM330
3·TERMINAL POSITIVE REGULATOR
TYPICAL CHARACTERISTICS
BIAS CURRENT
vs
VIRTUALJUNCTION TEMPERATURE

24

J =114t
i' I I

21

IE

«

BIAS CURRENT
vs
INPUT VOLTAGE

40
I

IJ= 1150 LA

18

30

«

E

~

0

...

9

.!!!

II)

1:

!~

.~

!;

..

u

II)

E
I

15

~

~ 20

.
::I

U

10=50mA

III

iii

rn

6

CD
CD

3

:::r

10

16=6

...en

°

TJ =25 C

o
-60

I '-

10= 150 mA-

/ r\

L=50L-

T

/'
-40
o
40
80
120
TJ-Virtual Junction Temperature-oC

o

160

o

5

FIGURE 18

10
10
20
15
VI-Input Voltage-V

0
25

30

FIGURE 19

TYPICAL APPLICATION DATA
LM330

auTPuT .......---4t-- Va

VI----.---~INPUT

C1 = 0.1 /IF
(See Note A)

1

GND

1

C2 = 10/lF
(See Note B)

NOTES: A. Use of C1 is required if the regulator is not located in close proximity to the supply filter.
B. Capacitor C2 must be located as close as possible to the regulator and may be an aluminum or tantalum type capacitor. The
minimum capacitance that will provide stability is 1O-ItF. The capacitor must be rated for operation at - 40°C to assure stability

to that extreme.

FIGURE 20

2·28

TEXAS . "

INSTRUMENTS
POST OFFICE BOX 656012 • DALLAS, TEXAS 75265

LM2930-S, LM2930-8
3-TERMINAL POSITIVE REGULATORS
D2733 APRIL 1983-REVISED JUNE 1988

•

Input-Output Differential Less than 0.6 V

•

Output Current of 150 rnA

•

Reverse Battery Protection

KC PACKAGE
ITOP VIEW)

•

line Transient Protection

•

40-V Load-Dump Protection

•

Internal Short Circuit Current Limiting

•

Internal Thermal Overload Protection

•

Mirror-Image Insertion Protection

•

Direct Replacement for National LM2930
Series

THE COMMON TERMINAL IS IN
ELECTRICAL CONTACT WITH
THE MOUNTING BASE
TO·220AB

•

~'

description

...
II)

Q)
Q)

.c

The LM2930-5 and LM2930-8 are 3-terminal
positive regulators that provide fixed 5-V and
8-V regulated outputs. Each features the ability
to source 1 50 mA of output current with an
input-output differential of 0.6 V or less. Familiar
regulator features such as current limit and
thermal overload protection are also provided.

en

...
CO

LP
SILECT PACKAGE
ITOP VIEW)

GJ

The LM2930 series has low voltage dropout
making it useful for certain battery applications.
For example, the low voltage dropout feature
allows a longer battery discharge before the
output falls out of regulation; the battery
supplying the regulator input voltage may
discharge to 5.6 V and still properly regulate the
system and load voltage. Supporting this
feature, the LM2930 series protects both itself
and the regulated system from reverse battery
installation or 2-battery jumps.

d

INPUT

[j

COMMON

[]

OUTPUT

TO·226AA

CO

C

,
OCI

Other protection features include line transient
protection for load-dump of up to 40 V. In this
case, the regulator shuts down to avoid
damaging internal and external circuits. The
LM2930 series regulator cannot be harmed by
temporary mirror-image insertion.

PRODUCTION DATA dooumentsoontain information

curnnt I. of p.blication dal8. Products conform to
spacifications per the tarms of TexIs Instruments

:~~~:~i~·ir::I-:li ~:~:~ti:.n :.r::;:::~~

nat

TEXAS

~

INSTRUMENTS
POST OFFICE BOX 655012 • OALLAS, TEXAS 75265

Copyright © 1983, Texas Instruments Incorporated

2-29

LM2930·5. LM2930·8
3·TERMINAL POSITIVE REGULATORS
schematic diagram

3 kO

FOR
5V

COMMON~--~--~----~~--~--~~------------+-~----~+-~----~~----~

All component values are nominal.

absolute maximum ratings over operating free-air temperature range (unless otherwise noted)
Continuous input voltage .................................................... 26 V
Transient input voltage: t = 1 s .............................................. 40 V
Continuous reverse input voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. - 6 V
Transient reverse input voltage: t = 100 ms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. - 12 V
Continuous total dissipation (see Note 1) ..................... See Dissipation Rating Table 1
Continuous total dissipation (see Note 1) ..................... See Dissipation Rating Table 2
Operating free-air. case. or virtual junction temperature .................... -40°C to 150°C
Storage temperature range ......................................... - 65°C to 150°C
Lead temperature 1.6 mm (1/16 inch) from case for 10 seconds ..................... 260°C
NOTE 1: To avoid exceeding the design maximum virtual junction temperature, these ratings should not be exceeded. Due to variation
in individual device electrical characteristics and thermal resistance, the built·in thermal overload protection may be activated
at power levels slightly above or below the rated dissipation.
DISSIPATION RATING TABLE 1-fREE-AIR TEMPERATURE
PACKAGE
KC

LP

2-30

TA :s 25·C
POWER RATING
2000 mW
775mW

DERATING
fACTOR
16 mW'oC
6.2 mW'oC

DERATE
ABOVE TA

25°C
25°C

··· TEXAS ~
INSTRUMENlS
POST OFFICE BOX 665012 • DALLAS, TEXAS 75265

TA - 70·C
POWER RATING
1280 mW
496 mW

LM293D·5. LM293D·8
3·TERMINAL POSITIVE REGULATORS
DISSIPATION RATING TABLE 2-CASE TEMPERATURE
TC "'25°C
POWER RATING

DERATING

DERATE

FACTOR

ABOVE TC

Ke

20 W

LP

1600 mW

0.25 w/oe
28.6 mW/oe

PACKAGE

70 0

TC - 125°C
POWER RATING

e

6.25 W

94°e

715mW

recommended operating conditions
MIN

MAX
150

Output current

-40

Operating virtual junction temperature

125

LM2930·5 electrical characteristics at 25 °C virtual junction temperature. VI .. 14 V. 10 .. 150 mA.
(unless otherwise noted)
TEST CONDITIONS t

PARAMETER

Output voltage

VI = 6 V to 26 V,
TJ = -40 oe to 125°e

Input regulation

10 = 5 mA

Ripple rejection

I = 120 Hz

MIN

TYP

MAX

4.5

5

5.5

= 9 V to 16 V

7

25

= 6 V to 26 V

30

80

10 = 5 mA to 150 mA,

I VI
I VI

56

Output regulation

10 = 5 mA to 150 mA

14

Output voltage long-term drilt~

Alter 1000 h at TJ = 125°e

20
0.32

Dropout voltage

10 = 150 mA

Output noise voltage
Output voltage during

I = 10 Hz to 100 kHz

line transients
Output impedance

Bias current

VI = -12Vt040V,

RL - 100 Il

-0.3

50
0.6

.c

en

...caca

mV

C

mV
V

p.V
5.5

200

V

Mil

4

7

10 = 150 mA

18

40

300

700

150

CI)
CI)

V

mV

10=10mA

Peak output current

II)

dB

60

10 = 100 mA, 10 = 10 mA (rms}. 100 Hz to 10 kHz

...

UNIT

mA
mA

tPulse testing techniques are used to maintain the junction temperature as close to the ambient temperature as possible. Thermal effects
must be taken into account separately. All characteristics are measured with a O. 1-I'F capacitor across the input and a 10-I'F capacitor
across the output.
~Since long-term drift cannot be measured on the individual devices prior to shipment, this specification is intended to be an engineering
estimate of the average drift to be expected from lot to lot.

TEXAS •

INSTRUMENTS
POST OFFICE BOX 655012 • DALLAS. TEXAS 75266

2-31

LM293D·5, LM293D·8
3·TERMINAL POSITIVE REGULATORS
LM2930-8 electrical characteristics at 25°C virtual junction temperature. VI - 14 V. 10 - 150 rnA.
(unless otherwise noted)
PARAMETER

TEST CONDITIONSt
VI

Output voltage

TJ

10

Ripple rejection

I

Output regulation

10

Output voltage long-term driftt

Alter 1000 h at TJ

Dropout voltage

10 = 150 mA
1- 10 Hz to 100 kHz

Output voltage during
line transients

...

I»
I»
fJ)

Output impedance
Bias current

-:r
CD
CD

...en

=

5mA

= 120 Hz
= 5 mA to

VI

=

10
10
10

=
=
=

10

=

5 mA to 150 mA,

MIN

TVP

MAX

7.2

8

8.8

12

50

50
52

100

25

50

I VI = 9.4 V to 16 V
I VI = 9.4 V to 26 V

Input regulation

Output noise voltage

C

= 6 V to 26 V,
= -40°C to 125°C

150 mA

=

125°C

-12Vt040V,
l00mA,lo

=

RL

=

-0.3

100 II

=

100 Hz to 10 kHz

150

Peak output current

mV
V
~V

8.B

V

4
18

7
40

mA

300

700

mA

300

10mA
150 mA

mV

mV
0.6

90

10 mA (rms), I

V

dB

30
0.32

UNIT

Mil

t Pulse testing techniques are used to maintain the junction temperature as close to the ambient temperature as possible. Thermal effects

must be taken into account separately. All characteristics are measured with a O. l-I'F capacitor across the input and a 10-I'F capacitor
across the output.
*Since long-term drift cannot be measured on the individual devices prior to shipment, this specification is intended to be an engineering

estimate of the average drift to be expected from lot to lot.

TYPICAL CHARACTERISTICS
LM2930-5
OUTPUT VOLTAGE
vs
INPUT VOLTAGE

NORMALIZED OUTPUT VOLTAGE
vs
VIRTUAL JUNCTION TEMPERATURE
8

1.005

RL - 100 !l
7
1.000

t

~...

0.995

e
o

/'"

.......

/'"

"'" ~

:::I

>

.,I
l!!'"
0
>
...

~

] 0.990

5

:::I

4

0

3

So
:::I

""

ii
E

6

I

0

>

is

z 0.985

2

VI = 14V

I I

0.980
-60 -40 -20 0

0
20 40

60 80 100 120 140

0

FIGURE 1

2-32

15

30

VI-Input Voltage-V

T J-Virtual Junction Temperature-0 C

FIGURE 2

TEXAS

~

INSTRUMENTS
POST OFFICE BOX 655012 • DALLAS, TEXAS 75265

45

60

LM2930-5. LM2930-8
3-TERMINAL POSITIVE REGULATORS

TYPICAL CHARACTERISTICS
LM2930-5
OUTPUT VOLTAGE
vs
INPUT VOLTAGE
6.0

80

-I~ = 1~0 JA

5.0

/

"

C>

4.0

/

>
~

"a.
I

>

/
2.0

V

"""-

~

~ 50

u

';;' 40

a:

" 30
C.
.S!-

/

a:

20

10

o
3.0
4.0
5.0
VI-Input Voltage-V

6.0

10

1

100
lk
10k
f-Frequency-Hz

0.6

.1

_VI-Va = 9V
fa = 120 Hz
60
al
"C

I

"o
"t;

--

0.5

-

::;- 0.4

.,

C>

!3
'0

>

';;' 40

a:

0.3

"o
a.

"
C.
.S!-

~

a:

0.2

20

0.1

..---- -- -

---

..--

-

~

o

o

1M

DROPOUT VOLTAGE
vs
VIRTUAL JUNCTION TEMPERATURE

RIPPLE REJECTION
vs
OUTPUT CURRENT

1

lOOk

FIGURE 4

FIGURE 3

80

Ell

7
'\.v

'"

o
.;:

I
2.0

I

"C

/

1.0

\

60
al

/

8 3.0
o

I

la = 50 rnA
70 '-VI- Va=9V

>I
~

RIPPLE REJECTION
vs
FREQUENCY

50

150

100

la-autput Current-rnA

o

o

la = 150 rnA

la -150 rnA

la- 10 rnA

I

100
125
50
75
T J-Virtual Junction Ternperature-OC
25

150

FIGURE 6

FIGURE 5

TEXAS

~

INSTRUMENTS
POST OFFICE BOX 655012. DALLAS, TEXAS 75265

2-33

LM2930-5, LM2930-8
3-TERMINAL POSITIVE REGULATORS
TYPICAL CHARACTERISTICS
DROPOUT VOLTAGE
vs
OUTPUT CURRENT
0.6

OUTPUT IMPEDANCE
vs
FREQUENCY
10

l
TJ = 25 C
I

50 rnA
25°C

10
TJ

0.5

0
m
r+
m
(J)

"0

>

..
c

1.§

./

0.3

~

::I

...
0

/'"

d 0.2

=:r
CD
CD

0.1

/'

r+

en

o

I~

11l

=t 0.4
"
l!!'"

/'

/'"

I

V

~

::I

5'
o

V

0.1

0.01

o

50

100

150

1

200

10

Rl ~ 100!l
TJ ~ 25°C

'\

c(

f \

r

20

~

::I
u 15

5

1

cil = ~OJF-

TJ=25°C
10 = 150 rnA

...c

/

10

V "

1\

!\ /
\/

V

1\ /
\/

>I

.

~

~

5

~

o

"T

3

~

5.c

35

40

45

50

55

>

0

o

15

30
t-Tirne-/Js

VI-Input Voltage-V

FIGURE 9

2-34

1M

LINE TRANSIENT RESPONSE

25

.!.c

100k

FIGURE 8

INPUT CURRENT
vs
INPUT VOLTAGE

E

10k

f-Frequency-Hz

FIGURE 7

30

1k

100

10-Output Current-rnA

FIGURE 10

TEXAS ~

INSTRUMENTS
POST OFFICE BOX 655012 • DALLAS, TEXAS 75265

45

LM2930·5, LM2930·8
3·TERMINAL POSITIVE REGULATORS
TYPICAL CHARACTERISTICS
OUTPUT VOLTAGE
vs
REVERSE INPUT VOLTAGE

INPUT CURRENT
vs
REVERSE INPUT VOLTAGE
50

0.1

°

I

I I
RL=oo
TJ = 25°C

TJ = 25 C

o

«
E
.!.I:

a

-50

~

-100

:>Co

/

I:

I

-150

./'

v

/

V
/'

V

>

0

I

~

!l

~

:>

so"
I

-0.1

- -I-

o
> -0.2

til
...

V

,/

en

~~

Q)
Q)
~

CJ)

...asas

-200

C
-250
-12

-10

-8
-4
-6
VI-Input Voltage-V

-2

-0.3
-12

o

-8
-6
-4
VI-Input Voltage-V

-10

FIGURE 11

FIGURE 12
BIAS CURRENT
vs
OUTPUT CURRENT

LOAD TRANSIENT RESPONSE

.
I>

~...

T

l£!i

«

E 25

~

>

~

v!=1L
30 -TJ = 25°C

I f'.

0

::::I .~

o

35

JI-JO~ 9J
40 r- CL = 10 IIF

I:

a.2

... ...

I

\I

-40

1:
~ 20

.."

0

.,/

~

.
o
..
.3

.

~~

«
E
.!.I:

iii 15

.-/

10

~ 150

5

"C

0

o

o

-2

15

30
t-Time-II S

45

o

V

.......

o

,.......- V

30

V

V ""

""

60
120
90
IO-Output Current-mA

150

FIGURE 14

FIGURE 13

TEXAS . "

INSTRUMENTS
POST OFFICE BOX 655012 • DALLAS. TEXAS 75265

2·35

LM2930·S, LM2930·8
3·TERMINAL POSITIVE REGULATORS
TYPICAL CHARACTERISTICS
LM2905-5
BIAS CURRENT
vs
INPUT VOLTAGE

BIAS CURRENT
vs
VIRTUAL JUNCTION TEMPERATURE
24

40
VI - 14 V

-I

21

I I

ct

TJ - 25·C

1 1

J

-

18 1-10 ~ 150 mil.

30
ct

E

E

I

C

II)

r+

II)

en

:::r

E 15

~
::l
u

.

II)

I

E
! 20

~

9

:;

.

10 - 50 mA

II)

iii

6

CD
CD

I

I

r+

10

150mA-

I

10 = 5 0 m A -

/ \.

3

/'

o

o
-60

=

I

iii
10 - 0

en

10

"-

(

U

o

-40

40

80

120
TJ-Virtual Junction Temperature-·C

160

10

o

10

5

15

20

=

0
25

30

VI-Input Voltage-V

FIGURE 16

FIGURE 15

TYPICAL APPLICATION DATA
LM2930

VI--~-~INPUT

C1 - 0_1

~F

(See Note AI

I

OUTPUT I - - - - - v o
C2 = 10

I

COMMON

~F

(See Note BI

NOTES: A. Use of C1 is required if the regulator is not located in close proximity to the supply filter.
B. Capacitor C2 must be located as close as possible to the regulator and may be an aluminum or tantalum type capacitor. The
minimum value required for stability is 10 I'F. The capacitor must be rated for operation at - 40
to guarantee stability to

ac

that extreme.

FIGURE 17

2-36

TEXAS

~

INSTRUMENTS
POST OFFICE BOX 655012 • DALLAS, TeXAS 75265

LM2931-5AQ
3-TERMINAL POSITIVE VOLTAGE REGULATOR
02828, AUGUST 1988-REVISED OCT08ER 1988

•

Input-Output Differential Less than 0.6 V

•

Internal Short-Circuit Current Limiting

•

Output Current of 150 rnA

•

Internal Thermal Overload Protection

•

Reverse Battery Protection

•

Mirror-Image Insertion Protection

•

Very Low Quiescent Current

•

Reverse Transient Protection

•

60-V Load-Dump Protection

•

Direct Improved Replacement for National
LM2931-5 and LM2931A-5

LP
SILECT PACKAGE

QJ:!:}

D
SMALL·OUTLINE PACKAGE

(TOP VIEWI

U

US
(TOP VIEWI

OUTPUT
COMMON

INPUT
COMMON
OUTPUT

II
...

KC PACKAGE
(TOP VIEW)

2

7

INPUT
COMMON

COMMON

3

6

COMMON

NC

4

5

NC

TO·226AA

~

en

OUTPUT

~COMMON

Q)
Q)

INPUT

.c:
en

THE COMMON TERMINAL IS IN
ELECTRICAL CONTACT WITH
THE MOUNTING BASE

...'"

TO·220AB

'"

C

,

•

OCI

description
The LM2931-5AQ is a 3-terminal pOSitive voltage regulator that provides a 5-V regulated output. It features
the ability to source 150 rnA of output current with an input-output differential of 0.6 V or less. Familiar
regulator features such as current limit and thermal overload protection are also provided.
This device also has a low dropout voltage making it useful for certain battery applications. For example,
because the low dropout voltage allows a longer battery discharge before the output falls out of regulation,
the battery supplying the regulator input voltage may discharge to 5.6 V and still properly regulate the
5-V load voltage. Supporting this feature, the LM2931-5AQ protects both itself and the regulated system
from reverse battery installation or 2-battery jumps. The very low quiescent current feature is especially
useful in battery-powered applications.
Other protection features include line transient protection from load-dump of up to 60 V. In this case, the
regulator shuts down to avoid damaging internal and external circuits. The LM2931-5AQ regulator is virtually
immune to temporary mirror-image insertion.
The Q suffix indicates that the device is characterized for operation from - 40 DC to 125 DC.

PRODUCTION DATA dooumont. oonllin inform..io.
currant I. of publication data. Preducts conform to
specifications par til, tarms of TaxIS Instruments

=~~;·i:I:r~ =::i~n :.r:::::£::~

not

.

TEXAS

~

INSTRUMENlS
POST OFFICE BOX 655012 • DALLAS, TEXAS 75265

Copyright © 1988. Texas Instruments Incorporated

2-37

LM2931·5AQ
3·TERMINAL POSITIVE VOLTAGE REGULATOR
absolute maximum ratings over operating junction temperature range (unless otherwise noted)
Continuous input voltage. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 26 V
Transient input voltage: t = 1 s . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 60 V
Continuous reverse input voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. - 15 V
Transient reverse input voltage: t = 100 ms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. - 50 V
Continuous total dissipation (see Note 1) . . . . . . . . . . . . . . .. See Dissipation Rating Tables 1 and 2
Operating virtual junction temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. - 40°C to 125°C
Storage temperature range ......................................... -65°C to 150°C
Lead temperature 1,6 mm (1/16 inch) from case for 10 seconds ...................... 260°C

E

NOTE 1: To avoid exceeding the design maximum virtual junction temperature, these ratings should not be exceeded. Due to variation
in individual device electrical characteristics and thermal resistance, the built-in thermal overload protection may be activated
at power levels slightly above or below the rated dissipation.

DISSIPATION RATING TABLE 1 - FREE-AIR TEMPERATURE

C

I»
r+
I»

DERATING FACTOR
TA '" 2SoC
POWER RATING ABOVE TA - 2SoC
6.6 mW/oC
825 mW
16 mW/oC
2000 mW

PACKAGE

en
::r

0
KC

CD
CD

LP

775 mW

TA - 12SoC
POWER RATING
165 mW
400mW

6.2 mW/oC

155 mW

r+

(II

DISSIPATION RATING TABLE 2 - CASE TEMPERATURE
PACKAGE

TC '" 25°C
POWER RATING

o

1600 mW

KC
LP

20 W
1600 mW

DERATING
FACTOR
29.4 mW/oC

DERATE
ABOVE TC

0.18 W/oC

39°C

4.5W

28.6 mW/oC

94°C

715 mW

96°C

TC - 125°C
POWER RATING
735 mW

recommended operating conditions
MIN

MAX

-40

150
125

Output current, 10
Operating virtual junction temperature, T J

electrical characteristics at 25°C virtual junction temperature, VI
PARAMETER
Output voltage

TEST CONDITIONSt
VI - 6 V to 26 V, 10 '" 150 mA,
TJ = -40°C to 125°C
10 = 10 mA

Ripple rejection

10 = 10 mA, I = 120 hz
10 - 5 mA to 150 mA

Output voltage long-term drilt*
Dropout voltage

MIN

TYP

MAX

UNIT

4.75

5

5.25

V

2
4

10
30

mV

80
14

50

mV

20
0.05

0.2

0.3

0.6

IVI=9Vt016V
I VI = 6 V to 26 V

Input regulation

Output regulation

14 V (unless otherwise noted)

10 = 10 mA, Alter 1000 h at TJ = 125°C
10 - 10mA

Output noise voltage

10 = 150 mA
10 = 10mA, 1= 10 Hz to 100 kHz

Bias current

TJ = = -40°C to 125°C

VI = 6 V to 26 V, 10 = 10 mA,
VI = 14 V, 10 = 150 mA, TJ - 25°C

60

dB
mV

500

V

IlV rms

0.4

1

10

12

mA

t Pulse testing techniques are used to maintain the junction temperature as close to the ambient temperature as possible. Thermal effects

t

2-38

must be taken into account separately. All characteristics are measured with a O.1-p.F capacitor across the input to common and a 100-p.F
capacitor, with equivalent series resistance of less then 1 0, across the output to common.
Since long-term drift cannot be measured on the individual devices prior to shipment, this specification is not intended to be a guarantee
or warranty. It is an engineering estimate of the average drift to be expected from lot to lot.

TEXAS •

INSTRUMENlS
POST OFFICE BOX 655012 • DALLAS. TEXAS 75265

LT1004
MICROPOWER INTEGRATED VOLTAGE REFERENCE
03190, JANUARY 1989

• Initial Accuracy ...
±4 mV for LT1004-1.2
±20 mV for LT1004-2.5

LT1004C ... 0 PACKAGE
(TOPVIEWI

NC[]8
NC 2
7
NC 3
6
ANODE 4
5

• Micropower Operation
• Operates Up to 20 mA

CATHODE
NC
CATHODE
NC

• Very Low Reference Impedance
NC ~ No internal connection

• Applications:
Portable Meter References
Portable Test Instruments
Battery Operated Systems
Current-Loop Instrumentation

LT1004M. LT1004C ... LO PACKAGE

8

II
...

ITOP VIEW)

CAT'OO'

,'escription

CI)

Q)

The LT1 004 micropower voltage references are
two-terminal
bandgap
reference
diodes
designed to provide high accuracy and excellent
temperature characteristics at very low operating
currents. Optimizing the key parameters in the
design, processing, and testing of the devices
results in specifications previously attainable
only with selected units.
The LT1004 is a pin-for-pin replacement for the
LM185 series of references with improved
specifications. The LT1 004 is an attractive device
for use in systems in which accuracy was
previously attained at the expense of power
consumption and trimming.

en

,"00,

.c
tn

The anode is in electrical contact with the case.

...
C'a
C'a

LT1 004C ... LP PACKAGE
(TOP VIEW)

"

"
""
""

C

ANODE
CATHODE
NC

NC - No internal connection

symbol
ANODE

--i~"'L-- CATHODE

The LT1004M is characterized for operation over
the full military temperature range of -55°C
to 125°C. The LT1004e is characterized for
operation from ooe to 70°C.
AVAILABLE OPTIONS
PACKAGE
TA
O°C
to
70°C
-55°C
to
125°C

NOM
Vz

SMALL OUTLINE

METAL CAN

(D)

(LD)

(LP)

1.2V

LTl 004CD-l .2

LTl 004CLD-l.2

LTl004CLp·l.2

2.5V

LTl004CD-2.5

LT1004CLD-2.5

LTl 004CLP·2.5

1.2 V

LT1004MLD-l.2

2.5 V

LT1004MLD-2.5

PLASTIC

The D package is available taped and reeled. Add suffix R to the device type {i.e.,
LTl004CDRO.

PRODUCTION DATA do.ume....ontoin information
currant 8S of publication data. Products conform to
specifications par the terms of Taxas Instruments
standard warranty. Production p:roclssing dOBS nat
necessarily include testing of an parameters.

Copyright @ 1989. Texas Instruments Incorporated

TEXAS ",
INSTRUMENTS
POST OFFICE BOX 655012 • DAl.LAS, TEXAS 75265

2-39

LT1004
MICROPOWER INTEGRATED VOLTAGE REFERENCE
schematic
LT1004-1.2

CATHODE

200 k{!

•

01

50 k{!

C

I»
r+
I»
(J)
::T
CD
CD

300 kO

r+

014

(I)

60 k{!

ANODE
LT1004-2.5
r -__~__~~__~______~~~__~____~~~~C~A~THODE

7.5 kO

200 kD

500 kO
01

50 k{!

500 kO

014

500 kO
60 kO

ANODE

All component values shown are nominal.

2-40

TEXAS ."

INSTRUMENTS
POST OFFICE BOX 655012 • DALLAS, TeXAS 75265

LT1004
MICROPOWER INTEGRATED VOLTAGE REFERENCE
absolute maximum ratings over operating free-air temperature range
Reverse current . . . . . . . . . . . . . . . . . . . . . . . .
Forward current . . . . . . . . . . . . . . . . . . . . . . . .
Operating free-air temperature range: LT1004M . .
LT1004C . .
Storage temperature range .. . . . . . . . . . . . . . .
Lead temperature 1,6 mm (1/16 inch) from case for
Lead temperature 1,6 mm (1/16 inch) from case for

.........
.........
.........
.........
....... ..
10 seconds:
10 seconds:

. . . . . . . . . . . . . . . . . . . . . . .. 30 mA
. . . . . . . . . . . . . . . . . . . . . . .. 10 mA
. . . . . . . . . . . . . . . .. -55'e to 125°C
. . . . . . . . . . . . . . . . . . .. ooe to 70°C
. . . . . . . . . . . . . . . .. -65'e to 150°C
D or LP package . . . . . . . . . .. 260°C
LD package .............. 300°C

•

electrical characteristics at specified free-air temperature
PARAMETER

Vz

CJ.vz

flV z

Reference voltage
Average temperature
coefficient of reference
voltage*
Change in reference
voltage with current

TEST CONDITIONS
Iz = 100!lA.
See Note 1
Iz = 10

Long-term change in
reference voltage

IZ(min)

Minimum reference
current

LT1004-2.5

TYP

MAX

MIN

TYP

MAX

25'C

1.231

1.235

1.239

2.48

2.5

2.52

O'C to 70'C
- 55'C to 125'C

1.225

1.245

2.47

2.53

1.22

1.245

2.46

2.535

UNIT

....
II)

V

Q)
Q)

..c

20
25'C

I1A to 1 rnA

Iz = 1 rnA to 20 rnA
flVdflt

LT1004-1.2
MIN

I1A

Iz = 2O!lA
Iz = 10

TAt

Iz = 1OO!lA

25'C
Full range

1
1.5

25'C

10

1.5
10

Full range

20

20

25'C
Full range
25'C

Zz

Reference impedance

Iz = 1OO !lA

Vn

Broadband noise
voltage

Iz - 100 !lA,
f= 10Hzt010kHz

20

25'C

10

12

20

0.6

0.2

0.6

1.5

C

mV

ppm/khr

20

8

60

....COCO

1

0.2

Full range

en

ppml"C

20

1.5
120

I1A
fl

!lV

t Full range is -55'C to 125'C for the LT1004M and O'C to 70'C for the LT1004C.
* The average temperature coefficient of reference voltage is defined as the total change in reference voltage divided by the specified
temperature range.

NOTE 1: The O'C to 70'C limits apply for both M- and C-suffix devices. The -55'C to 125'C limits apply only for M-suffix devices.

TEXAS ."

INSTRUMENTS
POST OFFICE BOX 655012 • DAllAS. TEXAS 75265

2-41

LT1004-1.2

MICROPOWER INTEGRATED VOLTAGE REFERENCE
TYPICAL CHARACTERISTICSt
REFERENCE VOLTAGE CHANGE
vs
REVERSE CURRENT

REVERSE CHARACTERISTICS
100

16
TA - -55°C to 125°C

I

TA - -55°C to 125°C

>

E
! 12
c

..

.'"
.
'"
>
."

...

«I:

I 10

~

"

()

c

51

.
~

Q)

r+
Q)

II:

en
::r

.!f.

/

I

CD
CD

r+

til

0.1

I

J:
()

E

o

/

V

V

[f

~

~

0

c

4

!

V
0.2

8

CD

t,..-I..;

li

II:

I

0

N

>
- 1.240

l/

>
I

~

.
I

0.8

l!

'"
~

VV

"0

>

"E.,

~ 1.235

g

I-

~

[7

!

.:?

o

i

100

10

IR-Reverse Current-rnA

V

-r-..,

I---

r-.......

~ 1.230
I

0.4

u..

>

~

N

>

1.225

o
0.01

0.1

10

100

- 55 - 35 - 15

IF-Forward Current-rnA

5

25

45

65

85 105 125

T A - Free-Air Ternperature- °C

FIGURE 3

FIGURE 4

t Data at high and low temperatures are applicable only within the rated operating free-air temperature ranges of the various devices.

2-42

TEXAS

~

INSTRUMENTS
POST OFFICE BOX 655012. DALLAS, TEXAS 75265

LT1 004.-1.2

MICROPOWER INTEGRATED VOLTAGE REFERENCE
TYPICAL CHARACTERISTICS
REFERENCE IMPEDANCE
vs
FREQUENCY

REFERENCE IMPEDANCE
vs
REFERENCE CURRENT
100

c:

.,
1

gIII

10

.,Co

10 k

t':'::25Hz '"''
TA = -55°C to 125°C

Iz - 100 p.A
TA = 25°C

~

.,1
"

I:
III

1\

"tJ

il

100

Co

.§

.§

.,
"f

~

I:

I!!
.!
.,
a:

-ta:

....

I

"

10

N

N

r--..
0.1
0.01

10

0.1

...
CO
CO

C
0.1

FIGURE 6
OUTPUT NOISE VOLTAGE
vs
CUTOFF FREQUENCY
70

~ ~~II~A

600 TA - 25°C

I:

I

~ 400
III

60

>"-

.,
I

"

l!l'"

"0

>.,

..

......

!::

o

~ 300

..

·0
2:

·0

1 1 1fll

IIII

50
40

1 k

10 k

",

,/

...

100 p.A

-

30

10

o
100

Il~lOIW~m

1= 116d I~

P

I

/

0

\

100

10

1
z

:;
Co
:; 20

~ 200
I:
>

1000

f - Frequency - kHz

NOISE VOLTAGE
vs
FREQUENCY

~> 500

100

10

FIGURE 5

I z1=1

CI)

Q)
Q)

J:

Iz-Reference Current-rnA

700

...

(/J

0.1
0.01

100

/

/

I

N

,/

-

/v
V

c: 1 k

100 k

"7

"

o
10

0.1

f-Frequency-Hz

100

f-Cutoff Frequency-kHz

FIGURE 8

FIGURE 7

TEXAS •
INSTRUMENTS
POST OFFICE BOX 655012 • DALLAS, TEXAS 75265

2-43

LT1004-2.5
MICROPOWER INTEGRATED VOLTAGE REFERENCE
TYPICAL CHARACTERISTICSt
REVERSE CHARACTERISTICS

FORWARD CHARACTERISTICS

100

1.2
TA -

1
I

C

10

j

j

C

m
r+
m
en
=s-

(

I

IE

CD
CD

0.1

r+

tn

-55°C to 125°C

o

V

0.5

/

T~

'.'

~~'~C

>

.
I

.---

-i'"

0.8

>

'"

.

"E
~

-I-'"

...I 0.4
...
>
0

2

1.5

2.5

o

3

0.01

0.1

VR-Reverse Voltege-V

10

IF-Forward Current-mA

FIGURE 9

FIGURE 10
REFERENCE VOLTAGE
vs
FREE-AIR TEMPERATURE

2.515

>

.
go

2.510

>

2.500

I

-a

2.505

g! 2.495

jI

2.490

./

-.....

v

I'-...

/

.; 2.485

""

2.480
-55-35 -15

5

25

45

65

85 105 125

TA-Free-Alr Tamperature- °C

FIGURE 11
t Data at high and low temperatures are applicable only within the rated operating free-air temperature ranges of the various devices.

2-44

TEXAS . "

INSlRUMENTS
POST OFFICE BOX 655012 • DALLAS, TEXAS 76265

100

LT1004-2.5
MICRO POWER INTEGRATED VOLTAGE REFERENCE
TYPICAL CHARACTERISTICS
REFERENCE IMPEDANCE
vs
REFERENCE CURRENT
1000

= 25 H~'

f

TA

=

REFERENCE IMPEDANCE
vs
FREQUENCY
10 k

""

Iz - 100 "A
TA - 25°C

-55°C to 125°C

c:

c: 1k

.,I
.,"c

~ 100
c

.,"

ilQ.

.E

""c
~
~
.,

~ 100

\

10

.E.,

"~
~"

a:
I

0.1
0.01

0.1

0.1

10

100

1000

120
Iz

~ i061,,~

~ 100
I

"
-~

"-

~

800

RC LOW PASS ~
80

ill

......

;g

"0

600

60

-

40

-

~

::J

"
·0

So

II)

6

~ 400

."

\

c

>

~

~

u::

200

o
10

..

FILTERED OUTPUT NOISE VOLTAGE
vs
CUTOFF FREQUENCY

Iz = 100 "A
TA = 25°C

J!!

>

en

FIGURE 13

1200

:g,

.r:.

f-Frequency-kHz

NOISE VOLTAGE
vs
FREQUENCY

c
I

Q)
Q)

ca
ca
C

FIGURE 12

~> 1000

In

'/

Iz-Reference Current-rnA

1400

II
..

/

/

/

0.1
0.01

100

10

/

10

I
~

r-.

N

N

V

/

20

o
100

1 k

10 k

100 k

ts,
..

-

/
l/V

/

0.1

f- Frequency - Hz

10

100

f - Cutoff Frequency - kHz

FIGURE 14

FIGURE 15

TEXAS •
INSTRUMENTS
POST OFFICE BOX 655012 • DALLAS, TEXAS 75265

2-45

LT1004
MICROPOWER INTEGRATED VOLTAGE REFERENCE
TYPICAL CHARACTERISTICS
LT1004-'_2

LT1004-2_5

TRANSIENT RESPONSE

TRANSIENT RESPONSE

>

>

I 1.5

•

i

1

&.

0.5

o

0

OUTPUT

/

I

i

'y-

V VI~1"VO

.

...
.5
~

o

~
o

o

11

•

..

INPUT

o

OUTPUT
'y-

24 kO I
VI,VO

•
INPr

o
100

500

600

100
t-Time-Its

t-Time-Its

FIGURE 16

2-46

l.A

5

A

5

2

~

~

11

3

FIGURE 17

TEXAS ",
INSTRUMENTS
POST OFFICE BOX 655012 • DALLAS, TEXAS 75265

500

LT1004
MICROPOWER INTEGRATED VOLTAGE REFERENCE
TYPICAL APPLICATION DATA

24V
1600"8 RC
22 kll

\a .....

OUT

L]~~_

16.9 kll

LT1004-1.2

...en

1.05 kilt

Q)
Q)

10 kll

.c

LJ'TI-LINPUT

tn

...
CO
CO

-5V

C

t 1 % metal film resistors

FIGURE 18. Vpp GENERATOR FOR EPROMS (NO TRIM REQUIRED)
NETWORK DETAIL

RT Network

YSI44201

15V
2.7 kll
5%

0.1%
10 kll

276511
0.1%
0-10 V
0-100oC

LT1004·1.2

168.3
0.1%

0.1%
10 kll

FIGURE 19. O°C TO 100°C LINEAR OUTPUT THERMOMETER

TEXAS . "

INSTRUMENTS
POST OFFICE BOX 655012 • DALLAS, TEXAS 75265

2-47

LT1004

MICROPOWER INTEGRATED VOLTAGE REFERENCE
TYPICAL APPLICATION DATA
r:-:---------I,....VIN - 9 V to 15 V

5.6 kll

~-----I__----<"'VO

150 pF

LT1004·1.2

C

::r
CD
CD

r+
UI

3.01 Mil

1%

1 Mil

1%

I»
r+
I»
(f)

- 5V

FIGURE 20. MICROPOWER 5-V REFERENCE
9V

m::!r~I:~

~

10kll

-=-

1.235 V

LT1004·1.2

FIGURE 22. MICROPOWER REFERENCE FROM
9-VBATIERY

FIGURE 21. LOW-NOISE REFERENCE

100 kll

It

..

Rl
1684 II

3V _
LlTHIUM-

5 kll AT
25°C*

+
1800 II

+
THERMOCOUPLE
TYPE
t Quiescent current ~ 1 5 p.A

J

* Yellow Springs Inst. Co .• Part #44007
NOTE: This application compensates within ± 1 ·C from O·C
to SO·C.

K

T

s

FIGURE 23. MICROPOWER COLD-JUNCTION
COMPENSATION FOR THERMOCOUPLES

2-48

TEXAS . "

INSTRUMENTS
POST OFFICE BOX 655012 • DALLAS, TEXAS 75265

Rl
233 kll
299 kll
300 kll
2.1 Mil

LT1004
MICROPOWER INTEGRATED VOLTAGE REFERENCE
TYPICAL APPLICATION DATA
LT338A
OUT 1 - -.......- 5 V

VI ~ 8 V-'---IIN

t:

3000
1%

5V50kO

LT1004·2.5

2.5 V
1000
1%

-::- LT1004·2.5

FIGURE 24. 2.5-V REFERENCE

FIGURE 27. HIGH-STABILITY 5-V REGULATOR

15 V

----4t---+---VCC+ ~ 5 V

2 kOt

t---1=====OUTPUT
LT1004·1.2
Rl

(See Notel

10 (Se8 Notel
-5V
t May be increased for small output currents.

NOTE: Rl '"

2 V
• 10
10 + 10pA

~ 1.235

200 kO

60 kO
LT1004·1.2

V.

Rl

' - - - -....-VCC- '" -5V

-::-

FIGURE 25. GROUND-REFERENCED CURRENT
SOURCE

FIGURE 28. AMPLIFIER WITH CONSTANT GAIN
OVER TEMPERATURE
V+

1.5 V

~(S:
k:otel

R", 5 kO

1.235 V

10 (See Notel

-::- LT1004·1.2

NOTE:

Output regulates down to 1.285 V for 10

~

1.3 V
NOTE: 10 '" -R-

O.

FIGURE 26. 1.2-V REFERENCE FROM 1.5-V
BATIERY

FIGURE 29. 2-TERMINAL CURRENT SOURCE
WITH LOW TEMPERATURE COEFFICIENT

TEXAS

~

INSTRUMENTS
POST OFFICE BOX 655012 • DALLAS, TEXAS 75265

2·49

LT1004
MICROPOWER INTEGRATED VOLTAGE REFERENCE
TYPICAL APPLICATION DATA

.---_ _ _-+_ _._---e-BATTERY
OUTPUT

1 Mil

..=.. 12 V

~
LO - BATTERY LOW
133 kll
1%

LT1004-1.2

t Rl sets trip point. 60.4 kll per cell for 1.B V per cell.

C

...mm

FIGURE 30. LEAD-ACID LOW-BATIERY-VOLTAGE DETECTOR
LT33BA

en
::T
CD
CD

...

1 "F

+

120 Il

(I)

R1
2 kll
(See Notal

VeeNOTE: Rl

s Vee -

1

V

0.Q15

FIGURE 31. VARIABLE-VOLTAGE SUPPLY

2-50

TEXAS ."

INSTRUMENTS
POST OFFICE BOX 655012 • DALLAS. TEXAS 75265

LT1009
2.5-V INTEGRATED REFERENCE CIRCUIT
03191. MAY 1987-REVISEO

• Excellent Temperature Stability

1989

LT1009M. LT1009C ... LD PACKAGE
(TOP VIEW)

• Initial Tolerance ... 0.2% Max
• Dynamic Impedance ... 0.6 n Max
ADJ

• Wide Operating Current Range
• Directly Interchangeable with LM136

ANODE
CATHODE

• Needs No Adjustment for Minimum
Temperature Coefficient

The anode is in electrical contact with the case.
LT1009C ... LP PACKAGE
(TOP VIEW)

description
The LT1009 is a precision trimmed 2.5-V shunt
regulator featuring a maximum initial tolerance of
only ±5 mV, low dynamic impedance, and a
wide operating current range. The 0.2%
reference tolerance is achieved by on-chip
trimming, which minimizes the initial voltage
tolerance and the temperature coefficient OlVZ'

ANODE
CATHODE
ADJ

symbol

Even though the LT1009 needs no adjustments,
a third terminal allows the reference voltage to be
adjusted 5% to eliminate system errors. In many
applications, the LT1009 can be used as a pinfor-pin replacement for the LM136H-2.5, which
eliminates the external trim network.

ANOOE

II
...
II)

CI)
CI)

.c

en

r

CATHODE

...
C1:I
C1:I

C
ADJ

The uses of the LT1009 include a 5-V system
reference, an 8-bit ADC and DAC reference, or a
power supply monitor. The LT1009 can also be
used in applications such as digital voltmeters
and current-loop measurement and control
systems.
The LT1009M is characterized for operation over
the full military temperature range of -55°C
to 125°C. The LT1009C is characterized for
operation from O°C to 70°C.

Copyright © 1989, Texas Instruments Incorporated

PRODUCTION DATA documants contain information

currant as af publicltian data. Predacts conform to
specificatiDns par the tarms af TIllS Instruments

:::~:~~;8i::I-::ri =~::i:r :.r:::::~:~ nDt

TEXAS . "

INSTRUMENTS
POST OFFICE BOX 655012 • DALLAS, TEXAS 75265

2-51

LT1009
2.5-V INTEGRATED REFERENCE CIRCUIT
schematic
~----------------------------e-------------~'-~'---CATHODE

24 kll

24 kll

6.6 kll

E

720 II
~--e-------~~-------------------------4------~~--ANODE

All component values shown are nominal.

2-52

TEXAS ~

INSTRUMENTS
POST OFFICE BOX 655012 • DALLAS, TEXAS 76265

LT1009
2.5-V INTEGRATED REFERENCE CIRCUIT
absolute maximum ratings over operating free-air temperature range
Reverse current . . . . . . . . . . . . . . . . . . . . . . . .
Forward current . . . . . . . . . . . . . . . . . . . . . . . .
Operating free-air temperature range: LT1009M . .
LT100ge . .
Storage temperature range . . . . . . . . . . . . . . . .
Lead temperature 1,6 mm (1/16 inch) from case for
Lead temperature 1,6 mm (1/16 inch) from case for

.........
........ .
.........
.........
.........
10 seconds:
10 seconds:

.
.
.
.
.

. . . . . . . . . . . . . . . . . . . . . .. 20 mA
. . . . . . . . . . . . . . . . . . . . . .. 10 mA
. . . . . . . . . . . . . . .. -55°C to 125°C
. . . . . . . . . . . . . . . . . .. Qoe to 70°C
. . . . . . . . . . . . . . .. -65°C to 150°C
Dar LP package . . . . . . . . . .. 260°C
LD package .............. 300°C

electrical characteristics at specified free-air temperature
PARAMETER

TEST CONDITIONS

Vz
Reference voltage
Iz -1 mA
V
Change in reference
a z(temp) voltage with temperature

(Xvz

Average temperature
coeffiCilnt of reference
voltage

avz

Change in reference
voltage with current

Iz

~

400

avz/at

Long-term change in
reference voltage

Iz

~

I mA

Zz

Reference impedance

Iz = I mA

TAt
25'C

TYP

MAX

MIN

TYP

MAX

2.495

2.5

2.505

2.495

2.5

2.505

MIN to MAX

\lA to 10 mA

LT1009C

LT1009M
MIN

15

O'C to 70'C

15

25

- 55'C to I 25'C

25

35

25'C

2.6

6
10

Full range

25'C

20

25'C
Full range

0.3

4
15

I

V
mV

25
ppmrC

2.6

10
12

20
0.6

UNIT

0.3

mV
ppm/khr

1
1.4

...
II)

Q)
Q)

..s::::

en

...
CI:I
CI:I

C

n

t Full range is -55'C to I 25'C for the LTl009M and O'C to 70'C for the LTI009C.
t The average temperature coefficient of reference voltage is defined as the total change in reference voltage divided by the specified
temperature range.

TEXAS ."

INSTRUMENTS
POST OFFICE BOX 655012 • DALLAS, TEXAS 75265

2-53

LT1009
2.5-V INTEGRATED REFERENCE CIRCUIT
TYPICAL CHARACTERISTICSt
CHANGE IN REFERENCE VOLTAGE
vs
REFERENCE CURRENT

REFERENCE VOLTAGE
vs
FREE-AIR TEMPERATURE
2.53

>

E

.,I 4
'"
~
'0

2.52

>

.,I

i'

o

>.,

2.51

~

~

2.5

; j

I 2.49

"!c

- ---r--..... i'-..

V

/

en
::r::
CD
CD

/v

5

I
I z ·1mA

3

.,

';;

II:

.5 2

.,
'".c
z:

1/

()

I

2.48

N

>


/

V

V

1.0

V ....
V lt~J
·C

~~ t;. I---

~

t----

TJ

I 0.4 ~

--..b I

./

u..

>

0.2

.125 o

1.4
1.8
2.2
VR-Reverse Voltage-V

l.---'

V

2.6

o
0.001

0.01

0.1

IF-Forward Current-mA

FIGURE 3

FIGURE 4

t Data at the high and low temperatures are applicable only within the rated operating free-air temperature ranges of the various devices.

2-54

TEXAS . "

INSTRUMENTS
POST OFFICE BOX 655012 • DALLAS. TEXAS 75265

10

LT1009
2.5-V INTEGRATED REFERENCE CIRCUIT
TYPICAL CHARACTERISTICS
REFERENCE IMPEDANCE
vs
FREQUENCY

NOISE VOLTAGE
vs
FREQUENCY

100

250
Iz - 1 mA
TJ - 25°C

Iz -1mA
TJ - -55°C to 125°C

c:

~
~

I

8
i

1

10

200

\

I

1
.5
g

~
15

I

>

/

~

150

\

.!z

/

a:

\

I
.; 100

I

N

N

•
...
II)

'"

Q)
Q)

.........

J:

U)

...
CO
CO

C
0.1
0.01

0.1

10

50
10

100

100

f-Frequency-kHz

1k

10 k

100 k

f- Frequency - Hz

FIGURE 5

FIGURE 6
TRANSIENT RESPONSE

.

>

...
I

I

i/\

2.5

\1/

2

B1.5
"0

I-- I--

>

-

10 .5

c5

..,c

.

~

1

i

~
~ 5 kll

INPUT

0

1~ r ..

\

OU1PUT

-

~

"

Co

-=

OUTPUT

II

-

INPUT

4

o

-

I

8

o

I
20
t-Time-I's

FIGURE 7

TEXAS .."

INSTRUMENTS
POST OFFICE BOX 655012 • DALLAS, TEXAS 75265

2-55

LT1009
2.5-V INTEGRATED REFERENCE CIRCUIT
TYPICAL APPLICATION DATA

S

5 V-35 V

·6kll

LT1009

OUTPUT

10 kilt
TRIM

t Does not affect temperature coefficient. Provides ± 5% trim range.

c

...
D)

FIGURE B. 2.5-V REFERENCE
3.6 V TO 40 V

D)

en
::r
CD
CD

...

6211

III

~_ _"S10kll

FIGURE 9. ADJUSTABLE REFERENCE WITH WIDE-SUPPLY RANGE

I-"'--"'-VO

FIGURE 10. POWER REGULATOR WITH LOW TEMPERATURE COEFFICIENT

2-56

TEXAS ~
INSTRUMENTS
POST OFFICE BOX 655012 • DALLAS, TEXAS 75265

LT1009
2.5-V INTEGRATED REFERENCE CIRCUIT
TYPICAL APPLICATION DATA
5V

+

5V

-5 V

n

5 kll

10 kll
1%
OUT

9.76 kll
1%

•
...
II)

Q)
Q)

500 Il

.s::
en
ca
ca

...

C

-5 V

FIGURE 11. SWITCHABLE ± 1.25-V BIPOLAR REFERENCE
1 I'F

10 kll

1 kll

C>_-2.5V

LT1009

FIGURE 12. LOW-NOISE 2.5-V BUFFERED .REFERENCE

TEXAS •

INSTRUMENTS
POST OFFICE BOX 655012 • DALLAS, TEXAS 75265

2-57

o

...

Q)

Q)

en

::r
CD
CD

...en

2-58

LTC1044
SWITCHED-CAPACITOR VOLTAGE CONVERTER
D3193, JANUARY 1989

• Plug-In Compatible with the 7660 with
These Additional Features:
• Operation to 9 V Over Full Temperature
Range with No External Protection
Diodes
• Boost Pin for Higher Switching
Frequency
• 2 1/2 Times Lower Quiescent Power
• Efficient Voltage Doubler

LTC1044M ... JG PACKAGE
LTC1044C ... D. JG. OR P PACKAGE
(TOP VIEW)

B a a S T [ J 8 VDD
CAP+
2
7 asc
GND
3
6 LV
CAP4
5 Va

• No-Load Supply Current at
5 V ... 200 j.lA Max

L PACKAGE
(TOP VIEW)

fI
...

VDD

• Open-Circuit Voltage Conversion
Efficiency ..• 97% Min

en

• Power Conversion Efficiency ... 95% Min

CD
CD

.s:.

• Operating Supply Voltage Range .•. 1.5 V
to 9V

(J)

...

CAP-

• Commercial Device Operates from -40°C
to 85°C

CO
CO

C

description
The LTCl 044 is a mDnolithic CMOS switched-capacitor voltage converter manufactured using CMOS silicongate technology. The LTC1044 provides several voltage conversion functions; the input voltage can be
inverted lYo = -VI), doubled lYo = 2VI), divided lYo = VI/2), or multiplied lYo = ±nVI)·
Designed to be pin-for-pin and functionally compatible with the 7660, the LTC1044 offers significant new
design and performance advantages while still maintaining compatibility with existing 7660 designs.
The LTC1 044M is characterized for operation over the full military temperature range of -55°C to 125°C. The
LTC1044C is characterized for operation from -40°C to 85°C.

PRODUCTION DATA do.umonts.onloin information
cumnt I I of publication data. Products conform to
specifications per lhe terms of To.o. Instruments

:=~~;;ai:I~~i ~1::i~n l!~O:;:=::'S not

Copyright @ 1989. Texas Instruments Incorporated

TEXAS . "

INSTRUMENTS
POST OFFICE BOX 655012 • DALLAS, TEXAS 75265

2-59

LTC1044
SWITCHED-CAPACITOR VOLTAGE CONVERTER
absolute maximum ratings over operating free·air temperature ranget

•

Supply voltage, VDD . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 9.5 V
Input voltage range (pins 1,6, and 7, see Note 1) . . . . . . . . . . . . . . . . . . . . . " -0.3 V to VDD + 0.3 V
Input current, II (pin 6) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 IJA
Duration of output short circuit (VCC+ :;; 5.5 V) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. unlimited
Operating free-air temperature range: LTC1044M. . . . . . . . . . . . . . . . . . . . . . . . . . .. -55°C to 125°C
LTC1044C . . . . . . . . . . . . . . . . . . . . . . . . . . . . -40°C to 85°C
Storage temperature range ...... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. - 65°C to 150°C
Lead temperature 1,6 mm (1/16 inch) from case for 60 seconds: JG package. . . . . . . . . . . . . .. 300°C
Lead temperature 1,6 mm (1/16 inch) from case for 10 seconds: D or P package . . . . . . . . . . . . 260°C
L package . . . . . . . . . . . . . . .. 300°C

t Stresses beyond those listed under "absolute maximum ratings" may cause permanent damage to the device. These are stress ratings
only. and functional operation of the device at these or any other conditions beyond those indicated under "recommended operating
cond~ions" is not implied. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability.

C

....DlDl

recommended operating conditions

en

':f'
CD
CD

....en

LTC1044M
MIN
VOO
VI

Supply voltage (RL = 10 kil. see Note 1)
Input voltage (pins 1, 6, and 7, see Note 2)

TA

Operating free-air temperature

1.5
0.3
-55

MAX
9
VOO+0.3
125

LTC1044C
MIN
1.5
0.3
-40

MAX
9
VOO+0.3
85

UNIT
V
V
'C

NOTES: 1. The LTCI 044 operates with alkaline, mercury, or NiCad 9-V batteries, even when the initial battery voltage is slightly higher than 9 V.
2. Connecting any input terminal to voltages substantially greater than Voo or less than ground may cause destructive latch-up. It is
recommended that no inputs from sources operating from external supplies be applied prior to power-up of the LTC1044.

2-60

TEXAS ~

INSTRUMENTS
POST OFFICE BOX 655012 • DALLAS. TEXAS 75265

LTC1044
SWITCHED-CAPACITOR VOLTAGE CONVERTER
electrical characteristics at specified free-air temperature, Voo
Figure 1)
PARAMETER

ro

Output resistance

TEST CONDITIONS
10

= 20 rnA,

VOO
lose

Oscillator Irequency

'TJp

Power efficiency
Voltage conversion
efficiency
Oscillator sink or

nVO
lose
100

source current
Supply current

VOO

= 2 V,
= 5 V,

lose

= 5 kHz

= 3 rnA, lose = 1 kHz
Cos c = 1 pF, See Note 3

IL

VOO - 2 V, Cosc - 1 pF, See Note 3
RL - 5 kn, lose - 5 kHz

= 00
Vosc = 0 or VOO,
Vosc = 0 or VOO,
RL

RL RL

00,

= 00,

Pin 1 at 0 V

Pin 1 at VOO
Pins 1 and 7 no connection
Pins 1 and 7 VOO

=3V

TAt

= 5 V (unless otherwise noted, see
lTC1044M
MIN

TYP

lTC1044C

MAX MIN

TYP

MAX

25"C

100

100

Full range

150

130

Full range

400

325

Full range

5

5

1

1

95

98

95

98

25"C

97

99.9

97

99.9

3

25"C

%
%
3

20
60

20

200

60

20

n

kHz

25"C

Full range

UNIT

20

200

",A

lolA

Q)
Q)

J:

t Full range is -55"C to 125"C lor the LTC1044M and -40'C to 85'C lor the LTC1044C.
NOTE 3:

...en

losc is tested wrth Cos c at 100 pF to minimize the effects of test lixture capacitance loading. The l-pF frequency is correlated to this
1OO-pF test point and is intended to simulate the capacitance at pin 7 when the device is plugged into a test socket and no external
capacitor is ut;j:ed.

en

...
CI:I
CI:I

C
PARAMETER MEASUREMENT INFORMATION
Voo - 5 V

.-J--.--r-'--f-_ _ _ _ _ _ _ _ _-4I

~ts

I---~Y-O-<
EXTERNAL
OSCILLATOR

RL

llL

C2

Vo

rl0~F
FIGURE ,_ TEST CIRCUIT

TEXAS ~

INSTRUMENTS
POST OFFICE BOX 655012 • DALLAS, TEXAS 75265

2-61

LTC1044
SWITCHED-CAPACITOR VOLTAGE CONVERTER
TYPICAL CHARACTERISTICSt
SUPPLY CURRENT
vs
SUPPLY VOLTAGE

OUTPUT RESISTANCE
vs
SUPPLY VOLTAGE

400

RL -

1000

=

10 - 3 mA
25°CTA

00

360

'"f

~

320

~

280

~

/

240

U

':i

~ 200

C
C\)

..,.

C\)

0
z 120

....

....0

en

::::r

9

CD
CD

....

c

"

~

'iii
~ 100

~V

......V

o
o

2

3
4
5
6
7
8
VcC-Supply Voltage-V

9

10

10

o

2

FIGURE 2

360
320

c

·i.

240

a: 200
l160

o
I

--

--

VOO - 2 V. fosc l -

- ----

-

""-

VOO - 5 V. fosc = 5 kHz

1 kHz

.
l!!
.,
.

10

C1 = d2 1= 111

I

~~

u

c

300

'iii

a:

':i
So

200

B

\

\

1

-"

100

\
C1 1-

-25
0
25
50
75
100
TA-Free-Air Temperature- °C

125

o 0,1

....

\

\
....

~

~~

IC~ I~ I~I?O ~F
10
fos c -Oscillator Frequency-kHz

FIGURES

FIGURE 4

t Data at high and low temperatures are applicable only within the rated operating free-air temperature ranges of the two devices.

2-62

9

VOO - 5 V
10 = 10 mA
TA = 25°C

co 400

............

40

~55

3
4
5
6
7
8
VOO-Supply Voltage-V

C1 1 =1 d21

o"

120

B 80

"""- r--

.........

n~1~10
mr ,..~

500
C1 - C2 = 10,..F

u

..........
Cosc - 0

OUTPUT RESISTANCE
vs
OSCILLATOR FREQUENCY

400

I 280

Cosc = 100 pF

FIGURE 3

OUTPUT RESISTANCE
vs
FREE-AIR TEMPERATURE

..

"-

V
./

40

co

"-

,

I
~

)

80

(I)

co

/

160

I

Q

I

TEXAS

~

INSTRUMENTS
POST OFFICE BOX 655012 • DALLAS, TEXAS 75285

100

LTC1044
SWITCHED-CAPACITOR VOLTAGE CONVERTER
TYPICAL CHARACTERISTICSt
OSCILLATOR FREQUENCY
vs
EXTERNAL CAPACITOR
100

OSCILLATOR FREOUENCY
vs
SUPPLY VOLTAGE
100

.~~o =2:0~

N

J:

"'i
>".,c

N

...I

l~v6ol

~I

10

PIN 1 OPEN
Cosc - 0
TA = 25°C

J:

II
...

~ 10
c

.,.
CD

"

:J

C"

DP :~

....Ie

Ie

....

g

g
,lg

..

..

·u
o

I 0.1
~

Q)
Q)

/

,lg

·u
o

en

/

.c
en

...

I

CO

J"

.P

CO

C
0.1

0.01

1 pF

10 pF

100 pF

1 nF

10 nF

o

2

Cosc - External Capacitor
(Pin 7 to Ground)

3
4
5
6 7
8
VCC-Supply Voltage-V

9 10

FIGURE 7

FIGURE 6
POWER CONVERSION EFFICIENCY
vs
OSCILLATOR FREQUENCY

OSCILLATOR FREQUENCY
vs
FREE-AIR TEMPERATURE
15

N

:ii

100

Voo = 5 V
14 -PIN 1 OPEN
Cosc s 0

"""~
~ 11

.... 10

g
='" 9
.~

o

8

I
~ 7

.?

6

5
-55

>c

96

·u

94

-=wc

92

.,"

I

~12

c

Ie

98

I

13

C"

cF-

'"

~

~

c

1 I'F 10 = 1 mA..l

"" '"

88

~

86

0

.............

Q.

I

e:

............

-25
0
25
50
75
100
TA-Free-Air Temperature- °C

125

84

!

I

90

0

3:

1\'

1Ol'F

I
I

>

u

,,"

/'

0

.0;

VOO ~ 5 V
Cl - C2
,TA - 25°C

lOOI'F

I

1OOl'F

~ If

82
80
0.1

10 = 15 rnA

!

11/

I
1O I'F

VI II

I

1/

1 I'F

V I II

10
fos c -Oscillator Frequency-kHz

100

FIGURE 9

FIGURE 8

t Data at high and low temperatures are applicable only within the rated operating free-air temperature ranges of the two devices.

TEXAS . "

INSTRUMENTS
POST OFFICE BOX 655012 • DALLAS, TEXAS 75265

2-63

LTC1044
SWITCHED-CAPACITOR VOLTAGE CONVERTER
TYPICAL CHARACTERISTICS
POWER CONVERSION EFFICIENCY
and SUPPLY CURRENT
vs
OUTPUT CURRENT

POWER CONVERSION EFFICIENCY
and SUPPLY CURRENT
vs
OUTPUT CURRENT
100
~ 90

~80

E :170
C

...
I»

~

50

g 40

:::r

0
~

CD
CD

...

""- N
~p

g

I»

rn

I

.........

iii 60
.~

~

30

~ 20

!II

100

10

/

/

1

e:- 10

o/
o

/

/

/

/

1/

9

~ 90

8

~

V

70

ffi

60

:;

'f 50

50
>48:

\

'DO

"

til

31
0
- 29

VOO = 2 V
fose = 1 kHz
C1 - C2 = 10 I'F _
TA = 25°C

2
4
3
5
6
'O-Output Current-rnA

7

"

·8

6~

\

"'

80

'.!."

7 E

100

r-..

I:

I:

.........

>

g 40
0
~

30

0

~ 20

.,.

/

Q.

10

o/
o

o

/
10

/

/

'DO
VOO - 5 V
fose = 5 kHz
C1 - C2 = 1Ol'F
TA - 25°C I

OUTPUT VOLTAGE
vs
OUTPUT CURRENT

V~O 12 J

,
~,

0.5

'5

~'"

6

-1

./

-1.5

..... / '

-2
-2.5

o

2

'i'S"O~

/

-3

_.. ~o""
'"

~O~

o

I

Voo - 5 V _

"0

} . .~~o9.

0

o

>

'"
i

\.

.I

\

3

~
J!!

"

5"-0.5

4

>

>

g

,

5

_

fose = 1 kHz
TA = 25°C -

1

70

20
30
40
50
60
'O-Output Current-rnA

FIGURE 11

2.5

.
F

1o

o

OUTPUT VOLTAGE
vs
OUTPUT CURRENT

1.5

'.
\

FIGURE 10

2

,/
/\

/

0

.

90

~p

20 30 40 50 60 70 80 90 100
'O-Output Current-rnA

FIGURE 13

TEXAS ",

INSTRUMENTS
POST OFFICE BOX 655012 • DALLAS, TEXAS 75265

LTC1044
SWITCHED-CAPACITOR VOLTAGE CONVERTER
TYPICAL APPLICATION DATA

theory of operation
To understand the theory of operation olthe LTC 1044, a review of a basic switched-capacitor building block is
helpful. In Figure 14, when the switch is in the left position, capacitor C1 charges to voltage V1. The total
charge on C1 is q1 = C1 • V1. The switch then moves to the right, discharging C1 to voltage V2. After this
discharge time, the charge on C1 is q2 = C1 • V2. Note that charge has been transferred from the source, V1,
to the output, V2. The amount of charge transferred is calculated as follows:
Aq = q1 - q2 = C1(V1 - V2).
If the switch is cycled f times per second, the charge transfer per unit time (Le., current) is calculated as
follows:

I = f x Aq = f x C1 (V1 - V2).

II

Rewriting in terms of voltage and impedance equivalence,
V1 - V2
V1 - V2
1=---=-(1/fC1)
Req

ctI

where Req is defined as Req = 1/fC1. The equivalent circuit for the switched-capacitor network is shown in
Agu~1~

V,

I

I

;

C

-.I\IVI~.
V2
Req

rC2 ":" RL
NOTE: Req ~

FIGURE 14. SWITCHED-CAPACITOR
BUILDING BLOCK

,

fe,

FIGURE 15. SWITCHED-CAPACITOR
EQUIVALENT CIRCUIT

Examination of Figure 16 shows that the LTC1044 has the same switching action as the basic switchedcapacitor building block, with the addition of finite switch on-state resistance and output voltage ripple.
The simple theory, although not exact, helps illustrate how the device operates. For example, it explains how
the LTC 1044 behaves in Figure 9. The loss, and hence the efficiency, is determined by the output impedance.
As frequency is decreased, the output impedance is eventually dominated by the 1/fC1 term, and power
efficiency drops. Figure 9 shows this effect for various capacitor "alues.
Note also that power efficiency decreases as frequency increases. This is caused by internal switching losses
that occur because some finite charge is lost in each switching cycle. This charge loss per unit cycle, when
rnultiplied by the switching frequency, becornes a current loss. At high frequency, this loss becomes
significant, and the power efficiency starts to decrease.

TEXAS •

INSIRUMENTS
POST OFFICE BOX 655012 • DALLAS, TEXAS 75265

2-65

LTC1044
SWITCHED·CAPACITOR VOLTAGE CONVERTER
TYPICAL APPLICATION DATA

BOOST (11

•

OSC (71

C

I»
r+
I»

CLOSED WHEN
VDD 2: 3 V

en

FIGURE 16. LTC1044 SWITCHED-CAPACITOR VOLTAGE CONVERTER BLOCK DIAGRAM

::T

(1)

!.

LV (pin 6)

til

The internal logic of the LTC1 044 runs between VDD and LV (pin 6). For VDD ~ 3 V, an internal switch shorts
LV to GND (pin 3). The LV pin can be tied to ground or left floating. For VDD s; 3 V, the LV pin should be tied to
GND.

OSC (pin 7) and BOOST (pin 1)
The switching frequency can be raised, lowered, or driven from an external source. Figure 17 shows a
functional diagram of the oscillator circuit. By connecting the boost pin (pin 1) to VDD, the charge and
discharge current is increased, thereby increasing the frequency by a factor of approximately 7. Increasing
the frequency decreases output impedance and ripple for higher load currents. Loading pin 7 with more
capacitance lowers the frequency. USing the boost pin (pin 1) in conjunction with external capacitance on
pin 7 allows the user to select the frequency over a wide range.
Driving the LTC 1044 from an external frequency source can easily be achieved by driving pin 7 and leaving
the boost pin open, as shown in Figure 18. The output current from pin 7 is small, typically 0.5 fJA, so a logic
gate can drive this current. USing a CMOS logiC gate is preferable because it can operate over a wide supply
voltage range (3 V to 15 V) and has enough voltage swing to drive the internal Schmitt trigger shown in
Figure 17. For 5-V applications, a TIL logic gate can be used by simply adding an external pull-up resistor
(see Figure 18).

2-66

TEXAS . "

INSTRUMENlS
POST OFFICE BOX 855012 • DALLAS. TEXAS 75265

LTC1044
SWITCHED-CAPACITOR VOLTAGE CONVERTER
TYPICAL APPLICATION DATA

BOOST .;,.'1:..:..1--'--1~\

•
...
fI)

Q)
Q)

.c
o
as
as

osc
~14

...

pF

C

11

LV:..:..'6:..:..1____~~----~------J

FIGURE 17. OSCILLATOR
VOO(+1

Cl

FIGURE 18. EXTERNAL CLOCKING

external diode (Ox)
Previous circuits of this type have required a diode between Vo (pin 5) and the external capacitor C2 for
voltages above 6.5 V (5 V for military temperature range). The improvements in the LTC1044 circuit design
and Texas Instruments LinCMOS" silicon-gate process have eliminated the need for this diode. The
LTC1044 operates from 1.5 V to 9 V without the protection diode over all temperature ranges. The LTC 1044
will operate without any problems in existing LTC7660 designs that use the protection diode as long as the
maximum recommended supply voltage of 9 V is not exceeded.

LinCMOS is a trademark of Texas Instruments Incorporated.

TEXAS . "

INSTRUMENTS
POST OFFICE BOX 655012 • DALLAS, TeXAS 15265

2-67

LTC1044
SWITCHED-CAPACITOR VOLTAGE CONVERTER
TYPICAL APPLICATION DATA

capacitor selection
External capacitors C1 and C2 are not critical. They do not have to be high quality or have tight tolerance, nor
is matching required. Aluminum or tantalum electrolytics are excellent choices, with cost and size being the
only consideration.

negative voltage converter
Figure 19 shows a typical connection that provides a negative supply from an available positive supply. This
circuit operates over full temperature and power supply ranges without the need for external diodes. The LV
pin (pin 6) is shown grounded, but for VDD ;;;: 3 V, it may be floated, since LV is internally switched to ground
(pin 3) for VDD ;;;: 3 V.

o

The output voltage (pin 5) characteristics of the circuit are those of a nearly ideal voltage source in series with
an 80-0 resistor. The 80-0 output impedance is composed of two terms-the equivalent switched-capacitor
resistance (see Theory of Operation) and a term related to the on-state resistance of the MOS switches. At an
oscillator frequency of 10 kHz and C1 = 10 f.lF, the first term is:

!CI)
en
:::r
C'D
C'D

...en

R qe

-

1
(fosd2)

x

5 x 103 x 10 x 10-6

C1

= 200

Notice that the equation for Req is not a capacitive reactance equation (XC = l/roC) and does not contain a 21T
term. While the exact expression for output impedance is extremely complex, the dominant effect of the
capacitor is clearly shown in the typical curves of output impedance and power efficiency versus frequency.
For Cl = C2 = 10 f.lF, the output impedance goes from 600 at fosc = 10kHz to 200 0 at fosc = 1 kHz. As the
l/fC term becomes large compared to the switch on-state resistance term, the output resistance is
determined by l/fC only.
Voo 11.5 V TO 9 VI

10 pF

FIGURE 19. NEGATIVE VOLTAGE CONVERTER

voltage doubling
Figure 20 illustrates two methods of voltage doubling. In Figure 20(a), doubling is achieved by simply
rearranging the connection of the two external capacitors. When the input voltage is less than 3 V, an external
1-MO resistor is required to ensure that the oscillator starts; it is not required for higher input voltages.
In this application, the ground input (pin 3) is taken above VDD (pin 8) during power-on, making it prone to
latCh-Up. The latCh-Up, while not destructive, prevents the circuit from doubling. Resistor Rl is added to
eliminate this problem; in most cases, 200 0 is sufficient. It may be necessary in a particular application to
increase this value to guarantee start-up. The voltage drop across Rl is VRl = 2 x 10 x R2. If this voltage
exceeds two diode drops (1.4 V for silicon, 0.8 V for Schottky), the circuit in Figure 20(a) is recommended
because it will never have a start-up problem.

2-68

TEXAS ",
INSTRUMENTS
POST OFFICE BOX 655012 • DALLAS, TEXAS 75265

LTC1044
SWITCHED-CAPACITOR VOLTAGE CONVERTER
TYPICAL APPLICATION DATA
VI(1.5VT09VI
lN914

-

10

Rl
200 II

t--....------<.-...... 2VI

-l

Cl
10 pF

(3

V TO 18 VI

C2

":1~1I
10pF

1",

REQUIRED FOR
VI < 3 V

fI
...
II)

(a)

CI)
CI)

VI
(1.5 V TO 9 VI

.t:

en

...
CO

CO

C

Va

l

REQUIRED FOR
< 3V

I VDD

'--I~""-VO -

2(VI - 1)

1.
(b)

FIGURE 20. VOLTAGE DOUBLER

ultra-precision voltage divider
An ultra-precision voltage divider is shown in Figure 21. To achieve the 0.0002% accuracy indicated, the load
current should be kept below 100 nA. However, with a slight loss in accuracy, the load current can be
increased.
VDD (3 V TO 18 VI

Cl
10 pF
VDD

"""'2"

±0.002%

T~Tp~-\--1 ~
~

NOTE: TA

= MIN

REQUIRED FOR VDD

< 6V

to MAX. 10 :s 100 nA

FIGURE 21. ULTRA-PRECISION VOLTAGE DIVIDER

TEXAS

~

INSTRUMENTS
POST OFFICE BOX 655012 • DALLAS, TEXAS 76265

2-69

LTC1044
SWITCHED-CAPACITOR VOLTAGE CONVERTER
TYPICAL APPLICATION DATA

battery splitter
Obtaining positive and negative supplies from a single battery or single power supply is a common need in
many systems. Where current requirements are small, the circuit shown in Figure 22 is a simple solution. It
provides symmetrical positive and negative output voltages, both equal to one half the input voltage. The
output voltages are both referenced to pin 3 (output common). If the input voltage between pin 8 and pin 5 is
less than 6 V, pin 6 should also be connected to pin 3, as shown by the dashed line.

E

1--4I"'--+VB/2 14.5 VI

REQUIRED FOR VB

C

...
I»
I»

<

6 V

1-+-4I1---VB/2 1-4.5 VI

L----t--=======-4

en

:::r
(1)

...en

(1)

OUTPUT COMMON
NOTE: VB = 3 V to 18 V

FIGURE 22. BATIERY SPLITIER

paralleling for lower output resistance
Figures 23, 24, and 25 illustrate the flexibility of the LTC1044. Figure 23 shows two LTC1044s connected in
parallel to provide a lower effective output resistance. If, however, the output resistance is dominated by
1/fC1, increasing the size of C1 or increasing the frequency is more beneficial than the paralleling circuit
shown.
VDD

C1
10 pF

---..---....--f-+-~""~vo -

ISee Notel
NOTE: The exclusive NOR gate synchronizes both LTC1044s to minimize ripple.

FIGURE 23. PARALLELING FOR LOWER OUTPUT RESISTANCE

2-70

TEXAS . "

INSTRUMENTS
POST OFFice BOX 655012 • DALLAS. TeXAS 75265

- IVDDI

LTC1044
SWITCHED-CAPACITOR VOLTAGE CONVERTER
TYPICAL APPLICATION DATA
r::igures 24 and 25 "stack" two LTC1044s to provide even higher voltages. As shown schematically in
Igure 24, a negative voltage doubler or tripler can be achieved depending upon how pin 8 of the second
LTC1 044 is connected. Figure 25 illustrates a similar circuit that can be used to obtain positive tripling, or even
quadrupling [the doubler circuit appears in Figure 20(a)]. In both of these circuits, the available output current
is a function of the product of the individual power conversion efficiencies and the voltage step-up ratio.
I

vee
FOR Vo -

-3 vce _ _ _ _ FOR Va -

-2 Vee

II
I---~Vo

FIGURE 24. STACKING FOR HIGHER VOLTAGE
1N914

r---......-++vo

Vee (5 VI
1N914

FOR Vo - 3 V
(15 VI
_
L -_ _ _ _ _ _~~~_ _ _ _ _ _~~~I~

FOR Vo - 4 V

(20 VI

NOTE: Required for voo < 3 V

FIGURE 25. VOLTAGE TRIPLER/QUADRUPLER

TEXAS

.Jf

INSTRUMENTS
POST OFFICE BOX 655012 • DALLAS, TEXAS 75265

2-71

LTC1044
SWITCHED-CAPACITOR VOLTAGE CONVERTER
TYPICAL APPLICATION DATA

i - - - -.. 5V

100

~F

220 !l

•

OUTPUT
o V TO 3.5 V
o psi TO 350 psi

1.2·V REFERENCE TO
AID CONVERTER FOR
RATIOMETRIC OPERATION
11 mA MAXI

c
....
C\)

2 kll
GAIN
TRIM

®

C\)

(/)

46 kll
ISee Notel

~
(1)
(1)

lTl004
1.2 V

....UI

10 kll
301 kll
ZERO ~'"'IIII---t--~~-----'
TRIM
ISee Notel
I.::.J 350·11 PRESSURE
TRANSDUCER

LT1013

/AI

100 11 ISee Notel

o V ......®=::.E_+--___+_~

~ -1.2V

®

NOTE: 1% film resistor pressure transducer BLH/DHF-350 (Circled leiter is pin number)

FIGURE 26. SINGLE S-V STRAIN GAUGE BRIDGE SIGNAL CONDITIONER

~---~-~'----Vo

NOTE: Supply current 100 ~ 3~.

FIGURE 27. GENERATING CMOS LOGIC SUPPLY FROM 2 MERCURY BATTERIES

2-72

0.047

TEXAS •

INSTRUMENlS
POST OFFICE BOX 655012 • DALLAS, TEXAS 75265

~F

LTC1044
SWITCHED-CAPACITOR VOLTAGE CONVERTER
TYPICAL APPLICATION DATA
3V

HH..-...--+-----I~5 V OUTPUT

4.8 Mil

II
...
I/)

EVEREADY EXP-30

CI)
CI)

-=-

.s:.

en

...
CIS
CIS

o

1 k!l
330 k!l

lN914

FIGURE 28. REGULATED OUTPUT 3-V TO 5-V CONVERTER

200 kll
8.2 k!l

,..--_e_e-OUTPUT

200 kll

39 kll

0.1

tvl ;;:

I-Vo I + 0.5 V

NOTE: Load regulation ±0.02%. 0 to 15 rnA.

FIGURE 29: LOW-OUTPUT-IMPEDANCE VOLTAGE CONVERTER

TEXAS

~

INSTRUMENTS
POST OFFICE BOX 655012 • DALLAS, TEXAS 75265

2-73

LTC1044
SWITCHED-CAPACITOR VOLTAGE CONVERTER
TYPICAL APPLICATION DATA
2N2219

) r.....- , Vo - 5 V
1N914
~+-+-...,12V

120
kll

100 Il
100 kll
1 Mil
4 EVEREADY - 6 V
E-91 CELLS-

SHORT CIRCUIT
PROTECTION

l------

8

LOAD

FEEDBACK AMP
5

4
LT1004
1.2 V

1N914
1.2 kll

0.01 Il
V dropout at 1 rnA - 1 rnV
Vdropout at 10 rnA - 15 rnV
Vdropout at 100 rnA - 95 rnA

FIGURE 30_ LOW-DROPOUT 5-V REGULATOR

2-74

TEXAS •

INSTRUMENTS
POST OFFICE BOX 655012 • DALLAS. TEXAS 75265

30 kll

MC3423
OVERVOLTAGE-SENSING CIRCUIT
02439. APRIL 1978-REVISEO MARCH 1988

•

Separate Outputs for "Crowbar" and Logic
Circuitry

•

Programmable Time Delay to Eliminate
Noise Triggering

•

TTL-Level Activation Isolated from VoltageSensing Inputs

•

2.S-Volt Internal Voltage Reference with
Temperature Coefficient Typically O.08%/OC

D. JG. OR P PACKAGE
ITOPVIEW)
V C C D B OUT
SENSE 1 2
7
VEE
SENSE 2 3
6
IND OUT
CURR SOURCE 4
5
REMOTE ACTIVATE

description
The MC3423 overvoltage-sensing circuit is designed to protect sensitive electronic circuitry by monitoring
the supply rail and triggering an external "crowbar" SCR in the event of a voltage transient or loss of
regulation. The protective mechanism may be activated by an overvoltage condition at the Sense 2 input
or by application of a TTL high level to the Remote Activate terminal. Separate outputs are available to
trigger the crowbar circuit and to provide a logic pulse to indicator or power supply control circuitry. The
Sense 2 input provides a direct control of the output circuitry. The Sense 1 input controls an internal current
source that may be utilized to implement a delayed trigger by connecting its output to an external capacitor
and the Sense 2 input. This protects against false triggering due to noise at the Sense 1 input.

...
III

CI)
CI)

.c

(J)

ca

10

Q

The MC3423 is characterized for operation from OOC to 70°C.

functional block diagram
VCC
(1)

(4) CURRENT

~------------------------------------~-SOURCE

SENSE1~~--~---.~-a

SENSE2~13~)---+----~------------+------t
IBI

~--------e-~OUTPUT

(7)

VEE

PRODUCTION DATA documants contain information
currant 8S of publication data. Products conform to
specifications per tb. terms of Texas Instruments

:':~:~~8rnr:I~7i ~!~::i:; :.r:=::9t:~~1 not

151
REMOTE
ACTIVATE

(6)

INDICATOR
OUTPUT

Copyright @ 1983, Texas Instruments Incorporated

TEXAS . "

INSTRUMENTS
POST OFFICE BOX 655012 • DALLAS, TEXAS 75265

2-75

MC3423
OVERVOLTAGE·SENSING CIRCUIT
absolute maximum ratings
SupplV voltage, VCC (see Note 1) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 40 V
Sense 1 voltage ........................................................... 6.5 V
Sense 2 voltage ........................................................... 6.5 V
Remote activate input voltage. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 7 V
Output current, 10 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 300 mA
Continuous total dissipation: ................................ See Dissipation Rating Table
Operating free-air temperature range. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. ooC to 70°C
Storage temperature range ......................................... - 65°C to 150°C
Lead temperature 1,6 mm (1116 inch) from case for 10 seconds: D or P package. . . . . . . .. 260°C
Lead temperature 1,6 mm (1116 inch) from case for 60 seconds: JG package ........... 300°C
NOTE 1: Voltage values are measured with respect to the VEE terminal.

c

DISSIPATION RATING TABLE

....

D)

D)

PACKAGE

en

':f'
CD
CD

....111

TA s 25·C

DERATING FACTOR

POWER RATING

TA - 70·C
POWER RATING

D

725 mW

ABOVE TA - 2S·C
5.8 mW/oC

JG

825 mW

6.6 mW/oC

528 mW

P

1000 mW

B.O mW/oC

640 mW

464 mW

recommended operating conditions
MIN

MAX

4.5

40

V

0.5

V
V

Supply voltage, VCC
High-Jevel input voltage, remote activate input

2

Low-level input voltage, remote activate input

UNIT

electrical characteristics over operating free-air temperature range, Vee'" 5 V to 36 V (unless otherwise
notedl
PARAMETER

TEST CONDITIONS
Remote Activate at 2 V,

Output voltage

10 = 100mA
Remote Activate at 2 V,

Indicator low-level output voltage

10

Threshold voltage of either sense input

TA

= 1.6 mA
= 25°C

MIN

MAX

2.45

0.1

0.4

2.6

2.75

V
%/·C

0.3
40
-lBO

mA

5
-120
6

10

mA

0.06

Source current (pin 41

Sense 1 at 3 V, Pin 4 at 1.3 V

High-level input current, Remote Activate input

VCC

low-level input current, Remote Activate input
Supply current

VI
VCC
Outputs open

Propagation delay time, Remote Activate input to output

TA

Output current rate of rise

TA - 25°C

= 5 V,
= 5 V,

VI

=2 V
= 0.8 V

= 25°C

TEXAS . "

INSlRUMENTS
POST OFFICE BOX 655012 • DALLAS. TEXAS 75265

0.1

UNIT
V

VCC-2.2 VCC-l.8

Temperature coefficient of input threshold voltage

2-76

TVP

0.22

0.5
400

V

~A

~
~

mA/~

SERIES MC79LOO
NEGATIVE-VOLTAGE REGULATORS
02565. OCTOBER 1982-REVISEO APRIL 1988

•

3-Terminal Regulators

•

Output Current Up to 100 mA

•

No External Components Required

•

Internal Thermal Overload Protection

•

Internal Short Circuit Current limiting

•

Direct Replacement for Motorola
MC79LOO Series

•

Available in 5% or 10% Selections

NOMINAL

5%

10%

OUTPUT

OUTPUT VOLTAGE

OUTPUT VOLTAGE

VOLTAGE

TOLERANCE

TOLERANCE

-5 V

MC79L05AC

MC79L05C

-12 V

MC79L12AC

MC79L12C

-15 V

MC79L15AC

MC79L 15C

DB
D PACKAGE
(TOP VIEW)

description
This series of fixed-voltage monolithic
integrated-circuit voltage regulators is designed
for a wide range of applications. These include
on-card regulation for elimination of noise and
distribution problems associated with singlepoint regulation. In addition, they can be used
to control series; pass elements to make highcurrent voltage-regulator circuits. One of these
regulators can deliver up to 100 mA of output
current. The internal current-limiting and
thermal-shutdown features make them
essentially immune to overload. When used as
a replacement for a Zener-diode and resistor
combination, these devices can provide an
effective improvement in output impedance of
two orders of magnitude and lower bias current.

OUTPUT
INPUT
INPUT
NC

2
3
4

7
6
5

NC
)NPUT
INPUT
COMMON

fI
...
til

Q)
Q)

LP SILECT PACKAGE

J:

(TOP VIEW)

(J)
OUTPUT

...

INPUT

C

ctI
ctI

COMMON

NC-No internal connection

schematic
r---~--~---e--~~--'-----~~--------------------------~---GND

OUTPUT

~--~--------------------~~-------------e----~~--~~----e---INPUT

PRODUCTION DATA docomenb contain information
current as of publication data. Products conform to
specifications par the tarms of Texas Instruments

::=:~~i~ai~:1~1i ~:~~~i:r 1!r:::~~~~s not

Copyright © 1982, Texas Instruments Incorporated

TEXAS . "

INSTRUMENTS
POST OFFICE BOX 655012 • DALLAS, TEXAS 75265

2-77

SERIES MC79LDD
NEGATIVE-VOLTAGE REGULATORS

absolute maximum ratings over

oper~ting

free-air temperature range (unless otherwise notedl

I =~~:~~: I

MC79L05

Continuous total dissipation

I

-35

UNIT
V

See Dissipation Rating Tables 1 and 2

o to

Operating free-air, case, or virtual junction temperature range
Storage temperature range

I

150

-65 to 150

Lead temperature 1,6 mm (1/16 inchl from case for 10 seconds

•

I

-30

Input voltage

260

Ot0150

I

I -65 to 150 I
I 260
I

°C
°C
°C

DISSIPATION RATING TABLE 1-FREE AIR TEMPERATURE
PACKAGE

TA

s

25'C

DERATING

DERATE
ABOVE TA

TA - 70'C
POWER RATING

POWER RATING

FACTOR

825 mW

6.6 mW/oC

528 mW

775 mW

6.2 mW/oC

496 mW

D
LPt

tThe LP package dissipation rating is based on thermal resistance measured in still air
with the device mounted in an Augat socket. The bottom of the package was 10 mm
10.375 in.) above the socket.
DISSIPATION RATING TABLE 2-CASE TEMPERATURE
PACKAGE

TC

s

25°C

POWER RATING

DERATING

DERATE

FACTOR

ABOVE TC

D

1600 mW

29.0 mW/oC

LP

1600 mW

28.6 mW/oC

TC - 125°C
POWER RATING

725 mW
715 mW

recommended operating conditions

I MC79L05
I MC79L12
I MC79L15

Input voltage, VI

MIN

MAX

-7

-20

-14.5

-27

-17.5

-30

Output current, 10
0

Operating virtual junction temperature, T J

2-78

TEXAS ",
INSTRUMENTS
POST OFFICE BOX 656012 • DALLAS, TeXAS 75265

UNIT
V

100

mA

125

°c

SERIES MC79LOO
NEGATIVE·VOLTAGE REGULATORS
MC79L05 electrical characteristics at specified virtual junction temperature, VI - - 10 V, 10 ,. 40 mA
(unless otherwise noted)
PARAMETER

Output voltage

*

Input regulation

Ripple rejection

25°C

MC79L05C
TYP
MAX
-4.6
-5
-5.4

MIN
-4.8

to 125°C

-4.5

-5.5

-4.75

-5.25

OOCto 125°C

-4.5

-5.5

-4.75

-5.25

TEST CONOITIONSt

VI = -7 V to -20 V,
10 = 1 mA to 40 mA
VI = -10V,
10 = 1 mA to 70 mA
-7 Vto -20V

MIN

oDe

VI -

25°C

VI = -8 V to -20 V
VI = -8Vto -18V,

25°C

f=120Hz

Output regulation

10=1mAt0100mA

40

Output noise voltage

f = 10 Hz to 100 kHz

25°C

40

Dropout voltage

10 = 40 mA

25°C

1.7

Bias current change

VI = -8 V to -20 V
10 = 1 mA to 40 mA

MAX
-5.2

150

150

100
41

49
60

30

30

6

5.5
1.5

5.5
1.5

0.2

0.1

Output voltage

*

Input regulation

Ripple rejection
Output regulation

VI = -14.5 V to -27 V,
10 = 1 mA to 40 mA
VI = -19V,
10 = 1 mA to 70 mA
VI = -14.5 V to -27 V
VI = -16Vto -27V
VI = -15Vto-25V,
f=120Hz
10 = 1 mA to 100 mA

Output noise voltage

10 = 1 mA to 40 mA
f = 10 Hz to 100 kHz

Dropout voltage

10 = 40 mA

VI = -16 Vto -27 V
10 = 1 mA to 40 mA

MC79L12AC

25°C
OOC to 125°C

-10.8

-13.2

-11.4

-12.6

-10.8

-13.2

-11.4

-12.6

OOC to 125°C

TYP
-12

25°C
25°C

36

MIN
-11.5

TYP
-12

250

200

200
37

42

100

50
1.7

6.5

CI)
CI)

J:

(J)

...caca

mA

C

mA

UNIT

V

mV

mV
~V

80

80
1.7

II)

dB

100

50

OOCto 125°C

MAX
-12.5

250

42

25°C
25°C
25°C

MAX
-12.9

...

mV

40mA

MIN
-11.1

25°C
125°C

Bias current
Bias current change

MC79L12C

TEST CONOITIONSt

mV

V

6

MC79L 12 electrical characteristics at specified virtual junction temperature, VI = - 19 V, 10
(unless otherwise noted)
PARAMETER

V

~V

1.7

O°Cto 125°C

UNIT

dB

60
40

25°C
125°C

Bias current

TYP
-5

200

49

25°C

10 - 1 mA to 40 mA

MC79L05AC

V
6.5

6

6

1.5
0.2

1.5
0.1

mA
mA

t All characteristics are measured with a O.33-JtF capacitor across the input and a O.1-#LF capacitor across the output. Pulse testing techniques
are used to maintain the junction temperature as close to the ambient temperature as possible. Thermal effects must be taken into account
separately.
:t:This specification applies only for dc power dissipation permitted by absolute maximum ratings.

TEXAS . "

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POST OFFiCe BOX 655012 • DALLAS. TEXAS 75265

2-79

SERIES MC79LOO
NEGATlVE·VOLTAGE REGULATORS

MC79L 15 electrical characteristics at specified virtual junction temperature, VI (unless otherwise noted)
PARAMETER

MC79L15C

TEST CONDITIDNSt

25°C
Output voltage 01=

•

Input regulation
Ripple rejection

C

Output regulation

m

Output noise voltage

(J)

Dropout voltage

CD
CD

:::T

Bias current

UI

Bias current change

m
r+

r+

VI = -17.5Vto -30 V,
oOeto 125°e
10 = 1 mAto 40 mA
VI = -23 V,
ooe to 125°e
10 = 1 mA to 70 mA
VI = -17.5 V to -30 V
25°e
VI=-20Vto-30V
VI = -18.5 V to -28.5 V,
25°e
f=120Hz
10 - 1 mA to 100 mA
25°e
10 = 1 mAto 40 mA
f = 10 Hz to 100 kHz
25°e
25°e
10 = 40 mA
25°e
125°e
VI = -20 V to -30 V
ooe to 125°e
10 = 1 mA to 40 mA

- 23 V, 10 - 40 mA
MC79L15AC

MIN

TYP

MAX

MIN

TYP

-13.8

-15

-16.2

-14.4

-15

MAX

-15.6

-13.5

-16.5 -14.25

-15.75

-13.5

-16.5 -14.25

-15.75

300
250
33

39

300
250
34

39

150
75
90
1.7

V

mV
dB

150
75
90
1.7

6.5
6
1.5
0.2

UNIT

mV
/LV
V

6.5
6
1.5
0.1

mA
mA

t All characteristics are measured with a O.33-I'F capacitor across the input and a O.l-I'F capacitor across the output. Pulse testing techniques
are used to maintain the junction temperature as close to the ambient temperature as possible. Thermal effects must be taken into account
separately.
tThis specification applies only for de power dissipation permitted by absolute maximum ratings.

2-80

TEXAS ...,
INSTRUMENTS
POST OFFICE BOX 655012 • DALLAS. TEXAS 75265

MC34060
PULSE-WIDTH-MODULATION CONTROL CIRCUIT
D2714. MARCH 1983-REVISED FEBRUARY 1988

D OR N PACKAGE

•

Complete PWM Power Control Circuitry

•

Uncommitted Output for 200-mA Sink or
Source Current

(TOPVIEWI
ERROR {NONINV INPUT 1
NONINV INPUT}ERROR
AMP 1
INV INPUT
INV INPUT
AMP 2
FEEDBACK 3
REF OUT
DEAD·TIME CONTROL
NC
CT
VCC
RT 6
C
GND""1..7_ _;.r-

•

Variable Dead-Time Provides Control Over
Total Range

•

Internal Regulator Provides a Stable 5-V
Reference Supply

•

Circuit Architecture Provides Easy
Synchronization

•

Direct Replacement for Motorola MC34060

NC - No internal connections

II
...
II)

description

Q)
Q)

The MC34060 incorporates on a single monolithic chip all the functions required in the construction of
a pulse-width-modulation control circuit. Designed primarily for power supply control, the device contains
an on-chip 5-V regulator, two error amplifiers, an adjustable oscillator, and a dead-time control comparator.
The uncommitted output transistor provides either common-emitter or emitter-follower output capability.
The internal amplifiers exhibit a common-mode voltage range from -0.3 V to VCC - 2 V. The dead-time
control comparator has a fixed offset that provides approximately 5% dead time unless externally altered.
The on-chip oscillator may be bypassed by terminating RT (pin 6) to the reference output and providing
a sawtooth input to CT (pin 5), or it may be used to drive the common MC34060 circuitry and provide
a sawtooth input for associated control circuitry in multiple rail power supplies.

.c

en

...
CO
CO

C

The MC34060 is characterized for operation from ooC to 70°C.

functional block diagram
(101

Vcc"----l

REFERENCE

1-_______________{_1~21

REFERENCE

REGULATOR

RT~(6~1____~------l

CT~(5~1~~1-______J
DEAD·TIME CONTROL .:.(4...;1.:.--+_ _ _ _-It-_ _-t_ _-i

NON INVERTING INPUT

E

(11

..:....;---~....

....~t---1

(21
>-I~
INVERTING INPUT " ' - ' - - - - I ; ; ,
NON INVERTING INPUT .;.(1_4"'1_ _-C.....
(131
INVERTING INPUT "-"---i7'

>-__M---.

FEEDBACK "'{3:..:1_ _ _ _ _ _ _---'
All voltage and current values shown are nominal.

PRODUCTION DATA documenls contain information
current as of publication data. Products conform to
specifications p.r the terms of Texas Instruments
::'~:~~i~I{::1~1i ~:~~~i:r :I~O::~:::~::S~S not

Copyright © , 983, Texas Instruments Incorporated

TEXAS . "

INSTRUMENTS
POST OFFICE BOX 655012 • DALLAS, TEXAS 75265

2-81

MC34060
PULSE-WIDTH-MODULATION CONTROL CIRCUIT
absolute maximum ratings over operating temperature range (unless otherwise noted)
UNIT
Supply voltage, Vcc (see Note 11
Amplifier input voltages
Collector output voltage
Collector output current

Storage temperature range

o to 70

I

°C

-65 to 150

I
I

°C

Lead temperature 1.6 mm (1/16 inchl from case for 10 seconds: D or N package

260

°C

NOTE 1: All voltage values except differential voltages are with respect to the network ground terminal.

C

DISSIPATION RATING TABLE

I»
r+
I»

PACKAGE

tn

-:r

CD
CD

en

V
V

Table

Operating freeMair temperature range

r+

V

VCC+0.3
42

mA
250
See Dissipation Rating

Continuous total dissipation

E

42

TA:S 25°C
POWER RATING

DERATING

DERATE
ABOVE TA
31°C
41°C

D

900 mW

FACTOR
7.6 mW/oC

N

1000mW

9.2 mW/oC

TA - 70°C
POWER RATING
608 mW
736 mW

recommended operating conditions
Supply voltage, VCC
Amplifier input VOltages, VI
Collector output voltage, Va
Collector output current (each transistor)

MIN

MAX

7

40

V

-0.3 VCC-2
40
200

V
V
mA

10

mA

0.3

mA

Reference output current
Current into feedback terminal

Timing capacitor, CT
Timing resistor, RT
Oscillator frequency

2-82

0.47

10000

nF

1.8
1

500

kll

200
70

kHz

0

Operating free-air temperature, T A

TEXAS . "

INSTRUMENTS
POST OFFICE BOX 856012 • DALLAS. TEXAS 75265

UNIT

°c

MC34060
PULSE-WIDTH-MODULATION CONTROL CIRCUIT
electrical characteristics over recommended operating free-air temperature range.
f = 25 kHz (unless otherwise noted)

Vee -

15

V.

reference section
TEST CONDITIONSt

PARAMETER
~

Output voltage (Vrefl

10

Input regulation

VCC

Output regulation

110

Output voltage change

with temperature

MIN

TYP*

MAX

4.75

5

5.25

7 V to 40 V, TA ~ 25°C

2

25

mV

TA ~ 25°C

1

15

mV

0.2%

2.6%

1 mA
~

~

1 to 10 mA,

.:IoTA

~

V

- 0 T

Short-circuit outDut current §

MIN to MAX
- 25°C

UNIT
V

mA

35

oscillator section
TEST CONDITIONSt

PARAMETER
Frequency

CT ~ 0.001 ~F,

Standard deviation of frequency1

CT

~

~

25

RT ~ 47 kll

3%

7 V to 40 V, TA ~ 25°C

0.1%

~F,

Frequency change with voltage

VCC

Frequency change with

CT ~ 0.001 ~F,

temperature

.:IoTA

~

~

TYP*

47 kll

0.001

RT

MIN

RT

~

MAX

UNIT
kHz

(I)

Q)
Q)

.c
CI)

47 kll,

....asas

±2%

MIN to MAX

C

dead-time control-section (see Figure 1)
PARAMETER

TEST CONDITIONS

Input bias current (pin 4)

VI - 0 to 5.25 V

Maximum duty cycle

VI (pin 41 ~ 0

Input threshold voltage (pin 41

fI
....

I CT
I CT

~ 0.1 ~F,

MIN
RT

~

12 kll

~ 0.001 ~F, RT

~

47 kll

90%

Zero duty cycle
Maximum duty cycle

TYP*
-2

MAX

UNIT

-10

~A

96%

100%

92%

100%

3

3.3

0

V

error-amplifier sections
PARAMETER

TEST CONDITIONS
Va (pin 31 ~ 2.5 V

TYP*
2

MAX

Input offset voltage

MIN

Input offset current

Va (pin 31 ~ 2.5 V

25

250

nA

Input bias current

Va (pin 31 ~ 2.5 V

0.2

1

~A

Common-mode input voltage range

VCC ~ 7 V to 40 V

10

UNIT
mV

-0.3
to

V

VCC-2
~

Open-loop voltage amplification

.:IoVO

Unity gain bandwidth

Va

~

0.5 V to 3.5 V, RL

Phase margin at unity gain

Va

~

0.5 V to 3.5 V,

Common-mode rejection ratio

Output sink Current (pin 31

VCC ~ 40 V
VID ~ -15mVto -5V,

Output source current (pin 3)

VID

~

3 V,

RL - 2 kll, Va

15 mV to 5 V,

~

~

0.5 V to 3.5 V

70

2 kll
RL

~

2 kO
65

V(pin 31

~

0.7 V

0.3

V(pin 31

~

3.5 V

-2

95

dB

800

kHz

65°
80

dB

0.7

mA
mA

t For conditions shown as MIN or MAX. use the appropriate value specified under recommended operating conditions.
typical values except for "change with temperature" characteristics are at T A == 25°C.
§ Duration of the short~circuit should not exceed one second.
E (xn - X)2
, Standard deviation is a measure of the statistical distribution about the mean as derived from the formula u
n == 1
N - ,

"N..------

:t: All

~

TEXAS •

INSTRUMENTS
POST OFFICE BOX 655012 • DALLAS, TEXAS 75265

2-83

MC34060
PULSE-WIDTH-MODULATION CONTROL CIRCUIT
electrical characteristics over recommended operating free-air temperature range.
f ... 25 kHz (unless otherwise noted) (continued)

Vee -

15

V.

output section
PARAMETER
Collector

off~state

TEST CONDITIONS

current

VeE = 40 V,

Emitter off-state current

Collector-emitter

MAX

UNIT

2

100

p.A
p.A

-100

I Common-emitter

VE = 0,

Ie = 200 mA

1.1

1.3

Ve -

IE = -200 mA

1.5

2.5

Typt

MAX

4

4.5

15 V,

V

pwm comparator section (see Figure 11
PARAMETER
Input threshold voltage Ipin 3)

C

I»
r+
I»

Typt

Vee = Ve = 40 V, VE = 0

saturation voltage I Emitter follower

E

MIN

Vee = 40 V

Input sink current (pin 3)

I

I

TEST eONDITIONS

I

I

MIN

I

Zero duty cycle

I

V(pin 3) = 0.7 V

0.3

0.7

MIN

I
I

1

UNIT
V
mA

total device

en

PARAMETER

:r
CD
CD

Pin 6 at Vref,
All other inputs and outputs open

Average supply current

V(pin 4) = 2 V,

r+

en

Typt

MAX

Vee=15V

6

10

Vee = 40 V

9

15

TEST CONDITIONS

Standby supply current

L
I

RT = 47 kll,

eT = 0.001 ~F,

7.5

See Figure 1

UNIT
mA
mA

switching characteristics. T A - 25°C
PARAMETER
Output voltage rise time
Output voltage fall time
Output voltage rise time
Output voltage fall time

TEST CONDITIONS

Common-emitter configuration, See Figure 3
Emitter-follower configuration, See Figure 4

t All typical values are at T A = 25 ·e.

2-84

TEXAS

~

INSTRUMENTS
POST OFFICE BOX 655012 • DALLAS, TeXAS 75265

MIN

Typt

MAX

UNIT

100

200

ns

25

100

ns

100

200

ns

40

100

ns

I
I

I

MC34060
PULSE·WIDTH·MODULATION CONTROL CIRCUIT
PARAMETER MEASUREMENT INFORMATION

=

VCC

15V

150 Il
2 W

(10)
VCC
(4)

TEST {
INPUTS

C

OUTPUT 1

(B)

E

(3)
RT

(9)

DEAD·TIME

~

FEEDBACK

(6)

RT

1

\I

(5)

CT

~~

"}

(2)

(-)

(14)

~

(+)

(13)

ERRDR

(-)

REF
OUT

50 kll

~

GND

J:7)
TEST CIRCUIT
CAPACITOR CT " -

FEEDBACK

/141z1zotZ1Z1
r

~l6l4ri '

DEAD-TIME CONTROL .... I

I

I
I
I

I
I
I

I
I
I

I

I

I
I
I

I
I
I

I
I
I

I

I

I
I
I

I
I
I

EMITTER
OUTPUT

TIMING WAVEFORMS

FIGURE 1. DEAD·TIME AND FEEDBACK CONTROL
ERROR
AMPLIFIER
FEEDBACK
TERMINAL

ERROR
AMPLIFIER

FIGURE 2. ERROR·AMPLIFIER CHARACTERISTICS

TEXAS ."

INsrRUMENlS
POST OFFICE BOX 655012 • DALLAS, TEXAS 75265

2-85

MC34060
PULSE-WIDTH-MODULATION CONTROL CIRCUIT
PARAMETER MEASUREMENT INFORMATION
15V

IiOUTPUTCiRcUiT)~

...---(>-........-OUTPUT

I

•

I
I
I
-----(>--.
I1.. _____ .JI

en

:::r

CD
CD

r+

en

OUTPUT VOLTAGE WAVEFORM

TEST CIRCUIT

FIGURE 3. COMMON-EMITTER CONFIGURATION

C

I»
r+
I»

CL - 15 pF
(includes probe and
jig capacitance)

liOiiTpUr CiRCUIT) 1

15V

I

I
I
I
.......~)-<.-....-OUTPUT
IL _____ JI
68 O.
2W

CL- 15pF
(includes probe and
jig capacitance)

OUTPUT VOLTAGE WAVEFORM

TEST CIRCUIT

FIGURE 4. EMITTER-FOLLOWER CONFIGURATION

2-86

TEXAS ~

INSTRUMENTS
POST OFFICE BOX 655012 • DALLAS, TEXAS 75265

MC34060
PULSE·WIDTH·MODULATION CONTROL CIRCUIT
TYPICAL CHARACTERISTICS
OSCILLATOR FREQUENCY and
FREQUENCY VARIATIONt vs
TIMING RESISTANCE

AMPLIFIER VOLTAGE AMPLIFICATION
vs
FREQUENCY

100 k

100
Vee - 15 V
25°e
TA

40 k

--

2%

~

~ 10 k

I
>- 4 k

"~
"~

...

I

:l!!
'uII>

"

Ol~
'00,

'1,

1 k

to 80

bo 70

.~ 60

1k- - -

"'~

"l'

.. ,1/

100

~

50

~

40

E

1%t

.:If

r--"

'to

"'~

0%-t- .....'! 0,
"'~

I

g 400

0

I

1%

90

en

>

40

II

'\.

"'\.

~ 30

"'~

"- f\.

Vee D 15 V
.:lVo - 3 V
TA - 25°e

~

'\.

20

"-

10

t-...

10
1 k

4 k 10 k

40 k 100 k
RT- Timing Resistance-!1

400 k 1 M

o
1

10

FIGURE 5

100
1k
10 k
f - Frequencv - Hz

'\.

100 k

1 M

FIGURE 6

tFrequency variation (.6.f) is the change in oscillator frequency that occurs over the full temperature range.

TEXAS ."

INSTRUMENTS
POST OFFICE BOX 655012 • DALLAS, TEXAS 75265

2·87

E

C

III
r+
III
(J)

'::f'
CD
CD
r+

IJI

2-88

SG2524, SG3524
REGULATING PULSE-WIDTH MODULATORS
02294. APRIL 1977-REVISEO OCTOBER 19BB

•

Complete PWM Power Control Circuitry

•

Uncommitted Outputs for Single-Ended or
Push-Pull Applications

•

Low Standby Current ... 8 mA Typ

•

Interchangeable with Silicon General
SG2524 and SG3524

J OR N PACKAGE
(TOP

ININ+
OSC OUT
CURR LlM+
CURR LlMRT
CT
GND

description

VIEWI
REF OUT
VCC
EMIT 2
COL 2
COL 1
EMIT 1
SHUTDOWN

II
...

'-f.:::_....::J1-' CaMP
The SG2524 and SG3524 incorporate on single
monolithic chips all the functions required in the
construction of a regulating power supply,
inverter, or switching regulator. They can also be used as the control element for high-power-output
applications. The SG2524 and SG3524 were designed for switching regulators of either polarity,
transformer-coupled dc-to-dc converters, transformerless voltage doublers, and polarity converter
applications employing fixed-frequency, pulse-width-modulation techniques. The complementary output
allows either single-ended or push-pull application. Each device includes an on-chip regulator, error amplifier,
programmable oscillator, pulse-steering flip-flop, two uncommitted pass transistors, a high-gain comparator,
and current-limiting and shut-down circuitry.

en
Q)
Q)

..c:
en

...
CO
CO

C

The SG2524 is characterized for operation from - 25 °e to 85°e, and the SG3524 is characterized for
operation from ooe to 70 oe.

functional block diagram
~_ _ _~~-----------~ll~61 RE'OUT

COL 2
1141 EMIT 2

1-____...---'-.:.:...___.....~--_---13-1 OSC OUT
INVERTING
INPUT IN-

COMPARATOR

NONINVERTING
INPUT IN+
COMP~----""

ERROR
AMPLIFIER

CURR LIM +
CURR LIM -

SHUTDOWN ..:.11;,:0",,1"""......H
1 kG

10 kO
GND ..:.18-'1_ _....~....

Resistor values shown are nominal.

PRODUCTION DATA doc.monls contain information
current as of publication date. Products conform ta
specifications par the tarms of Texas Instruments

=-:!:~~ir;arn~,:r~ ~:::~i:; :.r:=::~:a~ not

TEXAS ~.
INSTRUMENTS
POST OFFICE BOX 655012 • DALLAS, TEXAS 75265

Copyright © 1982, Texas Instruments Incorporated

2-89

SG2524, SG3524
REGULATING PULSE-WIDTH MODULATORS
absolute maximum ratings over operating free-air temperature range (unless otherwise noted)
Supply voltage, VCC (see Notes 1 ,md 2) .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 40 V
Collector output current . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 100 mA
Reference output current . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 50 mA
Current through CT terminal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. - 5 mA
Continuous total dissipation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. See Dissipation Rating Table
Operating free-air temperature range: SG2524 ........................... - 25 °e to 85°C
SG3524 .............................. ooe to 70°C
Storage temperature range ......................................... - 65 °e to 150°C
NOTES: 1. All voltage values are with respect to network ground terminal.
2. The reference regulator may be bypassed for operation from a fixed 5-V supply by connecting the Vee and reference output
pins both to the supply voltage. In this configuration, the maximum supply voltage is 6 V.

c

DISSIPATION RATING TABLE

A)

r+
A)

rn

PACKAGE

TA :s 25°C
POWER RATING

DERATING

DERATE

TA - 70°C

FACTOR

ABOVE TA

POWER RATING

J

1000mW

8.2 mw/oe

28°e

656 mW

533 mW

N

1000mW

9.2 mw/oe

41°e

736 mW

598 mW

':1'
CD
CD
r+

en

TA - 85°C
POWER RATING

recommended operating conditions
SG2524

SG3524

UNIT

MIN

MAX

MIN

MAX

Supply voltage, Vec

8

40

8

40

V

Reference output current

0
-0.03

50
-2

mA

Current thru CT terminal

50
0
-2 -0.03

kD

Timing resistor, RT
Timing capacitor, CT

Operating free-air temperature

mA

1.8

100

1.8

100

0.001

0.1

0.001

0.1

~F

-25

85

0

70

°C

electrical characteristics over recommended operating free-air temperature range,
otherwise noted)

Vee

= 20 V (unless

reference section
PARAMETER

TEST CONDITIONSt

Output voltage

SG3524

SG2524
TYP*

MAX

MIN

TYP*

MAX

4.8

5

5.2

4.6

5

5.4

V

20

10

30

mV

Input regulation

VCC - 8 to 40 V

10

Ripple rejection

f - 120 Hz

66

Output regulation

10 = 0 to 20 mA

20

50

20

50

mV

TA = MIN to MAX

0.3

1

0.3

1

%

Vref = 0

100

Output voltage change

with temperature
Short-circuit output current§

TEXAS .."

INSTRUMENTS
POST OFFICE BOX 655012 • DALLAS, TEXAS 75266

dB

66

100

tFor conditions shown as MIN or MAX, use the appropriate value specified under recommended operating conditions.
*AII typical values, except output voltage change with temperature, are at TA = 25°C.
§Ouration of the short circuit should not exceed one second.

2-90

UNIT

MIN

mA

SG2524, SG3524
REGULATING PULSE·WIDTH MODULATORS
electrical characteristics over recommended operating free-air temperature range.
f - 20 kHz (unless otherwise noted)

Vee '"

20

V.

oscillator section
TEST CONDITIONSt

PARAMETER

CT ~ 0.001 ~F.

Frequency

MIN

RT ~ 2 kO

VCC ~ 8 to 40 V,

Frequency change with temperature

TA

~

TA

~

Output amplitude at pin 3

TA ~ 25°C
CT - 0,01 ~F,

%

3.5

%
%
V

0.5

~

25°C

1

MIN to MAX

Output pulse duration (widthl at pin 3

2
TA - 25°C

UNIT
kHz

5

resistance, and capacitance constant

Frequency change with voltage

MAX

450

All values of voltage, temperature,

Standard deviation of frequency§

TYP*

error amplifier section
PARAMETER

fI)

TEST CONDITIONS

SG2524
MIN

SG3524

TYP*

MAX

MIN

TYP*

MAX

UNIT

Input offset voltage

VIC ~ 2.5 V

0.5

5

2

10

mV

Input bias current

VIC ~ 2.5 V

2

10

2

10

~
dB

Open-loop voltage amplification

72

80

60

TA

~

25°C

to

to

3.4

3.4

Common-mode rejection ratio

TA

~

25°C

V

70

70

3

3

Unity-gain bandwidth
Output swing

80

1.8

1.8
Common-mode input voltage range

PI
....

0.5

3.8

0.5

Q)
Q)

.s:.

en

....COCO

C

dB
MHz
3.8

V

output section
PARAMETER

TEST CONDITIONS

MIN

Collector-emitter breakdown voltage
Collector off-state current

TYP*

MAX

0.D1

50

1

2

40
VCE ~ 40 V

Collector-emitter saturation voltage

IC - 50 rnA

Emitter output voltage
Turn-off voltage rise time

Vc

~

20 V,

RC

~

Turn-on voltage fall time

RC

~

~A

V

2 kO

0.2

~s

2 kO

0.1

~

~

17

V
~
V

18

IE

-250

UNIT

comparator section
PARAMETER

TEST CONDITIONS

Maximum duty cycle, each output
Input threshold voltage at pin 9

MIN

TYP*

MAX

45
Zero duty cycle
Maximum duty cycle

%
1

V

3.5
-1

Input bias current

UNIT

~

tFor conditions shown as MIN or MAX, use the appropriate value specified under recommended operating conditions_
N' - - - - - - i7.
*AII typical values, except for temperature coefficients, are at TA = 250C.
§Standard deviation is a measure of the statistical distribution about the mean as derived from the formula u =
n~1 (X n - ')(')2
N-l

TEXAS .."

INSTRUMENTS
POST OFFICE BOX 655012 • DALLAS, TEXAS 75265

2-91

SG2524, SG3524
REGULATING PULSE-WIDTH MODULATORS
electrical characteristics over recommended operating free-air temperature range.
f - 20 kHz (unless otherwise noted)

vee"

20 V.

current limiting section
PARAMETER

TEST CONDITIONS

MIN
-1

Input voltage range leither input)

•

C

Sense voltage at T A

= 25°C

of sense voltage

SG3524
Typt
MAX

PARAMETER

to

+1
190

+1
180

200

210

0.2

V
200

220

Standby current

Pins 1.4,7,8,9,11,14 gronded,
All other inputs and outputs open

Typt

MAX

8

10

t All typical values, except for temperature coefficients, are at TA = 25°C.

~
o

PARAMETER MEASUREMENT INFORMATION
VCC - 8 to 40 V

1

---T--.......---,

15

2 kll

2 kll

2 kll

lW

lW

/0--- 10

"

r----------~II~,C-T~7

13~-4~----~-

...----_>--''WIr----I 6

12~--------~-

OUTPUTS

2 kll ~

3

r---

IOPEN)

161 0 kll ~I----_+---------I 2

14 -

.....- - -.....-15

11

~

1 kll ~-----+--I4

8
2 kll

10 kll
::::::: 0.1 I'F

FIGURE 1. GENERAL TEST CIRCUIT

2-92

TEXAS . "

INSTRUMENTS
POST OFFICE BOX 656012 • DALLAS, TEXAS 76265

mV
mV/oC

0.2

MIN

TEST CONDITIONS
Vee = 40 V,
Pin 2 at 2 V,

UNIT

-1

total device

t/)

CD

MIN

to

Vlpin 2) - Vlpin 1) " 50 mV,
Vlpin 9) = 2 V

Temperature coefficient

CP
r+
CP

::r

SG2524
TYpt MAX

SG2524, SG3524
REGULATING PULSE·WIDTH MODULATORS
PARAMETER MEASUREMENT INFORMATION

Vee

~tf

I
I

2 kll

.,-I--*--

CIRCUIT
UNDER
TEST

I
I
I
I
I
I

I

OUTPUT

OUTPUT

TEST CIRCUIT

---

10%

~Vec

10%

III
...

VOLTAGE WAVEFORMS

FIGURE 2. SWITCHING TIMES

U)

Q)
Q)

TYPICAL CHARACTERISTICS

.c
en

OPEN-LOOP VOLTAGE AMPLIFICATION
OF ERROR AMPLIFIER
vs
FREOUENCY

...caca

OSCILLATOR FREOUENCY
vs
TIMING RESISTANCE

C

1M
--

400 k

-:;r ..0I

60 RF -

£

1 MIl-*+1!IlI--+-++H-HlI--H-l+!lfH--++++f+HI

I

~

50 RF - ~~o kll

f
~

r-.....

100 k

c~

W

~

10 k

.. 0·0

c~..

4k

,

c~

r-....

1 k

400

100

1k

10 k

100 k

1 M

=Vcc -TA

RF is r~~istanc~,,~~om pi,~,,~ to gr~~,~d

_10~~Will-LLUWL-LUillliL~~~~~

hI>

c~ I~I>

I

II.

RF - 30 kll
30 H+t-ftltff-++++HllI--+-f+f+Hk,,+++ffiH+-++IH-llllI

I I I

.~
............ 0. 00

t--

40 k

:Ii::J

40 RF - 100 kll

c~ ..

20

V

7 hif
0.0.1 ;t:-.
hI>

"'0

~hJ:

T 25°C

I I

100

10 M

1

2

4

7 10

20

40

70100

RT- Resistance - kll

Frequency- Hz

FIGURE 3

FIGURE 4

TEXAS . "

INSTRUMENTS
POST OFFICE BOX 855012 • DALLAS. TEXAS 75265

2-93

SG2524, SG3524
REGULATING PULSE-WIDTH MODULATORS
TYPICAL CHARACTERISTICS
OUTPUT DEAD TIME
vs
TIMING CAPACITANCE VALUE
10
VCC - 20 V
TA - 25°C

....

4

..
I

..,~.

,.,. ,,/

..

C

m
....m
en

-

Q

:;

~

0

,/

0.4

~

CD
CD

....
(I)

0.1
0.001

0.004

0.01

0.04

0.1

CT-Capacitance-p.F
FIGURE 5

PRINCIPLES OF OPERATION t
The SG2524 is a fixed-frequency pulse-width-modulation voltage-regulator control circuit. The regulator
operates at a fixed frequency that is programmed by one timing resistor RT and one timing capacitor CT.
RT establishes a constant charging current for CT. This results in a linear voltage ramp at CT, which is
fed to the comparator providing linear control of the output pulse duration (width) by the error amplifier.
The SG2524 contains an on-board 5-V regulator that serves as a reference as well as supplying the SG2524
internal regulator control circuitry. The internal reference voltage is divided externally by a resistor ladder
network to provide a reference within the common-mode range of the error amplifier as shown in Figure
6. or an external reference may be used. The output is sensed by a second resistor divider network and
the error signal is amplified. This voltage is then compared to the linear voltage ramp at CT. The resulting
modulated pulse out of the high-gain comparator is then steered to the appropriate output pass transistor
(Q1 or Q2) by the pulse-steering flip-flop. which is synchronously toggled by the oscillator output. The
oscillator output pulse also serves as a blanking pulse to assure both outputs are never on simultaneously
during the transition times. The duration of the blanking pulse is controlled by the value of CT. The outputs
may be applied in a push-pull configuration in which their frequency is half that of the base oscillator. or
paralleled for single-ended applications in which the frequency is equal to that of the oscillator. The output
of the error amplifier shares a common input to the comparator with the current-limiting and shut-down
circuitry and can be overridden by signals from either of these inputs. This common point is also available
externally and may be employed to control the gain of. or to compensate the error amplifier, or to provide
additional control to the regulator.

tThroughout these discussions. references to the SG2524 apply also to the SG3524.

2-94

TEXAS ."

INSTRUMENTS
POST OFFICE BOX 655012 • DALLAS. TEXAS 75265

SG2524, SG3524
REGULATING PULSE·WIDTH MODULATORS
TYPICAL APPLICATION DATA t
oscillator
The oscillator controls the frequency of the SG2524 and is programmed by RT and CT as shown in Figure 4.

where RT is in kO
CT is in p.F
f is in kHz
Practical values of CT fall between 0.001 and 0.1 p.F. Practical values of RT fall between 1.8 and 100 kO.
This results in a frequency range typically from 140 Hz to 500 kHz.

•
...
U)

Q)
Q)

.c

blanking
The output pulse of the oscillator is used as a blanking pulse at the output. This pulse duration is controlled
by the value of CT as shown in Figure 5. If small values of CT are required, the oscillator output pulse
duration may still be maintained by applying a shunt capacitance from pin 3 to ground.

VJ

...
CO
CO

C

synchronous operation
When an external clock is desired, a clock pulse of approximately 3 V can be applied directly to the oscillator
output terminal. The impedance to ground at this point is approximately 2 kO. In this configuration, RT CT
must be selected for a clock period slightly greater than that of the external clock.
If two or more SG2524 regulators are to be operated synchronously, all oscillator output terminals should
be tied together. The oscillator programmed for the minimum clock period will be the master from which
all the other SG2524s operate. In this application, the CT RT values of the slaved regulators must be set
for a period approximately 10% longer than that of the master regulator. In addition, CT (master) = 2 CT
(slave) to ensure that the master output pulse, which occurs first, has a longer pulse duration and will
subsequently reset the slave regulators.
tThroughout these discussions, references to the SG2524 apply also to the SG3524.

TEXAS ."

INSTRUMENTS
POST OFFICE BOX 655012 • DALLAS. TeXAS 75265

2·95

SG2524, SG3524
REGULATING PULSE·WIDTH MODULATORS
TYPICAL APPLICATION DATA t
voltage reference
The 5-V internal reference may be employed by use of an external resistor divider network to establish
a reference within the error amplifiers common-mode voltage range (1.8 to 3.4 V) as shown in Figure 6,
or an external reference may be applied directly to the error amplifier. For operation from a fixed 5-V supply,
the internal reference may be bypassed by applying the input voltage to both the VCC and VREF terminals.
In this configuration, however, the input voltage is limited to a maximum. of 6 V.
REF
OUT

5 kll

R2

TO POSITIVE
OUTPUT
VOLTAGE

,---"'-REF
OUT

5 kll

R1

5 kll

R2

c

CI)

r+

CI)

CI)

5 kll

':r
CD
CD

TO NEGATIVE
OUTPUT
VOLTAGE

r+

CIl

Vo -

2.5

R1 +R2

V""""R1

R1 R2 _ 2.5 kll
R1+R2

FIGURE 6. ERROR AMPLIFIER BIAS CIRCUITS

error amplifier
The error amplifier is a differential-input transconductance amplifier. The output is available for dc gain
control or ac phase compensation. The compensation node (pin 9) is a high-impedance node (RL = 5 Mil).
The gain of the amplifier is AV = (0.002 11- 1) RL and can easily be reduced from a nominal 10,000 by
an external shunt resistance from pin 9 to ground. Refer to Figure 3 for data.

compensation
Pin 9, as discussed above, is made available for compensation. Since most output filters will introduce
one or more additional poles at frequencies below 200 Hz, which is the pole of the uncompensated amplifier,
introduction of a zero to cancel one of the output filter poles is desirable. This can best be accomplished
with a series RC circuit from pin 9 to ground in the range of 50 kll and 0.001 p.F. Other frequencies can
be canceled by use of the formula f "" 1/RC.

shut-down circuitry
Pin 9 can also be employed to introduce external control of the SG2524. Any circuit that can sink 200 p.A
can pull the compensation terminal to ground and thus disable the SG2524.
In addition to constant-current limiting, pins 4 and 5 may also be used in transformer-coupled circuits to
sense primary current and shorten an output pulse should transformer saturation occur. Pin 5 may also
be grounded to convert pin 4 into an additional shut-down terminal.
tThroughout these discussions, references to the SG2524 also apply to the SG3524.

2-96

TEXAS ...,
INSTRUMENTS
POST OFFICE BOX 655012 • DALLAS, TEXAS 75265

SG2524, SG3524
REGULATING PULSE-WIDTH MODULATORS

TYPICAL APPLICATION DATA t

current limiting
A current-limiting sense amplifier is provided in the SG2524. The current-limiting sense amplifier exhibits
a threshold of 200 mV and must be applied in the ground line since the voltage range of the inputs is
limited to + 1 V to -1 V. Caution should be taken to ensure the -1 V limit is not exceeded by either
input, otherwise damage to the device may result.
Fold-back current limiting can be provided with the network shown in Figure 7. The current-limit schematic
is shown in Figure 8.
El

+VOUT

'""""

~

~~

Rl
;;=r::

SG2524

(-IC.l.

...en

Q)
Q)

.c

en

R2

I

•

Rs

T

(+IC.L.

r.7

~)

...asas

C

v

1

(O(maxl - - (V(sensel +
Rs"
Rl+R2

Vlsense)
lOS - - - - where V(sensel - 20 mV
Rs

FIGURE 7. FOLDBACK CURRENT LIMITING FOR SHORTED OUTPUT CONDITIONS
COMP

CONSTANT-CURRENT
SOURCE

ERROR
AMPLIFIER

(-)C.L.

(+IC.L.

FIGURE 8. CURRENT-LIMIT SCHEMATIC

output circuitry
The SG2524 contains two identical n-p-n transistors, the collectors and emitters of which are uncommitted.
Each transistor has antisaturation circuitry that limits the current through that transistor to a maximum
of 100 mA for fast response.
tThroughout these discussions. references to the SG2524 also apply to the SG3524.

TEXAS . "

INSTRUMENTS
POST OFFICE BOX 655012 • DALLAS, TeXAS 75265

2-97

SG2524, SG3524
REGULATING PULSE-WIDTH MODULATORS
TYPICAL APPLICATION DATA t
general
There are a wide variety of output configurations possible when considering the application of the SG2524
as a voltage regulator control circuit. They can be segregated into three basic categories:
1. Capacitor-diode-coupled voltage multipliers
2. Inductor-capacitor-implemented single-ended circuits
3. Transformer-coupled circuits
Examples of these categories are shown in Figures 9, 10 and 11, respectively. Detailed diagrams of specific
applications are shown in Figures 12 through 15.

01

I+VINI Vref, rz , is given by:

PARAMETER MEASUREMENT INFORMATION
INPUT-"'II\f\r--.....- - - - V Z

INPUT-~~--1~-----VZ

rz

LJ-r----.L,[l. . .
~

R1
TL430
TL430
R2

Vref

l
Vz - V,el 11 +

FIGURE 1. TEST CIRCUIT FOR Vz

2-108

Vref

Rl
R2
1+

I,el' R1

FIGURE 2. TEST CIRCUIT FOR Vz

TEXAS •

INSTRUMENTS
POST OFFICE BOX 655012 • DALLAS, TEXAS 75265

> Vref

TL4301, TL430C
ADJUSTABLE SHUNT REGULATORS
TYPICAL CHARACTERISTICS
CURRENT
vs
VOLTAGE

SMALL-SIGNAL REGULATOR IMPEDANCE
vs
FREQUENCY
3.0
2.8 I - Vz -

160

I.

140 - TA - 25°C

TA - 25°C

c 2.6

.g
.§.

120

I

I

IZM

/

/

c(

I

2.2

!

8

/

2.0
1.8

I

1.6

102

103

104

80

I

CI)

IZ

Q)
Q)

60

/

.c

40

U)

...asas

20

/

1.4
10

II
...

~ 100
C

2.4

~

~

.1

Vz - Vref

Vref

10 5

2

106

IZK
3

C
4

V-Voltage-V

f - Frequency- Hz

FIGURE 3

FIGURE 4

TYPICAL APPLICATION DATA
v + """'--.----.----.- Vo

Vref

V+;------,
V+

-'-~

I
R2

I
I

FIGURE 5. SHUNT REGULATOR

FIGURE 6. SERIES REGULATOR

TEXAS . "

INSTRUMENTS
POST OFFICE BOX 655012 • DALLAS, TEXAS 75265

FIGURE 7. CURRENT LIMITER

2-109

TL4301, TL430C
ADJUSTABLE SHUNT REGULATORS
TYPICAL APPLICATION DATA

V+

V+

I--+-VO
R1
R2

E

~

r+

Dl

en

Vo - Vrel (1

+-~)

Min Vo - Vrel + 5

FIGURE 8. OUTPUT CONTROL OF
A THREE-THERMAL
FIXED REGULA TOR

:::T
CD
CD
r+
In

V+~---+-.--,

R1A

FIGURE 9. HIGHER-CURRENT
APPLICATIONS

Vcc-t_--t_..,

OUTPUT ON
WHEN

R1B

FIGURE 10. CROW 8AR

R1A

R2A

R2A

+

~~: )

High limit = Vrel (1 +

~~~)

Low limit = Vrel (1

+ VBE

FIGURE 11. OVER-VOLTAGEI
UNDER-VOLTAGE
PROTECTION CIRCUIT

2-110

~~: )

Low limit = Vrel (1

+

High limit = Vrel (1

+ ~~~)

+ VBE

FIGURE 12. VCC MONITOR

TEXAS . "

INSTRUMENTS
POST OFFICE BOX 855012 • DALLAS. TEXAS 75285

TL431 M, TL4311, TL431 AI, TL431 C, TL431 AC
ADJUSTABLE PRECISION SHUNT REGULATORS
02410, JULY 1978-REVISED AUGUST 1988

•

TL4311. TL431AI. TL431C. TL431AC ... D PACKAGE

Equivalent Full-Range Temperature
Coefficient , .. 30 ppm/OC

(TOP VIEW)

•

Temperature Compensated for Operation
Over Full Rated Operating Temperature
Range

•

Adjustable Output Voltage

•

Fast Turn-On Response

•

Sink Current Capability ... 1 mA to
100mA

CATHODE D B
ANODE
2
7
ANODE 3
6
NC 4
5

REF
ANODE
ANODE
NC

TL431M ... JG PACKAGE

•

Low 10.2 0 Typl Dynamic Output
Impedance

•

Low Output Noise

•

(TOP VIEW)

CATHODEuB
NC
2
7
NC 3
6
NC 4
5

REF
NC
ANODE
NC

...
U)

Q)
Q)

TL431M ... LD PACKAGE

description

.s::::

(TOP VIEW)

The TL431 and TL431 A are three-terminal
adjustable shunt regulators with specified
thermal stability over applicable industrial and
commercial temperature ranges. The output
voltage may be set to any value between Vref
(approximately 2.5 VI and 36 V with two
external resistors (see Figure 161. These devices
have a typical output impedance of 0.2 O. Active
output circuitry provides a very sharp turn-on
characteristic, making these devices excellent
replacements for zener diodes in many
applications.
The TL431 M is characterized for operation over
the full military temperature range of - 55°C
to 125°C. The TL4311 and TL431AI are
characterized for operation from - 40°C
to 85 °C, and the TL431 C and TL431 AC are
characterized for operation from OOC
to 70°C.

CI)

...
C\'S
C\'S

REF()O
CATHODE

C

()

("

2

3

ANODE

THE ANODE IS IN ELECTRICAL CONTACT WITH THE CASE.
TL4311, TL431AI, TL431C. TL431AC .•. LP PACKAGE
(TOP VIEW)

Q]n~J
[]

CATHODE
ANODE
REF

TL4311, TL431AI. TL431C. TL431AC ... P PACKAGE
(TOP VIEW)

CATHODED'
8
NC 2
7
NC 3
6
NC 4
5

REF
NC
ANODE
NC

NC-No internal connection

symbol
REFERENCE (R)

~M-----

ANODE - - - -..
(A)

PRODUCTION DATA documents contain information

currant 8. of publication data. Products conform to
specifications par the terms of Taxas Instruments
:'~=~i~8t::1~1i ~!:~~ti:r :.r::;:::~:~~ not

CATHODE
(K)

Copyright @ 1982. Texas Instruments Incorporated

TEXAS ",

INSTRUMENTS
POST OFFICE BOX 655012 • DALLAS, TEXAS 75265

2-111

TL431 M. TL4311. TL431 AI. TL431 C. TL431 AC
ADJUSTABLE PRECISION SHUNT REGULATORS
schematic

CATHODE----.-------------~----~--~--._----_.--,

20 pF
REFERENCE

c

...
g)

g)

en

ANODE----~------~----~----~~~--------

:::T

__---"

Component values are nominal.

CI)
CI)

... absolute maximum ratings over operating free-air temperature range (unless otherwise noted)

en

Cathode voltage (see Note 1) ................................................. 37 V
Continuous cathode current range . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. - 100 rnA to 150 rnA
Reference input current range . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. - 50 p.A to 10 rnA
Continuous power dissipation ........................ See Dissipation Rating Tables 1 and 2
Operating free-air temperature range: TL431 C, TL431 AC . . . . . . . . . . . . . . . . . . . . .. 0 DC to 70°C
TL4311, TL431AI ..................... _40DC to 85 DC
TL431M .......................... -55°C to 125°C
Storage temperature range ......................................... - 65°C to 150 DC
Lead temperature 1,6 mm (1/16 inch) from case for 60 seconds: LD or JG package. . . . . .. 300°C
Lead temperature 1,6 mm (1/16 inch) from case for 10 seconds: D, LP, or P package ..... 260°C
NOTE 1: Voltage values are with respect to the anode terminal unless otherwise noted.

DISSIPATION RATING TABLE 1-FREE-AIR TEMPERATURE
PACKAGE

D

JG

TA s 25'C
POWER RATING
825 mW
1050mW

DERATING FACTOR
ABOVE TA - 25 0 C
6.6 mW/oC
8.4 mW/oC

TA - 70'C
POWER RATING

TA - B5 0 C
POWER RATING

TA - 125 0 C
POWER RATING

528 mW

672 mW

429 mW
546 mW

210mW
55mW

LD
LP

275 mW

2.2 mW/oC

176mW

143 mW

775 mW

6.2 mW/'C

496 mW

403mW

P

1000 mW

8.0 mW/'C

640mW

520 mW

DISSIPATION RATING TABLE 2-CASE TEMPERATURE
PACKAGE
LD

TC s 25°C
POWER RATING
1550 mW

DERATING FACTOR
ABOVE TC - 25 0 C
12.4 mW/'C

TC - 125°C
POWER RATING

recommended operating conditions
Cathode voltage, VKA
Cathode current, IK (for regulation)

2-112

TEXAS •

INSTRUMENTS
POST OFFICE BOX 655012 • DALLAS. TEXAS 75265

310mW

electrical characteristics at 25 DC free-air temperature (unless otherwise noted)
TEST

PARAMETER
Reference input voltage

Vref

Deviation of reference input voltage
Vref{dev)
AVref

--

over full temperature range t

input voltage to the change
in cathode voltage

Iref

Reference input current

over full temperature ranget:
Minimum cathode current

~

~z

i ~~:::i
~c:

§~.

IK~10mA.

2

IK = 10 rnA

2

MIN

TYP

MAX

MIN

TA = full range t

!4VKA

~

10 V - Vref

14VKA

~

36V - 10V

'K ~ 10 rnA.

Rl~10kn.

R2 =

00

'K ~ 10 rnA.

Rl~10kn.

R2 =

00,

22

5

30

-1.4

-3

-1.4

-2.7

-1

-2.3

-1

-2

2

8

1

TA = full range t

4

17

-1.4 -2.7
-1

UNIT
mV
mV
mV

-

-2

V

2

4

2

4

pA

0.8

2.5

0.4

1.2

pA

1

VKA = Vref

0.4

1.5

0.4

1

0.4

1

rnA

VKA ~ 36 V. Vref ~ 0

0.1

3

0.1

1

0.1

1

pA

IZkal

Dynamic impedance§

1

0.2

0.9

0.2

0.5

0.2

0.5

IK=lmAto100mA,

VKA = Vref.
f

:s 1 kHz

n

t Full temperature range is - 55°C to 125 DC for the TL431 M. - 40DC to 85 DC for the TL431I. and 0 DC to 70 DC for the TL431 C.
:t: The deviation parameters Vref(dev) and Iref(dev) are defined as the differences between the maximum and minimum values obtained over the rated temperature range. The average full-range
temperature coefficient of the reference input voltage, C1:Vre f' is defined as:

-+--,

MaXVreftc1(ppm) _

IO:Vref I \oc

-

( V ref(dev)D ) X 106
Vref @ 25 C..


TEST

PARAMETER
Reference input voltage

Vrelldev)

over full temperature range t

aVrel

-aVKA

in cathode voltage

Irel

Reference input current
over full temperature range:J:

Minimum cathode current

~
;or;;i

~~

~~

VKA ~ Vrel,

IK

~

10mA

1

VKA ~ Vrel,

IK

~

10mA,

2

IK

2

Deviation of reference input current

Irelldev)

1

Ratio of change in reference
input voltage to the change

Cl"'"

TL431 AI

TEST CONDITIONS

CIRCUIT

Vrel

Deviation of reference input voltage

z

:1:10-1

electrical characteristics at 25°C free-air temperature (unless otherwise noted I

~

10 rnA

IK - 10 rnA,
IK

~

10 rnA,

I

I

~

10 V - Vrel

aKVA

~

36 V - 10 V

R1 - 10 k!l,

R2 - co

R1

R2

~

10 k!l,

~

UNIT

MIN

TYP

MAX

MIN

TYP

MAX

2470

2495

2520

2470

2495

2520

mV

5

25

4

15

mV

-1.4

-2.7

-1.4

-2.7

-1

-2

-1

-2

2

4

2

4

~A

2.5

0.8

1.2

~A

TA ~ lull range t

aVKA

TL431AC

co,

mV

-

V

2

TA ~ lull range t

0.8

1

VKA ~ Vrel

0.4

0.7

0.4

0.6

rnA

VKA ~ 36 V, Vrel ~ 0

0.1

0.5

0.1

0.5

~A

0.2

0.5

0.2

0.5

!l

'min

for regulation

loff

Off-state cathode current

3

IZkal

Dynamic impedance §

1

VKA ~ Vrel,

IK

~

1 rnA to 100 rnA,

*The deviation parameters V ref(dev) and Iref(dev) are defined as the differences between the maximum and minimum values obtained over the rated temperature range. The
average full-range temperature coefficient of the reference input voltage, aVref. is defined as:

--;;c

I aVrel I (ppm) ~

aTA

M~.~~~
I

MinVref

-

-

-

-

-

Vrelldevl

4-.:l
I

I.-- aTA -----.I
where d T A is the rated operating free-air temperature range of the device.
aVref can be positive or negative depending on whether minimum Vref or maximum Vref, respectively, occurs at the lower temperature.
§The dynamic impedance is defined as:

IZkal

I"'" I"'"

m.r;:..
."W

:::ann

m:l:lo

en

Ci

:2

en
c

:2
-I

:::a
m
~

C

tFull temperature range is -40°C to 85°C lor TL431AI and OOC to 70°C lor TL431AC.

Vref(dev! )x 106
Vrel @ 25°C

-1:1:10
:1:10:=-1

:z:

f '" 1 kHz

(

c:...r;:..
W

C
en-

~ a~I:A

When the device is operating with two external resistors. see figure 2. the total dynamic impedance of the circuit is given by:

av , which is approximately equal to I zka I ( 1 + R2
R1)
I z' I ~ ~

E
CI

:::a
en

TL431 M, TL4311, TL431 AI, TL431 C, TL431 AC
ADJUSTABLE PRECISION SHUNT REGULATORS
PARAMETER MEASUREMENT INFORMATION
INPUT -'WI.--.....- - VKA

INPUT --"""""I\r-~t----VKA

R1

Vr.f

R2

!

"="

FIGURE 1. TEST CIRCUIT FOR VKA

= Vref

VKA - Vref (1

+.!!! )+
R2

FIGURE 2. TEST CIRCUIT FOR VKA

>

IrefoR1

PI
...
(/)

Vref

Q)
Q)

J:

INPUT-'WI,,---..---VKA

en

...
C'CI

C'CI

C

FIGURE 3. TEST CIRCUIT FOR loff

TYPICAL CHARACTERISTICS
CATHODE CURRENT

CATHODE CURRENT
vs

vs

CATHODE VOLTAGE

CATHODE VOLTAGE
800

150

VKA - Vref
TA - 25°C

VKA - Vref
125 r-TA - 25°C



III

0
-75 -50 -25

0

25

50

---

I

C>

!'l
c;

20

>

"
·0


"I

!---

:l

~

«

Vref - 2550 mVt

I 2560

C>

!'l 2540
c;

4 k 10 k 40 k 100 k

f - Frequency - Hz

FIGURE 6

>

IK = 10 mA
TA = 25°C

......

30

I:

..

V

j

I~~~ ~ ~:~~I

'"

40

0

r+

CD
CD

=

50

~

36 V
0

~

"C

U

Q)

=

u

C
Q)

I
vKA
Vref

50

75

100

125

i!!
:;
u

S0.

3

.5

""
i!!

I:

2

-ta:

--------r-

-r-- I--

.L

~

o
-75 -50 -25

T A - Free-Air Temperature- °C

0

25

50

75

100 125

TA -Free-Air Temperature- °C

FIGURE 8

FIGURE 9

tFor TL4311, TL431AI, TL431C, and TL431AC, the data applies only for the portions of the curves that lie within their recommended
operating temperature ranges.
:l:O ata is for devices having the indicated value of Vref at IK = 10 rnA, TA = 25°C.

2-116

TEXAS •
INSTRUMENTS
POST OFFICE BOX 655012 • DALLAS, TEXAS 75265

TL431 M, TL4311, TL431 AI, TL431 C, TL431 AC
ADJUSTABLE PRECISION SHUNT REGULATORS
TYPICAL CHARACTERISTICS

~

o

i>'"

-5

.

CHANGE IN REFERENCE INPUT VOLTAGE
vs
CATHODE VOLTAGE

'"

-10

~

::J

Q.

.5

-15

il
!
~

-25

~

.

-30

I

-35

~

-40

.5

I

\

I

!

0.3

I

IK - 10 rnA
TA = 25°C
CO

.

~

c

~

-20

5

10

0.25

~

15

20

CI)

~

Q)
Q)

~

25

0.1

J:

I
Iii

Ul

....

""

30

35

ca
ca

...!!. 0.05

~

C

o
40

-75 -50 -25

.5

4

50

75

100 125

FIGURE 11

TA - 25°C
IK - 1 rnA to 100 rnA

40

.

25

DYNAMIC IMPEDANCE
vs
FREQUENCY

100
70

20

o

TA -Free-Air Ternperature- °C

FIGURE 10

.,I
"c
".

II

c

VKA-Cathode Voltage-V

CO

I-- I--

'-

0.2

1
.5
" 0.15
'..e
~

o

VKA - Vref
IK - 1 rnA to 100 rnA
f :$ 1 kHz

I
~

.<:

o

DYNAMIC IMPEDANCE
vs
FREE-AIR TEMPERATUREt

1 kO
r - - -__--~~~.----e------OUTPUT

If

10
7

Q.

.So!

.

E

c

500

2

c>I

1
0.7

....

0.4

.

~

L-~~------~'---

0.2

__------GND

TEST CIRCUIT FOR DYNAMIC IMPEDANCE

0.1
1 k

10 k

100 k

1 M

10 M

f- Frequency - Hz

FIGURE 12
tFor TL4311, Tl431 AI, TL431C, and TL431AC, the data applies only for the portions of the curves that lie within their recommended
operating temperature ranges.

TEXAS

~

INSTRUMENlS
POST OFFICE BOX 655012 • DALLAS, TEXAS 75265

2-117

TL431M, TL4311, TL431AI, TL431C, TL431AC
ADJUSTABLE PRECISION SHUNT REGULATORS
TYPICAL CHARACTERISTICS
SMALL-SIGNAL VOLTAGE AMPLIFICATION

vs
FREQUENCY

70

y~"~ 2~~~1

60

IK -, 10 mA

III

....
I

I:

i
;S
...E
c ...
r+
u

c(

D)
D)

en

':r
CD
CD

"-

50

\

15 kll
91'F

30

\

20

1!0
> 10
I
>
c(

+
8.25 kll

\

~---e----e--'-~~--GND

0

'\
TEST CIRCUIT FOR VOLTAGE AMPLIFICATION

-10

fI)

230 II

40

CD

r+

.----4~---....--OUTPUT

10 k

1 k

100 k

1M

10 M

f- Frequency- Hz

FIGURE 13
PULSE RESPONSE

6
TA

~

25°C

l 1
INPUT

> 5

INPUT
MONITOR

I

220 II
...--.....--....-..JV\"."..-....--OUTPUT

:l

~

4

'[

3

~

I
I

..
s

PULSE
GENERATOR
f - 100 kHz

OUTPUT

S

o
1!

2

I

50 II

J

~

o

o

TEST CIRCUIT FOR PULSE RESPONSE

2

3

4

567

FIGURE 14

2-118

TEXAS . "

INSTRUMENTS
POST OFFICE BOX 655012 • DALLAS, TEXAS 75265

TL431 M, TL4311, TL431 AI, TL431 C, TL431 AC
ADJUSTABLE PRECISION SHUNT REGULATORS
TYPICAL CHARACTERISTICS
1500

1500
R1 10 kO

IK'

+

CL

CL

V+

V,e!

•

R2

...
II)

TEST CIRCUIT FOR CURVES B, C, AND D BELOW

TEST CIRCUIT FOR CURVE A BELOW

Q)
Q)

STABILITY BOUNDARY CONDITIONS

.s::::

100
90
80

«

70

i:
~
::I

60

E
I

....

U

A VKA
B VKA
C VKA
DVKA

-

CJ)

V,e!
5 V @ IK - 10 mA
10 V @ IK - 10 mA
15V@IK = 10mA

...
CO
CO

C

At

STABLE

Bt

~ ct

50

0

.<:

10
u

40

~

30

I

//

STABLE

/

1\\

/ /
II / 1/\ \
l17/ \\ \\
ot

20
10
TA - 25°C
0
10 pF
100 pF

1000 pF

0.01 j--Vout
R2

Vout - V,at (1 +

~)

Min Vout - V,et + 5 V

FIGURE 18. SERIES REGULATOR

2-120

FIGURE 19. OUTPUT CONTROL OF
A THREE-TERMINAL
FIXED REGULATOR

TEXAS . "

INSTRUMENTS
POST OFFICE BOX 655012 • DALLAS, TEXAS 75265

TL431 M. TL4311. TL431 AI. TL431 C. TL431 AC
ADJUSTABLE PRECISION SHUNT REGULATORS

TYPICAL APPLICATIONS
V+-f\M~"""--""----it---Vout

o-....--~~_Vout

V+

R1

R2
R2

fI
....
II)

Q)
Q)

FIGURE 21. CROW BAR

FIGURE 20. HIGHER-CURRENT
SHUNT REGULATOR

(/)

....COCO

V+~.----.---e----,

R1A

.c

o

R1B
OUTPUT ON WHEN
LOW
HIGH
LIMIT
-~

,I

-

UJ
CO
CO

68 n,
2W

r---------,

CD
CD

.r:.

15V

C

OUTPUT

CL = 15 pF
(includes probe and
jig capacitance)

I
I
I
I

I

:...... _ _ _ _ _ _ _ _ ...JI
OUTPUT VOLTAGE WAVEFORM

TEST CIRCUIT

FIGURE 3. COMMON-EMITTER CONFIGURATION
15V

r--------,

I
I
I
I

(EACH OUTPUT
CIRCUIT)

J

I
r--o----~

I
I
I
I

I

'----<0-<....- -...-

OUTPUT

I

,
I
l _________ J

68 n,
2W

CL = 15 pF
(includes probe and

jig capacitance) '--....- - '
OUTPUT VOLTAGE WAVEFORM

TEST CIRCUIT

FIGURE 4. EMITTER-FOLLOWER CONFIGURATION

TEXAS

~

INSTRUMENTS
POST OFFICE BOX 655012 • DALLAS, TEXAS 75265

2-129

TL493. TL494. TL495
PULSE-WIDTH-MODULATION CONTROL CIRCUITS
TYPICAL CHARACTERISTICS
OSCILLATOR FREQUENCY AND
FREQUENCY VARIATIONt vs
TIMING RESISTANCE
100 k
Vee = 15V
TA ~ 25'e

40 k
-~%
N

:I:

,

10 k

I

4k

C

m
r+
m

~

400

0

100

=aIn

:::r

CD
CD

"'~
"'~

I

1k

olb~
'00,

0. 0 ,

I

0.,

K'

-

-

"'~

II.

t/)

--

"
0%- ~

,

>
u
c
:s
cr
!

.

1%

"" . ,

~,1ft

I
I

= 1%

"'~

40

r+

en

10

II
1 k

I'..

40 k 100 k
400 k 1 M
4 k 10 k
RT- Timing Resistance-!)

FIGURE 5

AMPLIFIER VOLTAGE AMPLIFICATION
vs
FREOUENCY

100
90
III

"cI

80

-

'\

70

0

'1; 60
=E

is.

E

"-

" '"
~

50

.

«

Ol

l! 30
0

>

Vee = 15V
!!NO = 3 V TA = 25'e

r-....

'\.

20

"\.
'\.

o

"\.

1

10

100
1 k
10 k
f- Frequency- Hz

1 M

FIGURE 6
fFrequency variation (af) is the change in oscillator frequency that occurs over the full temperature range.

2-130

TEXAS . "

INSTRUMENTS
POST OFFICE BOX 655012 • DALLAS, TeXAS 75265

TL496C
9-VOLT POWER-SUPPLY CONTROLLER
02486. AUGUST 1978-REVISED FEBRUARY 1988

DB

D OR P PACKAGE

•

Internal Step-Up Switching Regulator

•

Fixed g-Volt Output

•

Charges Battery Source During TransformerCoupled-Input Operation

•

Minimum External Components Required
(1 Inductor, 1 Capacitor, 1 Diode)

•

,- or 2-Cell-lnput Operation

(TOP VIEW)

FEEDBACK
2C
INPUT { lC
T

2
3
4

7
6
5

OUTPUT
GND
SW
GND

Pins 5 and 7 are connected together internally.

description
The TL496 power supply control circuit is designed to provide a 9-volt regulated supply from a variety
of input sources. Operable from a 1- or 2-cell battery input, the TL496 performs as a switching regulator
with the addition of a single inductor and filter capacitor. When ac coupled with a step-down transformer,
the TL496 operates as a series regulator to maintain the regulated output voltage and, with the addition
of a single catch diode, time shares to recharge the input batteries.
The design of the TL496 allows minimal supply current drain during stand-by operation (125 /LA typical).
With most battery sources this allows a constant bias to be maintained on the power supply. This makes
power instantly available to the system thus eliminating power-up sequencing problems.

•
...en

CD
CD
J:

Ul

...
CO
CO

C
functional block diagram
TINPUT~(4~)__~__-r--~~---,

______-.________-.~__~(8)

e-__________-+__________

~--_(~1)

OUTPUT

FEEDBACK

...._ _ _ _ _ _--'(6.;.:.) SWITCH

(loV) (1722.)-----<.----GSWi~fiiNiGl
2C INPUT~

(1.5·V) (3)
lC INPUT~--~--_t~~~~~

NOTE 1: Pins 5 and 7, though connected together internally, must both be terminated to ground to ensure proper circuit operation.

absolute maximum ratings
Input voltage:
Pin 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.5 V
Pin 3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.5 V
Pin 4 ............................................ , ................... 20 V
Output voltage (Pin 6) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 12 V
Diode reverse voltage (Pin 8) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 12 V
Switch current (Pin 6) ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 1.2 A
Diode current (Pin 8) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 1.2 A
Continuous total dissipation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. See Dissipation Rating Table
Operating free-air temperature range . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. O°C to 70°C
Storage temperature range ......................................... - 65°C to 1 50°C
Lead temperature 1,6 mm (1/16 inch) from case for 10 seconds. . . . . . . . . . . . . . . . . . . . .. 260°C

PRODUCTION DATA documenls oontain information
current a. of publication data. Preducts cDn'orm to
specifications par the tarms of Taxa. Instruments

:::::i~at::I':.7~ ~r::I:~i:; ~r:.a;:.:~:.s

not

Copyright © 1982, Texas Instruments Incorporated

TEXAS . "

INsrRUMENlS
POST OFFICE BOX 655012 • DALLAS, TEXAS 75265

2-131

TL496C
9-YOLT POWER-SUPPLY CONTROLLER
DISSIPATION RATING TABLE
PACKAGE

DERATING

TA '" 25·C
POWER RATING

FACTOR

TA - 70·C
POWER RATING

D

725mW

5.B mW/oC

464 mW

P

1000 mW

B.O mW/oC

640 mW

recommended operating conditions
MIN

MAX

Input voltage, one-cell operation (pins 2 and 3 to ground)

1.1

1.5

V

Input voltage, two-cell operation (pin 2 to ground)

2.3

3

V

20

V

Input voltage, one-cell or two-cell operation (pin 4 to ground)

C

I»
r+
I»
t/)

electrical characteristics at 25 DC free-air temperature
series regulator section (input is pin 4)
PARAMETER

::r

Dropout voltage

r+

Regulated output voltage

CD
CD

m

VO+2

UNIT

TEST CONDITIONS
VI - 5 V,

10 -

MIN

-50 rnA

VI= 20 V
VI = 20 V,
Pin 1 shorted to pin 8

TYP

MAX

1.5

2

10 = -50 ~A
10 = -BO rnA

9.5

10.1

11.2

9.0

10.0

11.0

10 = -50 ~A
10 = -BO rnA

B.5

9.0

9.7

6.7

B.6

9.5

UNIT
V

V

Standby current (pin 41

VI - 20 V,

Pin B at 12 V

400

~A

Reverse cur.rent thru pin 4

VI = -1.5V,

1 rnA into pin 8

-25

~A

output switch
PARAMETER
VCE(satl

TEST CONDITIONS

Collector-emitter saturation voltage

800 rnA into pin 6,

MIN

Pin 2 at 2.25 V

TYP

MAX

0.35

0.6

TYP

MAX

diode (pin 6 to pin 8)
PARAMETER

TEST CONDITIONS

Forward voltage

IF = 1.5 A

Reverse current thru pin 6

Pin 6 at 0 V,

MIN

1.6
1 rnA into pin 8

2.5
-20

control section
PARAMETER

TEST CONDITIONS

TYP

MAX

UNIT

60

100

rnA

Pins 2 and 6 at 3 V

40

~A

Pins 2 and 6 at 3 V

400

~A

On-state current (pin 2)

Pins 1 and B at 0 V, Pin 2 at 3 V

Standby current (pin 11

Pin 1 at B.65 V,

Standby current (pin 2 and 61

Pin 1 at B.65 V,

Start-up current (current into
pin 6 to initiate cycle)

2-132

Pins 1, 2, 6 and B at 2.25 V

TEXAS ",
INSTRUMENTS
POST OFFICE BOX 655012 • DALLAS, TEXAS 75266

MIN

16

rnA

TL496C
9·VOLT POWER·SUPPLY CONTROLLER
TYPICAL APPLICATION DATA
CIRCUIT COMPONENT INFORMATION
D1: 1N4001
CF: 330 to 4 70 ~F, 10 V, electrolytic
L: 40 to 50 ~H, Q = 3, R < 0, 15 Il
T1: Vsec = 6.B V RMS typ., Rsec = 11 Il typo

}-....- -.....>-- OUTPUT

2C

II
...

T

o

~------~-~~-------~e--GND

CD
CD

FIGURE 1. ONE·CELL OPERATION

.c

CIRCUIT COMPONENT INFORMATION
D1: 1N4001
CF: 330 to 470 ~F, 10 V, electrolytic
L: 40 to 50 ~H, Q = 3, R < 0, 15 Il
T1: Vsec = 6.B V RMS typ., Rsec = 11 Il typo

til

...
CO
CO

C

T1

JII~>+----<

2C

} - - -. .- - OUTPUT

OUTPUT
TL496

T

~;~-------"-""'~-----------GND

FIGURE 2. TWO·CELL OPERATION

typical electrical characteristics for circuits above
PARAMETER
Input current

Output voltage

ONE·CELL OPERATION (FIGURE 1)
No load

TWO·CELL OPERATION (FIGURE 2)

125 uA

125 uA

525 rnA

405 rnA

Without T1

7.2 V

B.6 V

WithT1

B.6 V

10V

40 rnA

BO rnA

RL=1201l

Output current capability
Efficiency
Battery life (AA NiCad) no load

66%

66%

60 days

166 days

TEXAS .."
INSTRUMENTS
POST OF.FICE BOX 655012 • DALLAS, TEXAS 75265

2-133

TL496C
9·VOLT POWER·SUPPLY CONTROLLER
functional description
The TL496 is designed to operate from either a single-cell or two-cell source. To operate the device from
a single-cell (1.1 V to 1.5 V) the source must be connected to both inputs 1 C and 2C as shown in Figure 1.
For two-cell operation (2.3 V to 3.0 V), the input is applied to the 2C input only and the 1 C input is left
open (see Figure 2).
battery operation

C

I»

!it

The TL496 operates as a switching regulator from a battery input. The cycle is initiated when a low voltage
condition is sensed by the internal feedback (the thresholds at pin 1 and pin 8 are approximately 7.2 and
8.6 volts respectively). An internal latch is set and the output transistor is turned "on." This causes the
current in the external inductor (L) to increase linearly until it reaches a peak value of approximately
1 ampere. When the peak current is sensed the internal latch is reset and the output transistor is turned
"off." The energy developed in the inductor is then delivered to the output storage capacitor through the
blocking diode. The latch remains in the off state until the feedback signal indicates the output voltage
is again deficient.

(f)

transformer-coupled operation

CD
CD

The TL496 operates on alternate half cycles of the ac input during transformer-coupled operation to, first,
sustain the output voltage and, second, recharge the batteries. The TL496 performs like a series regulator
to supply charge to the output filter/storage capacitor during the first half cycle. The output voltage of
the series regulator is slightly higher voltage than that created by the switching circuit; this maintains the
feedback voltage above the switching regulator control circuit threshold. This effectively inhibits the
switching control circuitry. During the second half cycle an external diode (1 N4001) is used to clamp the
negative going end of the transformer secondary to ground thus allowing the positive-going end (end
connected to V + side of battery) to pump charge into the stand-by batteries.

::r

...
I/)

2-134

TEXAS •

INSTRUMENTS
POST OFFICE BOX 655012 • DALLAS, TEXAS 75265

TL497 AM, TL497 AI, TL497 AC
SWITCHING VOLTAGE REGULATORS
02225. JUNE 1976- REVISED OCTOBER 1988

•
•
•
•
•
•
•
•

High Efficiency ... 60% or Greater
Output Current ... 500 mA

(TOP VIEWI

Input Current Limit Protection
TTL Compatible Inhibit
Adjustable Output Voltage
Input Regulation ... 0.2% Typ
Output Regulation ... 0.4% Typ
Soft Start-up Capability

TL497AM ... J PACKAGE
TL497AI. TL497AC ... D. J. OR N PACKAGE

COMP INPUT
INHIBIT
FREQ CONTROL
SUBSTRATE
GND
CATHODE
ANODE

VCC
CUR LIM SENS
BASE DRIVEt
BASEt
COL OUT
NC
EMIT OUT

NC - No internal connection

t The Base pin (#111 and Base Drive pin (#121 are used for device

description

testing only. They are not normally used in circuit applications
of the device.

II
...
U)

CL)
CL)

The TL497 A incorporates on a single monolithic chip all the active functions required in the construction
of a switching voltage regulator. It can also be used as the control element to drive external components
for high-power-output applications. The TL497 A was designed for ease of use in step-up. step-down. or
voltage inversion applications requiring high efficiency.

.c

The TL497 A is a fixed-on-time variable-frequency switching voltage regulator control circuit. The on-time
is programmed by a single external capacitor connected between the frequency control pin and ground.
This capacitor. CT. is charged by an internal constant-current generator to a predetermined threshold. The
charging current and the threshold vary proportionally with Vcc. thus the one time remains constant over
the specified range of input voltage (5 to 12 V). Typical on-times for various values of CT are as follows:

C

tJ)

...caca

TIMING CAPACITOR. CT (pF)
ON-TIME ( s)
The output voltage is controlled by an external resistor ladder network (R1 and R2 in Figures 1. 2.
and 3) that provides a feedback voltage to the comparator input. This feedback voltage is compared to
the reference voltage of 1.2 V (relative to the substrate pin) by the high-gain comparator. When the output
voltage decays below the value required to maintain 1.2 Vat the comparator input. the comparator enables
the oscillator circuit. which charges and discharges CT as described above. The internal pass transistor
is driven on during the charging of CT. The internal transistor may be used directly for switching currents
up to 500 mA. Its collector and emitter are uncommitted and it is current driven to allow operation from
the positive supply voltage or ground. An internal Schottky diode matched to the current characteristics
of the internal transistor is also available for blocking or commutating purposes. The TL497 A also has
on-chip current-limit circuitry that senses the peak currents in the switching regulator and protects the
inductor against saturation and the pass transistor against overstress. The current limit is adjustable and
is programmed by a single sense resistor. RCL. connected between pin 14 and pin 13. The current-limit
circuitry is activated when 0.7 V is developed across RCL. External gating is provided by the inhibit input.
When the inhibit input is high. the output is turned off.
Simplicity of design is a primary feature of the TL497 A. With only six external components (three resistors.
two capacitors. and one inductor). the TL497 A will operate in numerous voltage conversion applications
(step-up. step-down. invert) with as much as 85% of the source power delivered to the load. The TL497 A
replaces the TL497 in all applications.
The TL497 AM is characterized for operation over the full military temperature range of - 55 ac to 125 °C.
the TL497 AI is characterized for operation from - 25°C to 85 ac. and the TL497 AC from O·C to 70°C.

PRODUCTION DATA documonl. conlain informalion
currant as of publication date. Products conform to
spacifications par the terms of Taxas Instruments

==~~i~ai~:1~1i ~~:t;:~i:r :'fO::::::£::-'~S nat

Copyright @ 1983, Texas Instruments Incorporated

TEXAS . "

INSTRUMENTS
POST OFFICE BOX 655012 • DALLAS, TeXAS 76265

2-135

TL497 AM. TL497 AI. TL497 AC
SWITCHING VOLTAGE REGULATORS
functional block diagram
BASE

~(_11~I_t______________________________________-,

BASE DRIVE ...:(..:.;12::.:_t________________________________-,

CUR LIMSENS
F REQ CONT ..:;(3:.;.1________________________-1

•

INHIBIT
COMP INPUT

...

=-CDCD

...

='______________________--,
(101 COL OUT

.l!!----------------f,

SUBSTRATE

C
m
m

en

OSCILLATOR

EMIT OUT

CATHODE...:(~61~______________~~~'----------------------------..:.;(7~1 ANODE
t The Sase pin (#111 and Sase Drive pin (#12) are used for device testing only. They are not normally used in circuit applications of the device.

absolute maximum ratings over operating free-air temperature range (unless otherwise noted)

(II

Input voltage. VCC (see Note 1) . _ ..... _ ... _ ... _ ........ _ .. _ . _ ..... _ .. _ ..... _ .. 15 V
Output voltage ...... _ ... _ .. _ ... _ .... _ ... _ ......... _ .. _ . _ .. _ .. _ ... _ ...... _ _ 35 V
Comparator input voltage _ .. _ .. _ .... __ ... _ ... _ ........ _ .. _ . _ .. __ . _ .. _ ..... _ . _. 5 V
Inhibit input voltage ............. _ . __ . _ ... ____ ..................... _ ..... _ . .. 5 V
Diode reverse voltage _ . _...... _ ................... _ ..... _ ..... _ . _ . . . . . . . . . .. 35 V
Power switch current. __ .. _ ..... _ ... _ . _ ... _ ...... _ ..... _ ........ _ . __ .... __ 750 mA
Diode forward current . ___ .. _ . _ ..... _ ...... _ . _ ... _ ... _ . __ ....... _ . . . . . . . .. 750 mA
Continuous total dissipation ..... _ ..... _ ... _ .... __ ... _ ..... _. See Dissipation Rating Table
Operating free-air temperature range: TL497 AM .... _ ....... _ .. _ .... _ . . .. - 55 DC to 125 DC
TL497 AI ... _ ..... _ .. _ .. _ . _ .. _ .. _ . .. - 25 DC to 85 DC
TL497AC . _ . _ ......................... ODC to 70 DC
Storage temperature range ......................................... - 65 DC to 150 DC
Lead temperature 1.6 mm (1/16 inch) from case for 60 seconds: J package ............ 300 DC
Lead temperature 1.6 mm (1/16 inch) from case for 10 seconds: 0 or N package ........ 260 DC
NOTE 1. All voltage values except diode voltages are with respect to network ground terminal.

DISSIPATION RATING TABLE
PACKAGE

TA s 25°C
POWER RATING
950mW

DERATING
FACTOR
7.6 mW/oe

DERATE
ABOVETA

0
J (TL_ AM)
J (TL_AIl

1000 mW
1000 mW

11.0mW/oe

59°e

8.2 mW/oe

28°e

N

1000 mW

9.2 mW/oe

41°e

2-136

25°e

TA - 70°C
POWER RATING

TA - 85°C
POWER RATING

608 mW
880mW

494mW

656 mW
736 mW

533 mW

TEXAS . "

INSTRUMENTS
POST OFFICE BOX 655012 • DALLAS, TeXAS 75265

715mW
598 mW

TA - 125°C
POWER RATING
275 mW

TL497AM, TL497AI, TL497AC
SWITCHING VOLTAGE REGULATORS
recommended operating conditions
MIN

MAX

Input voltage, VI

4.5

12

High-level inhibit input voltage, VIH

2.5

Output voltage

V
V

O.B

Low-level inhibit input voltage, Vil

I
I

UNIT

Step-up configuration Isee Figure 11
Step-down configuration (see Figure 2)

I Inverting regulator (see Figure 3)

VI+2

30

Vref

VI-l
-25

-Vref

V
V

Power switch current

500

rnA

Diode forward current

500

rnA

electrical characteristics at specified free-air temperature, VI ~ 6 V (unless otherwise noted)
PARAMETER
High-level inhibit input current

VI(I)

= 5V
=0V

Low-level inhibit input current

VI(I)
VI

Comparator input bias current

VI

= 4.5 V to
=6V

VI

= 4.5

110
VPO

Switch off-state current

VI

= 4.5

V, Vo

Current-limit sense voltage

VI = 6 V
10 - 10 rnA

Diode forward voltage

10

On-state supply current

Off-state supply current

TYP*

MAX

0.8

1.5

Full range

6 V

Full range

1.14

Full range

=
=

100 rnA
500 rnA

=

30 V

25°C

5

20

1.20

1.26

40
0.13

Full range
25°C

10

MAX

O.B

1.5

rnA
~A

5

10

1.20

1.32

V

100

40

100

~A

0.2

0.13

LOB

50
1

0.75

0.2
0.85

10

500
0.45

50
200

0.45

0.95

1
0.75

Full range

0.9

1.1

0.9

1

Full range

1.33

1.75

1.33

1.55

500 ~A

Full range

10 - 200 ~A

Full range

11

14

11

14

30

25°C
25°C
Full range

16
6

9

V
~A

V
V

V

30

Full range

•

0.B5

100 rnA

10

UNIT

TYP*

1

Full range
25°C
Full range

TL497AC
MIN

500 rnA

10
Diode reverse voltage

=
=
=

MIN

Full range

Comparator reference voltage

Switch on-state voltage

Tl497AM, TL497AI

TEST CONDITIONSt

15
6

11

9
10

rnA
rnA

tFull range for Tl497AM is -55°C to 125°C, for TL497AI is -25°C to 85°C, and for TL497Ae is ooe to 70°C.
= 25°C.

*All typical values are at T A

TEXAS . "

INSTRUMENTS
POST OFFICE BOX 655012 • DALLAS, TEXAS 75265

2-137

TL491AM, TL491AI, TL491AC
SWITCHING VOLTAGE REGULATORS
TYPICAL APPLICATION DATA
RCL

DESIGN EQUATIONS

L

I1

14

Vo

I

r-

10

13

8

TL497

E

1
I

r-----

4

5

ICTt

I

I

I

1 1

2

3

1

6

= 21 0 max

7

IPK

•

VI
l (!,H) = IPK ton(!'s)

Choose l (50 to 500 !,Hl. calculate
ton (25 to 150 !'s)

R2 1.2 kO

I

•

CT(pF) '" 12 ton (!'s)

•

R1

•

0.5V
RCl=-IPK

•

IPK + 10J
CF (/iF) '" ton (/is) =-V_O_ _ _
Vripple (PK)

BASIC CONFIGURATION
(lPK < 500 mAl

=

(VO - 1.2)

R1
TL497
R2 1.2 kO

EXTENDED POWER CONFIGURATION
(USING EXTERNAL TRANSISTOR)

FIGURE 1. POSITIVE REGULATOR, STEP-UP CONFIGURATIONS

2-138

t~~j

•
R1

TEXAS

.If

INSTRUMENTS
POST OFFiCe BOX 655012 • DALLAS, TEXAS 75265

kn

[~

=-

TL497 AM, TL497 AI, TL497 AC
SWITCHING VOLTAGE REGULATORS
TYPICAL APPLICATION DATA
RCL

T

T

I

r

14

13

10

B

DESIGN EQUATIONS

Vo
•

IPK ~ 2 10 max

R1

-

TL497

1

2

I

I

4

5

*cTI

I

3

7

6

;::[:;1

R2 1.2 kO

Choose L (50 to 500 /1Hl. calculate
ton (10 to 150 /1s)

BASIC CONFIGURATION
IpK < 500 mAl

•

CT(pF) "" 12 t on (/1s)

•

R1 ~ (Vo - 1.2) k[.l

•

v
I

L

RCL

I
14

I~_

0.5V

...

RCL ~-IpK

..c:

In
Q)
Q)

Vo

T

T

13

10

[~IPK+ 10J

R1

B

Vripple (PK)
TL497

1

2

I

I

3

.-----<

4

5

*CTI

I

6

7

en

...
ctI
ctI

C

;::F"

R2 1.2 kO

EXTENOEO POWER CONFIGURATION
(USING EXTERNAL TRANSISTOR I

FIGURE 2. POSITIVE REGULATOR, STEP-DOWN CONFIGURATIONS

TEXAS •
INSTRUMENTS
POST OFFICE BOX 655012 • DALLAS, TEXAS 75265

2-139

TL497 AM, TL497 AI, TL497 AC
SWITCHING VOLTAGE REGULATORS
TYPICAL APPLICATION DATA
RCL

L

r 1

14

13

10

8

2

3

4

I I

f1

CTI

I

•

,-------'

R1 1.2 kll

5

Choose L (50 to 500 JIH), calculate
ton (25 to 150 JIs)

Vo

8ASIC CONFIGURATION
(lPK < 500 mAl
RCL

•

CT(pF)

•

R2=(VO-1.2)kQ

•

0.5V
RCL=IPK

~

13

10

2

3

I If
I

4

8

12 ton(JIs)

5

+

R2

*

TL497

,-------'

rCF

*Use external catch-diode, e.g., 1 N4001, when building an
inverting supply with the TL497A.

R1 1.2 kll
Vo

CTI

1

EXTENDED POWER CONFIGURATION
(USING EXTERNAL TRANSISTORI

FIGURE 3. INVERTING APPLICATIONS

2-140

Re

L

r 1 .I¥I

1

IVai]
= 2 10 max [ 1 + \i'I

CF

-

14

IpK

R2

*

TL497

1

-t +

f

TEXAS ~

IN STRUM ENlS
POST OFFICE BOX 656012 • DALLAS, TEXAS 75265

TL497 AM, TL497 AI, TL497 AC
SWITCHING VOLTAGE REGULATORS

TYPICAL APPLICATION DATA
VI _ __<>----------SWITCHING----VO
CIRCUIT

I
CONTROL

II

TL497

5

EXTENDED INPUT CONFIGURATION WITHOUT CURRENT LIMIT
RCL
_-.-_ _ _---"NIr_--------SWITCHING-- VO
CIRCUIT

DESIGN EOUATIONS
VBE(Q1)

RCL=---llimit (PK)

r-~--~~--~omA

VI

R1=--

,.----I'-.

IB(02)

CONTROL

R2= (V reg -1) 10 kn

TL497

5

CURRENT LIMIT FOR EXTENOED INPUT CONFIGURATION

FIGURE 4. EXTENDED INPUT VOLTAGE RANGE (VI> 15 V)

TEXAS

~

INSTRUMENTS
POST OFFICE BOX 655012 • DALLAS, TEXAS 75265

2-141

•

C

I»
r+
I»

t/)

:::r
CD
CD

r+

til

2·142

TL5941, TL594C, TL595C
PULSE-WIDTH-MODULATION CONTROL CIRCUITS
02712, APRIL 1983-REVISEO OCTOBER 1988

TL5941. TL594C .. , D. J. OR N PACKAGE
(TOP VIEWI

• Complete PWM Power Control Circuitry
• Uncommitted Outputs for 200-mA Sink or
Source Current

ERROR jNONINV INPUT
AMP 1
INV INPUT
FEEDBACK
DEAD-TIME CONTROL
CT
RT
GND
C1 '-i..:_--'-''-'

1

• Output Control Selects Single-Ended or
Push-Pull Operation
• Internal Circuitry Prohibits Double Pulse at
Either Output
• Variable Dead-Time Provides Control Over
Total Range

NONINV INPUTl ERROR
INV INPUT
AMP 2
REF OUT
OUTPUT CONTROL
VCC
C2
E2

E1

TL595C ..• N
DUAL-IN-LINE PACKAGE
(TOP VIEW)

• Internal Regulator Provides a Stable 5-V
Reference Supply Trimmed to 1%
• Circuit Architecture allows Easy
Synchronization

ERROR jNONINV INPUT
AMP 1
INV INPUT
FEEDBACK
DEAD-TIME CONTROL
CT
RT
GND
C1

NONINV INPUTl ERROR
INV INPUT
AMP 2
REF OUT
Vz
OUTPUT CONTROL
STEERING INPUT
VCC

1

• Under-Voltage Lockout for Low VCC
Conditions
• TL595 has On-Chip 39-V Zener and External
Control of Output Steering

•
...
In
Q)
Q)

J:

en

...
ctI
ctI

C

C2

E1 '-l::_"":'::'I-'E2

description
The TL594 and TL595 devices each incorporates
on a single monolithic chip all the functions
required in the construction of a pulse-widthmodulation control circuit Designed primarily for
power supply control, these devices offer the
systems engineer the flexibility to tailor the power
supply control circuitry to his application,
The TL594 contains two error amplifiers, an onchip adjustable oscillator, a dead-time control
comparator, pulse-steering control flip-flop, 5-V
regulator with a precision of 1%, an undervoltage lockout control circuit, and output control
circuitry,

FUNCTION TABLE
INPUTS
STEERING
OUTPUT
CONTROL

OUTPUT FUNCTION

INPUT
(TL595 ONLY)

VI" 0

Open

VI" Vrel
VI" Vrel

Open
VI < 0

VI" Vrel

VI" Vrel

I

Single-ended or parallel output
Normal push-pull operation
PWM Output at 01
PWM Output at 02

The error amplifiers exhibit a common-mode
voltage range from -0,3 V to VCC -2 V. The
dead-time control comparator has a fixed offset
that provides approximately 5% dead time when
externally altered. The on-chip oscillator may be
bypassed by terminating RT (pin 6) to the
reference output and providing a sawtooth input
to CT (pin 5), or it may be used to drive the
common circuitry in synchronous multiple-rail
power supplies.
The uncommitted output transistors provide
either common-emitter or emitter-follower output
capability, Each device provides for push-pull or
single-ended output operation with selection by

Copyright

PRODUCTION DATA documents contain information

current as of publication date. Products conform to

specifications per the terms of Texas Instruments

~~~~~:~~i~ai~:1~1e ~!:~~~ti:fn ~Io::~:~:t:~~s not

TEXAS . "

INSTRUMENTS
POST OFFICE BOX 655012 • DALLAS, TEXAS 75265

©

1983, Texas Instruments Incorporated

2-143

TL5941, TL594C, TL595C
PULSE-WIDTH-MODULATION CONTROL CIRCUITS
description (continued)
means of the output·control function. The architecture of these devices prohibits the possibility of either
output being pulsed twice during push·pull operation. The undervoltage lockout control circuit locks the
outputs off until the internal circuitry is operational.
The TL595 provides the identical functions found in the TL594. In addition, the TL595 also contains an on·chip
39·V zener diode for high·voltage applications where Vee is greater than 40 V, and an output steering control
that overrides the internal control of the pulse·steering flip·flop.

•

The TL5941 is characterized for operation from - 25°C to 85°C. The TL594e and TL595e are characterized for
operation from ooe to 70°C .

functional block diagram

f- ;;~E;;;N-;; ;;;;P~

C

-

....

Dl
Dl
t/)

::r

I

L________ JI

RT----r----,

..J

C T - - " ' t ' - t_ _ _

C,

CD
CD

....
(II

,

TL595 ONL V
I OUTPUT CONTROL
I (SEE FUNCTION TABLE I I (SEE FUNCTION TABLEI

10
E1

DEAD ~ 0.1 V
TIME

C,

---l.-.--,_,

C2

CONTROL

PULSE-STEERING
FLIP-FLOP

-l

NON\~~~~TING _ _ _

INY::J~NG--_-cI
NON\~~~~TING - - - - f + '
INY~;J~NG - - - - q
TL594 AND TL595
FEEDBACK-------~~

2·144

r-------,

I
I

I
I

I
I

E2

VCC

I

Ir-~~

I
I

IL.--r-~

I

' - - - - - - - - - - - - R E F OUT

}-r~~~~-,~-~---------------GND

TEXAS ."

INSTRUMENTS
POST OFFICE BOX 655012 • DALLAS, TEXAS 75265

TL5941, TL594C, TL595C
PULSE-WIDTH-MODULATION CONTROL CIRCUITS
absolute maximum ratings over operating free-air temperature range (unless otherwise noted)
Tl594C

TL5941

Supply voltage, VCC (see Note 1)
Amplifier input voltages
Collector output voltage
Collector output current

UNIT

Tl595C

41

41

V

VCC+0.3
41

VCC+0.3
41

V
V

250

Operating free-air temperature range

mA
250
See Dissipation Rating Table
·C
-25 to 85
Oto 70

Storage temperature range

-65 to 150

-65 to 150

300
260

300
260

Continuous total dissipation

Lead temperature 1,6 mm (1/16 inch) from case for 60 seconds: J package
Lead temperature 1,6 mm (1/16 inch) from case for 10 seconds: D or N package

'c
'c
'c

fI)

CD
CD

DISSIPATION RATING TABLE

= 70·C

= 8S·C

TA:S; 2S'C

DERATING

DERATE

POWER RATING

FACTOR

ABOVETA

POWER RATING

POWER RATING

7_6mW/'C

25'C
28·C

608mW

494mW

J

950mW
1000 mW

656mW

533mW

N

1000mW

41'C

736mW

598mW

PACKAGE

D

8.2mWrC
9.2mWrC

•
...

NOTE 1: All voltage values, except differential voltages, are with respect to the network ground terminal.

TA

TA

~

CI)

...caca

C

recommended operating conditions
Tl594C
Tl595C

Tl5941
M!N

Supply voltage, VCC
Amplifier input voltages, VI

MAX

MIN

7

40

7

-0.3

VCC-2

-0.3

Collector output voltage, Vo
Collector output current (each transistor)
Current into feedback terminal
0.47

Oscillator frequency

1
-25

1.8

Operating free-air temperature, TA

TEXAS ."

INSTRUMENTS
POST OFFICE BOX 655012 • DALLAS, TEXAS 75265

40
VCC- 2

V
V

40

40

V

200

200

mA

0.3

mA
nF

0.3

Timing capacitor, CT
Timing resistor, RT

UNIT

MAX

10000
500

0.47
1.8

10000
500

300

1

300

85

0

70

k!l.

kHz
·C

2-145

TL5941, TL594C, TL595C
PULSE-WIDTH-MODULATION CONTROL CIRCUITS
electrical characteristics over recommended operating free-air temperature range,
(unless otherwise noted)

Vee =

15

reference section
PARAMETER
Output voltage (Vref)
Input regulation
Output regulation
Output voltage change
with temperature
Short-circuit output current§

TEST CONDITIONSt

MIN

TYP*

MAX

UNIT

TA - 25'C
TA - 25'C

4.95

5
2

5.05
25

V
mV
mV

10-1 mA,
VCC - 7 V to 40 V,
10 - 1 to 10 mA,

14

35

0.2%

1%

10

35

50

MIN

TYP*
10

MAX

TA = 25'C

ATA = MIN to MAX
Vref = 0

mA

oscillator section (see Figure 2)

C
m
r+
m

Frequency

en

Standard deviation of frequency'

All values of VCC, CT, RT, TA constant

Frequency change with voltage

VCC = 7Vt040V,
ATA - MIN to MAX

::r

(1)
(1)

Cil'

PARAMETER

Frequency change with temperature

TEST CONDITIONSt

TA

UNIT
kHz

10%

=25'C

0.1%
12%

amplifier sections (see Figure 1)
PARAMETER

TEST CONDITIONS

MIN

UNIT

TYP*
2

MAX

Feedback control at 2.5 V

25

250

nA

Input bias current

Feedback control at 2.5 V

0.2

1

J,lA

Common-mode input voltage range, error
amplifier

VCC = 7 V to 40 V

Open-loop voltage amplification, error
amplifier

AVO=3V,
RL = 2 kO

Vo = 0.5 V to 3.5 V

Unity-gain bandwidth

Vo = 0.5 Vto 3.5 V,

RL - 2 kO

Input offset voltage, error amplifier

Feedback pin at 2.5 V

Input offset current

10

mV

-0.3

Common-mode rejection ratio, error amplifier Vec = 40V,
Output sink current (pin 3)
VID - -15mVto
Output cource current (pin 3)

to

V

Vee- 2

5V,

VID-15mVt05V,

TA = 25'e
Feedback control at 0.5 V
Feedback at 3.5 V

70

95

dB
kHz

65

800
80
0.7

mA

0.3
-2

rnA

t For conditions shown as MIN or MAX, use the appropriate value specified under recommended operating conditions.
All typical values except for parameter changes with temperature are at TA = 25'e.
§ Duration of the short-circuit should not exceed one second.
, Standard deviation is a measure of the statistical distribution about the mean as derived from the formula

*

(1=

2-146

TEXAS . "

INSTRUMENTS
POST OFFICE BOX 656012 • DALLAS, TeXAS 75265

dB

V

TL5941, TL594C, TL595C
PULSE·WIDTH·MODULATION CONTROL CIRCUITS
electrical characteristics over recommended operating free-air temperature range,
(unless otherwise noted)

Vee = 15 V

dead-time control section (see Figure 2)
PARAMETER

TEST CONDITIONS

Input bias current (pin 4)

VI - Oto 5.25 V
Dead-time control at 0 V

Maximum duty cycle. each output

MIN

TYpt

MAX

2

10

3

3.3

TYpt

MAX

2

100

IlA

45%

Zero duty cycle

Input threshold voltage (pin 4)

UNIT

0

Maximum duty cycle

V

output section
TEST CONDITIONS
VCE - 40V.

VCC - 40V

= 15 V.
VCC = 1 t03 V.

VE

Vc

Collector off-state current

MIN

= OV.
4

200

UNIT

II)

IlA

= Vc = 40 V.
= O.

VCC

Collector-emitter

I Common-emitter

saturation voltage

I Emitter-follower

Output control input current

VE
Vc - 15 V.

VE = 0
IC = 200 mA
IE - -200 mA

-100

1.1
1.5

1.3
2.5
3.5

VI- Vref

II)
II)

..c:

Dead-time and output control pins at 0 V
Emitter off-state current

II
....

IlA
V

rnA

Ul

....caca
o

pwm comparator section (see Figure 2)
TEST CONDITIONS

PARAMETER
Input threshold voltage (pin 3)

Zero duty cycle

Input sink current (pin 3)

V(pin 3) - 0.5 V

MIN
0.3

TYpt

MAX

4

4.5

0.7

under-voltage lockout section (see Figure 2)
PARAMETER

TEST CONDITION*
TA = 25"C
~

TERMINAL

tn
::r
CD

....CDtil
vrer-----I
AMPLIFIER

FIGURE 1. AMPLIFIER CHARACTERISTICS

2-148

TEXAS •

INSTRUMENTS
POST OFFICE BOX 655012 • DALLAS, TEXAS 75265

UNIT

ns
ns

TL5941, TL594C, TL595C
PULSE-WIDTH-MODULATION CONTROL CIRCUITS
PARAMETER MEASUREMENT INFORMATION
VCC=15V

150n 150n
2W
2W
VCC

- - - - I DEAD-TIME

C1
E1

TEST {
INPUTS

C2 .....- - - OUTPUT 2

......-4f--ICT

(_)

r-t-.....-I(+)

•

-=

--:-:12""'k""'"n:---I FEEDBACK
RT

(+}

OUTPUT 1

1-+_ _-,

E2
STEERING
CONTROL
AMPLIFIERS
Vz

...en

(OPENll TL595

Q)
Q)

(OPEN)f ONLY

(-)

50 kn

J:

o

REF
OUTPUT

OUTPUT
CONTROL

...
ctI
ctI

GND

C
TEST CIRCUIT
-----VCC
VOLTAGE
AT C1

- - --0
-----VCC
VOLTAGE
ATC2

VOLTAGE
ATCT

DEAD-TIME
CONTROL
INPUT
OV

FEEDBACK

0.7 V--------....,II-----jl~.:---.-:-I-:-:-MAX
DUTY
CYCLE

I
I
I
I

1--0%--

O%--t---l
VOLTAGE WAVEFORMS

FIGURE 2. OPERATIONAL TEST CIRCUIT AND WAVEFORMS

TEXAS ."

INSTRUMENTS
POST OFFICE BOX 655012 • DALLAS, TEXAS 75265

2-149

TL5941, TL594C, TL595C
PULSE-WIDTH-MODULATION CONTROL CIRCUITS
PARAMETER MEASUREMENT INFORMATION
15 V

(\EACH OUTPUT-j
ICIRCUIT)

II
I

68 Il,
2W

.;---1~"''''-OUTPUT
----11--.

CL - 15 pF
(includes probe and
jig capacitance)

IL _____ .JI

OUTPUT VOLTAGE WAVEFORM

TEST CIRCUIT

FIGURE 3. COMMON-EMITTER CONFIGURATION

15V

I(EACHOUTPUT - ,
ICIRCUIT)

I
I
I

- ___I--'f---.-OUTPUT

L_____ J

68 Il,
2W

CL - 15 pF
(Includes probe and
jig capacitance)

OUTPUT VOLTAGE WAVEFORM

TEST CIRCUIT

FIGURE 4, EMITTER-FOLLOWER CONFIGURATION

2-150

TEXAS

+

INSlRUMENTS

POST OFFICE BOX 655012 • DALLAS, TEXAS 75265

TL5941, TL594C, TL595C
PULSE-WIDTH-MODULATION CONTROL CIRCUITS
TYPICAL CHARACTERISTICS
OSCILLATOR FREQUENCY and
FREQUENCY VARIATIONt vs
TIMING RESISTANCE

AMPLIFIER VOLTAGE AMPLIFICATION
vs
FREQUENCY
100

90


...en

"\.
'\.

o
1

10

RT- Timing Resistance-I)

FIGURE 5

100
1 k
10 k
f-Frequencv-Hz

100 k

...caca

C

1 M

FIGURE 6

t Frequency variation (At) is the change in oscillator frequency that occurs over the full temperature range.

TEXAS ",

INSTRUMENTS
POST OFFICE BOX 655012 • CALLAS, TEXAS 75265

2-151

•

C

I»
r+
I»

en

:::r

(1)
(1)

r+
CII

2-152

TL598
PULSE-WIDTH-MODULATION CONTROL CIRCUIT
03026. FEBRUARY 1988-REVISEO OCTOBER 1988

•

Complete PWM Power Control Function

•

Totem-Pole Outputs for 200-mA Sink or
Source Current

•

Output Control Selects Parallel or Push-Pull
Operation

•

Internal Circuitry Prohibits Double Pulse at
Either Output

•

Variable Dead-Time Provides Control Over
Total Range

•

Internal Regulator Provides a Stable 5-V
Reference Supply. Trimmed to 1%
Tolerance

•

On-Board Output Current-Limiting Protection

•

Under-Voltage Lockout for Low VCC
Conditions

•

Independent p'0wer and Signal Grounds

•

D. J. DR N PACKAGE
(TDP VIEWI
ERROR jNONINV INPUT
AMP 1
INV INPUT
FEEDBACK
DEAD·TIME CONTROL

I

CT
RT
SIGNAL GND

3
4

NONINV INPUT} ERROR
INV INPUT
AMP 2
REF OUT
OUTPUT CONTROL
VCC

Vc
POWER GND

OUT1 ........_ - - '.... OUT2

II
...

FUNCTION TABLE
INPUT
OUTPUT
CDNTRDL
V,
V,

= GND
= Vref

en

DUTPUT FUNCTION

CD
CD

Single-ended or parallel output

.c

en
as
as

Normal push-pull operation

...

C

TL59SQ Has Extended Temperature
Range ... -40°C to 125°C

description
The TL598 incorporates all the functions required in the construction of pulse-width-modulated controlled
systems on a single monolithic chip. Designed primarily for power supply control. the TL598 provides the
systems engineer with the flexibility to tailor the power supply control circuits to a specific application.
The TL598 contains two error amplifiers. an internal oscillator (externally adjustable). a dead-time control
comparator. a pulse-steering flip-flop. a 5-V precision reference. an under-voltage lockout control. and output
control circuits. Two totem-pole outputs provide exceptional rise and fall time performance for power FET
control. The outputs are designed with the collectors sharing a common source supply and common power
grounds and are independent of Vec and signal ground.
The error amplifier has a common-mode voltage range from -0.3 V to VCC - 2 V. The dead-time control
comparator has a fixed offset that prevents overlap of the outputs during push-pull operation. Synchronous
mUltiple supply operation may be achieved by connecting pin 6 to the reference output and providing a
sawtooth input to pin 5.
The TL598 device provides an output control function to select either push-pull or parallel operation. Circuit
architecture prevents either output from being pulsed twice during push-pull operation.
The TL598Q is characterized for operation from -40°C to 125°C. The TL598C is characterized for
operation from ooC to 70°C.

PRODUCTION DATA documents .ontain informltion
clllr".t I' of publication data. Predicts conform to
spacifications par the tarllli 0' Tax•• Instruments

=~~ir,8i:l:ri ~::':~ti:; l!r:::::~:~ not

~

TEXAS
INSTRUMENTS
POST OFFICE BOX 655012 • DALLAS, TEXAS 75265

Copyright @ 1988, Texas Instruments Incorporated

2-153

TL598
PULSE·WIDTH·MODULATION CONTROL CIRCUIT
logic diagram (positive logic)
OUTPUT CONTROL
(SEE FUNCTION TABLE)

RT

Vc

CT

DEAD- ~ 0.1 V
TIME ---t
CONTROL

OUT1
C1

NONINVERTING
INPUT

C

C»
r+
C»

en
J

INVERTING
INPUT
NON INVERTING
INPUT
INVERTING
INPUT
FEEDBACK

OUT2
POWER
GND
r---------------------------~------------------VCC

CD
CD
r+
In

~-------------------------------------REFOUT

~---------------------------------------------- SIGNAL

GND

2-154

TEXAS •

INSTRUMENTS
POST OFFICE BOX 655012 • DALLAS, TEXAS 75265

TL598
PULSE-WIDTH-MODULATION CONTROL CIRCUIT
absolute maximum ratings over operating free-air temperature range (unless otherwise noted)
Supply voltage, VCC (see Note 1) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 41 V
Amplifier input voltage, VI .............................................. VCC +0.3 V
Collector voltage. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 41 V
Output current (each output). sink or source, 10 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 250 mA
Continuous total dissipation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. See Dissipation Rating Table
Operating virtual junction temperature range, TJ: TL598Q .................. -40·C to 150°C
TL598C .................... O·Cto 150°C
Storage temperature range ......................................... - 65·C to 150°C
Lead temperature 1,6 mm (1/16 inch) from case for 60 seconds: J package ............ 300°C
Lead temperature 1,6 mm (1/16 inch) from case for 10 seconds: D or N package ........ 260°C
NOTE 1: All voltage values, except differential voltages, are with respect to the network ground terminal.

en

DISSIPATION RATING TABLE

PACKAGE

POWER

DERATING

ABOVE

RATING

FACTOR

TA

PI
...

TA - 70·C
POWER

TA - 125·C
POWER

RATING

RATING

D

950 mW

7.6 mW/·C

25·C

60S mW

190mW

N

1200 mW

13 mW/·C

5S·C

1040 mW

325 mW

Q)
Q)

.c

rn

...

CO
CO

C

recommended operating conditions
Supply voltage, VCC
Amplifier input voltage, VI

MIN

MAX

7

40

-0.3

VCC- 2
40

Collector voltage

UNIT
V
V
V

Output current (each output), sink or source, 10

200

mA

Current into feedback terminal, IlL

0.3

mA

0.00047

10

~F

500

kG

300

kHz

TL59SQ

1.8
1
-40

TL59SC

0

70

Timing capacitor, CT
Timing resistor, RT

Oscillator frequency, fosc

I
I

Free-air temperature, T A

TEXAS ~

INSTRUMENTS
POST OFFICE BOX 655012 • DALLAS, TeXAS 75265

125

·C

2-155

TL598
PULSE·WIDTH·MODULATION CONTROL CIRCUIT

electrical characteristics over recommended operating free-air temperature range.
f =- 10 kHz (unless otherwise noted). see Note 2

Vee

15 V.

reference section
TEST CONDITIONSt

PARAMETER

E

10

Input regulation

Vee

Output regulation

10

Output voltage change

with temperature

C

Short-circuit output current§

1 rnA.

4.95
TA - 25°e
TA = MIN to MAX 4.9

=

TA

=

Output voltage (V ref)

=

7 V to 40 V.

~TA

= MIN to

Vref

=0

I»

at

oscillator section (see Figure 1) CT

en
:r

TA
TA

1 to 10 rnA.

=
=
=

TL598Q
TYpt MAX

MIN

6

25°e

2

25°e
MIN to MAX

1

MAX

-35

r+

0.2

1

2

-10

-35

TEST eONDITIONSt

MIN

Typt

V
mV
mV
%

rnA

MAX

Standard deviation of frequency'

All values of Vee. eT. RT. TA constant

Frequency change with voltage

Vee

Frequency change with temperature #

~TA

= 7Vt040V.TA =
= MIN to MAX

10

25°e

UNIT
kHz

100

Frequency

(II

1

5.05
5.1
25
15

5

UNIT

,.F. RT - 12 kO

PARAMETER

CD
CD

TL598C
Typt
MAX

4.9

1

0.2
-10

= 0.001

5.05
5.1
22
15
80

MIN
4.95

%

0.1

1

%

2

5

%

TYpt

MAX

2
25
0.2

10

error amplifier section
PARAMETER
Input offset voltage
Input offset current

Feedback pin at 2.5 V
Feedback pin at 2.5 V

Input bias current

Feedback pin at 2.5 V

Common-mode input

voltage range
Open-loop voltage
amplification
Unity-gain bandwidth
Common-mode
rejection ratio

TEST eONDITIONS

MIN

250
1

UNIT
mV
nA
~A

-0.3
Vee

=7

to

V to 40 V

V

VCC- 2
~VO

Vee

(pin 3)

=3

V.

= 40 V.

Vo (pin 3)

~Vle

Output sink current (pin 3)

Feedback pin at 0.5 V

Output source current (pin 3)
Phase margin at unity gain

Feedback pin at 3.5 V
Feedback pin

Supply voltage rejection ratio

Feedback pin at 2.5 V.

= 0.5 V

to 3.5 V. RL

=

~Vee

= 0.5

= 36.5

V to 3.5 V

V. TA

=

25°e

2 k!l

= 33

V.

RL

=

2 k!l

70

95

dB

800

kHz

65

80

dB

0.3
-2

0.7

mA
rnA

65°
100

dB

t For conditions shown as MIN or MAX, use the appropriate value specified under recommended operating conditions. r-::
N, - - - t All typical values except for parameter changes with temperature are at T A = 25°e.
2
§ Duration of the short-circuit should not exceed one second.
t (xn - X)
'Standard deviation is a measure of the statistical distribution about the mean as derived from the formula
n- 1
N-1
#Effects of temperature on external RT and CT are not taken into account.
NOTE 2: Pulse testing techniques must be used that will maintain the junction temperature as close to the ambient temperature as possible.

2-156

TEXAS ~

INSTRUMENTS
POST OFFICE BOX 655012 • DALLAS, TEXAS 75265

TL598
PULSE-WIDTH-MODULATION CONTROL CIRCUIT

electrical characteristics over recommended operating free-air temperature range, Vee = 15 V,
f - 10 kHz (unless otherwise noted), see Note 2
under-voltage lockout section
TL598Q

TEST CONDITIONSt

PARAMETER

TA = 25°C

Threshold voltage

Hysteresis t

TL598C

MIN

MAX

MIN

MAX

4

6
6.9

4

6
6.9

ATA = MIN to MAX

3.8

TA = 25°C

100

100

30

50

TA = MIN to MAX

3

UNIT
V
mV

output section
PARAMETER

TEST CONDITIONS

MIN

VCE = 40 V,

Vee = 40 V,
Dead-time pin is connected to REF

Collector off-state current
High-level output voltage

lOW-level output voltage

Vee = 15 V,

10 = -200 mA

12

Ve=15V,

10 -

13

Vee = 15 V,

10 = 200 mA

Ve = 15 V,

10 = 20 rnA

-20 mA

TVP§

MAX

2

100

2

0.4

VI = Vref
VI = 0.4 V

Output control input current

p.A

...

V

.c

UNIT

U)

Q)
Q)

CI)

...
CO
CO

V

3.5

mA

100

p.A

C

dead-time control section (see Figure 1)
PARAMETER

TEST CONDITIONS

MIN

Input bias current (pin 4)

VI = 0 to 5.25 V

Maximum duty cycle, each output

Dead-time control at 0 V

TL598Q
TVp9
MAX
-2

Input threshold voltage (pin 4)

TL598C
TVP§
MAX
-2

-10

3

3.3

45
3

Maximum duty cycla

-25

45

2ero duty cycle

MIN

0

3.2

UNIT
~A

%

0

V

pwm comparator section
PARAMETER

TEST CONDITIONS

Input threshold voltage (pin 3)

Zaro duty cycle

Input sink current (pin 3)

V in

3)

= 0.5 V

MIN
0.3

total device (see Figure 1)
PARAMETER
Standby supply current

I Vee
I Vee

and outputs open
Average supply current

TVP§

MAX

= 15 V

15

21

= 40 V

17

23

TEST CONDITIONS
Pin 6 at V ref,
All· other inputs

MIN

UNIT
mA

Dead-time control at 2 V

15

mA

tFor conditions shown as MIN or MAX. use the appropriate value specified under recommended operating conditions.
*Hysteresis is the difference between the positive-going input threshold voltage and the negative-going input threshold voltage.
§AII typical values except for parameter changes with temperature are at T A = 25°C
NOTE 2: Pulse testing techniques must be used that will maintain the junction temperature as close to the ambient temperature as possible.

switching characteristics, T A = 25 De
TEST CONDITIONS

PARAMETER
Output voltage rise time

eL = 1500 pF,

Output voltage fall time

Ve = 15V,

Vee = 15 V, See Figure 2

TEXAS •

INSTRUMENTS
POST OFFICE BOX 655012 • DALLAS. TEXAS 75265

MIN

TVP

MAX

100

150

50

75

2-157

TL598
PULSE·WIDTH·MODULATION CONTROL CIRCUIT
PARAMETER MEASUREMENT INFORMATION
r----

.,..-o-!-----....-

15 V

OUTPUT
Vc

VCC

•

~t

ERROR AMPLIFIERS

TEST {
INPUTS

50 kll
OUTPUT CONFIGURATION

DT CONTROL

C

15V

Vc

RT

en
::r

REF
OC

CT

DI
r+
DI

OUT1

OUTPUT 1

OUT2

OUTPUT 2

FEEDBACK

SIGNAL GND

CD
CD

POWER GND

r+
(I)

l~

FEEDBACK

';

"::"

MAIN DEVICE TEST CIRCUIT
ERROR AMPLIFIER TEST CIRCUIT

FIGURE 1. TEST CIRCUITS

...--0----- Vc
I

....

-c~--.-

I
I

OUTPUT

I
I
I

CL - 1500 pF

I

.,.. POWER GND

I

tr~

OUTPUT VOLTAGE WAVEFORM

OUTPUT CONFIGURATION

FIGURE 2. SWITCHING OUTPUT CONFIGURATION AND VOLTAGE WAVEFORM

2-158

TEXAS •

INSTRUMENTS
POST OFFICE BOX 655012 • DALLAS, TEXAS 75265

OV

TL750L, TL7SH SERIES
LOW·DROPOUT VOLTAGE REGULATORS
03017, SEPTEMBER 1987-REVISEO FEBRUARY 1988

•

Very Low Dropout Voltage, Less
than 0.6 V at 150 mA

•

Very Low Quiescent Current

•

TTL· and CMOS·Compatible Enable On
TL751L Series

•

60-V Load-Dump Protection

•

Reverse Transient Protection to - 50 V

•

Internal Thermal Overload Protection

•

Over-Voltage Protection

•

Internal Over-Current Limiting Circuitry

terminal assignments
TL750L ... D

TL750L ... KC

SMALL OUTLINE PACKAGE

HEAT-SINK-MOUNTED PACKAGE

TL750L ... LP
SILECT'" PACKAGE

(TOP VIEW)

(TOP VIEW)

DS
(TOP VIEW)

OUTPUT
COMMON

2

7

INPUT
COMMON

COMMON

3

6

COMMON

NC

4

5

NC

fI)

CD
CD

.c
UJ

...'"

THE COMMON TERMINAL IS IN
ELECTRICAL CONTACT WITH
THE MOUNTING BASE

'"

C
TO-226AA

TO-220AB

~'

•

PI
...

0'

I

TL750L. , . P

TL751L ... D

TL751L ... P

DUAL-IN-L1NE PACKAGE

SMALL OUTLINE PACKAGE

DUAL-IN-L1NE PACKAGE

(TOP VIEW)

(TOP VIEWI

(TOP VIEW)

OO~'D"M
NC
NC

2
3

7
6

NC
COMMON

NC

4

5

NC

•

OO~'D·'~

COMMON
COMMON

2
3

7
6

COMMON
COMMON

NC

4

5

ENABLE

NC-No internal connection
SILECT is a trademark of Texas Instruments Incorporated.

PRODUCTION DATA docum.nts OOlIIIIin infarmllio.
..rrant •• of publicotiD. dill. Products ..",orm to
.pICificotio.. par th.t..... of T.... Instrum.nts

=ir:t:l"::li =r::r :'r::'':~~~ not

•
TEXAS

O~D·M
NC

2

7

NC

3

6

NC

COMMON

NC

4

5

ENABLE

•
~

INSTRUMENTS
POST OFFICE BOX 655012 • DALLAS, TEXAS 75265

Copyright © 1987, Texas Instruments Incorporated

2-159

TL750L, TL751 L SERIES
LOW-DROPOUT VOLTAGE REGULATORS
description
The TL750L and TL751 L series are low-dropout positive voltage regulators specifically designed for batterypowered systems. The TL750L and the TL751L incorporate over-voltage and current-limiting protection
circuitry along with internal reverse-battery protection circuitry to protect both itself and the regulated
system. Both series are fully protected against 60-volt load-dump and reverse-battery conditions. Extremely
low quiescent current during full-load conditions makes the TL750L and TL751 L series ideal for standby
power systems.
The TL750L series of fixed-output voltage regulators offer 5-volt, a-volt, 10-volt, and 12-volt options.
They are available in TO-226AA (formerly TO-92) (LP) packages, TO-220AB (KC) packages, a-pin "small
outline" plastic packages (0), and a-pin plastic dual-in-line packages (P).

E

The TL 751 L series of fixed-output voltage regulators also offer 5-volt, a-volt, 10-volt, and 12-volt options
with the addition of an enable input. The enable input, when taken high, places the regulator output in
a high-impedance state. This gives the designer complete control over power up, power down, or emergency
shut down. This series is offered in the a-pin "small outline" plastic package and the a-pin plastic dual-inline package.

C
m
r+

m

en
:r-

absolute maximum ratings over operating junction temperature range (unless otherwise noted)

CD
CD

r+

(I)

TL750L

TL751L

UNIT

26

26

V

60
-15

V

Continuous reverse input voltage

60
-15

Transient reverse input voltage: t ::s: 100 ms

-50

-50

V

825
2000

825

Continuous total dissipation at lor below) 25°C free-air

D package
KC package

temperature (see Note 1):

LP package

775
1000

1000

Operating virtual junction temperature range

-40 to 150

-40 to 150

°C

Storage temperature range

-65 to 150

-65 to 150

°C

260

260

°C

Continuous input voltage

Transient input voltage, T A - 25°C (see Note 1)

P package

Lead temperature 1,6 mm (1/16 inch) for 10 seconds

V

mW

NOTES: 1. The transient input voltage rating applies for the waveform described in Figure 1.
2. For .operation above 25°C free-air temperature, linearly derate the D package at the rate of 6.6 mW/oC, the KC package at
15.2 mW/oC, the LP package at 6.2 mW/oC, and the P package at 8 mW/oC.

recommended operating conditions over recommended operating junction temperature range (unless
otherwise noted)

Input voltage, VI

26

9

26

11

26

TL75_L12

13

26

TL751L

Low-level ENAli[E voltage, VIL t

TL751L
TL75_L
TL75_L_C
TL75_L_Q

Operating virtual junction temperature, T J

MAX

6

TL75_Ll0

High-level ENABLE input voltage, VIH
Output current, 10

MIN
TL75 L05
TL75_L08

UNITS

V

2

15

-0.3

0.8

V

0

150

mA

0
-40

125
125

V

°C

tThe algebraic convention, in which the least positive (most negative) value is designated minimum, is used in this data sheet for ENAiiIT
voltage levels and temperature only.

2-160

TEXAS . "

INSTRUMENTS
POST OFFICE BOX 655012 • DALLAS. TEXAS 75265

TL750L. TL751L SERIES
LOW·DROPOUT VOLTAGE REGULATORS
TL 750L05 and TL 751 L05 electrical characteristics at 25°C virtual junction temperature. VI - 14 V.
10 = 10 mA (unless otherwise noted)
PARAMETER
Output voltage
Input regulation

TEST CONDITIONSt
VI = 6 V to 26 V,

I TJ

MIN
4.BO

10 = 0 to 150 mA

I

4.75

VI = 9 V to 16 V
VI = 6 V to 26 V
f=120Hz

Ripple rejection

VI = BVto lBV,

Output regulation

10 = 5mAto150mA

Dropout voltage
Output noise voltage
Bias current

= 25°C
TJ - TJ min to 125°C

60

TYP
5

MAX
5.2

5

5.25
10

6

30

65
20

10 = 10mA

10 = 150 mA
VI = 6 V to 26 V,

10 = 10mA,

TJ = TJ min to 125°C

V
mV
dB

50
0.2
0.6

10 = 150 mA
f = 10 Hz to 100 kHz

UNIT

500
10

12

1

2

mV

PI
...

V
/loV
mA

(I)

TL750LOS and TL 751 LOS electrical characteristics at 25°C virtual junction temperature. VI - 14 V •
10 = 10 mA (unless otherwise noted)
TEST CONDITIONSt

PARAMETER
Output voltage
Input regulation

I TJ
I TJ

VI = 9 V to 26 V,
10 = 0 to 150 mA
VI = 9 V to 26 V
VI=IIVto21V,

Output regulation

10 = 5 mA to 150 mA

Output noise voltage
Bias current

f = 120 Hz

TYP
B

7.6

VI = 10 V to 17 V

Ripple rejection

Dropout voltage

= 25°C
= TJ min to 125°C

MIN
7.B

60

MAX
B.2
B.4

10

20

25

50

65
40

10 - 10 mA
500

10 = 150mA
VI = 9 V to 26 V,

10 = 10 mA,

TJ = TJ min to 125°C

UJ

...asas

UNIT
V

C

mV
dB

BO
0.2
0.6

10= 150mA
f = 10 Hz to 100 kHz

Q)
Q)

.c

mV
V
/loV

10

12

1

2

mA

TL750L 10 and TL751 L 10 electrical characteristics at 25°C virtual junction temperature. VI - 14 V.
10 = 10 mA (unless otherwise noted)
TEST CONDITIONst

PARAMETER
Output voltage
Input regulation

VI = 11 V to 26 V,
10 = 0 to 150 mA

MIN

I TJ

I

= 25°C
TJ = TJ min to 125°C

Ripple rejection
Output regulation

10 = 5 mA to 150 mA

Dropout voltage

10 = 10mA
10 = 150 mA

Output noise voltage

f - 10 Hz to 100 kHz

Bias current

10= 150mA
VI = 11 V to 26 V,

f-120Hz

MAX

10 10.25

9.50

10.50

VI = 12Vto 19V
VI - 11 V to 26 V
VI - 12 V to 22 V,

TYP

9.75

60

25
60

mV

65
50

100

mV

dB

0.6

TJ = TJ min 125°C

V

10
30

0.2

10 = 10 mA,

UNIT

700
10

12

1

2

V
/loV
mA

tPulse testing techniques are used to maintain the junction temperature as close to the ambient temperature as possible. Thermal effects
must be taken into account separately. All characteristics are measured with a O.1-"F capacitor across the input and a 10-I'F capacitor,
with equivalent series resistance of less than 1 ohm, across the output.

TEXAS

~

INSTRUMENTS
POST OFFICE BOX 655012 • DALLAS, TEXAS 75265

2·161

TL750L, TL751L SERIES
LOW·DROPOUT VOLTAGE REGULATORS
TL750L 12 and TL751L 12 electrical characteristics at 25°C virtual junction temperature, VI - 14 V,
10 ... 10 mA (unless otherwise noted)
TEST CONDITIONst

PARAMETER
Output voltage

E
c

a
m

I TJ =

VI = 13 V to 26 V,

I

10 = 0 to 150 mA

Input regulation

VI = 14 V to 19 V
VI = 13Vto26V

Ripple rejection

VI-13Vto23V,

Output regulation

10 = 5 mAto 150 mA

Dropout voltage

10 = 10 mA
10= 150mA

Output noise voltage

f - 10 Hz to 100 kHz

Bias current

10 - 150 rnA
VI = 13Vto26V,

25°C
TJ = TJ min to 125°C

MIN

TYP

11.7

12

11.4

12.6
15

f - 120 Hz

50

MAX
12.3

20
55
50

mV

120

mV

dB

0.6

10 = lOrnA,

TJ = TJ min to 125°C

1

V

30
40

0.2
700
10

UNIT

V
p.V

12
2

mA

tPulse testing techniques are used to maintain the junction temperature as close to the ambient temperature as possible. Thermal effects

o
:::r

must be taken into account separately. All characteristics are measured with a O.1-",F capacitor across the input and a 10-I'F capacitor.

Cil'

ABSOLUTE MAXIMUM RATINGS

with equivalent series resistance of less than 1 ohm. across the output.

CD
CD

TRANSIENT INPUT VOLTAGE
vs
TIME
60

>

50

i>

40

Co

30

....

~

\

I

..'"

oS
VI

c
I!
lI

'"

OIl

:"...

~
tr - 1, ms

...........

C

.!!

I\.

20

~ .........

TA - 250C'
;;- 10 r-VI _ 14 V + 46e (-t/0.230)
for t ;;, 5 ms

o

o

I
100

I

I

I

200
300
400
t-Time-ms

-500

FIGURE 1

2·162

TEXAS . "

INSTRUMENTS
POST OFFICE BOX 655012 • DALLAS, TEXAS 75265

600

TL750M, TL751M SERIES
LOW-DROPOUT VOLTAGE REGULATORS
03017. JANUARY 1988-REVISED OCT08ER 1988

•

Very Low Dropout Voltage. Less than O.S V
at 750 rnA

3-LEAD KC (TD-220ABI PACKAGE

•

Low Quiescent Current

•

TTL- and CMOS-Compatible Enable on
TL751M Series

o
COMMON
~
INPUT

•

SO-V Load-Dump Protection

(TOPVIEWI

OUTPUT

THE COMMON TERMINAL IS IN
ELECTRICAL CONTACT WITH

•

Over-Voltage Protection

•

Internal Thermal Overload Protection

•

Internal Over-Current Limiting Circuitry

THE MOUNTING BASE

•
....enCD

description
The TL750M and TL751 M series are lowdropout positive voltage regulators specifically
designed for battery-powered systems. The
TL750M and TL751 M incorporate on-board
over-voltage and current-limit protection circuitry
to protect both themselves and the regulated
system. Both series are fully protected against
60-V load-dump and reverse battery conditions.
Extremely low quiescent current. even during
full-load conditions. makes the TL750M and
TL751 M series ideal for standby power systems.

CD

.r:.

en

....C'C'CCII

5-LEAD KC PACKAGE

C

(TOP VIEW)

O
o

The TL750M series of fixed-output voltage
regulators offer 5-V. a-v, 10-V. and 12-V
options available in 3-lead KC (TO-220AB)
plastic packages.

NC
OUTPUT
COMMON
INPUT
ENABLE

GROUND TERMINAL IS IN
ELECTRICAL CONTACT WITH
MOUNTING BASE

The TL 751 M series of fixed-output voltage
regulators also offer 5-V. a-v. 10-V, and 12-V
options with the addition of an enable input. The
enable input gives the designer complete control
over power-up. allowing for sequential powerup or emergency shutdown. When taken high,
the enable input places the regulator output in
a high-impedance state. It is completely TTL- and
CMOS-compatible. The TL751 M series is
offered in 5-lead KC plastic packages.
The TL750M and TL751 M series are
characterized for operation from - 40°C
to 125°C free-air temperature.

PRODUCTION DATA do.umonts ..ntoin in'Drmllion

current

I' of publication date. Products confarm ta

spacifications par the terms of Taxas Instruments
i :,~O::::A::~I
==ri~'ir~:I:ri

=3:: :r

not

TEXAS

~

INSTRUMENTS
POST OFFICE BOX 656012 • DALLAS. TeXAS 75265

Copyright © 1988, Texas Instruments Incorporated

2-163

TL750M, TL751M SERIES
LOW·DROPOUT VOLTAGE REGULATORS
absolute maximum ratings over operating free·air temperature range (unless otherwise noted)
Continuous input voltage. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 26 V
Transient input voltage (see Figure 1) ........................................... 60 V
Continuous reverse input voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. - 1 5 V
Transient reverse input voltage: t = 100 ms .................................... - 50 V
Continuous total dissipation at (or below) 25°C free-air temperature (see Note 1) . . . . . . . . . .. 2 W
Continuous total dissipation at (or below) 25°C case temperature (see Note 1) . . . . . . . . . . .. 20 W
Operating free-air, case, or virtual junction temperature. . . . . . . . . . . . . . . . . . .. -40°C to 150°C
Storage temperature range ......................................... - 65°C to 150°C
Lead temperature 1,6 mm (1/16 inch) from case for 10 seconds. . . . . . . . . . . . . . . . . . . . .. 260°C

c
....
I\)

I\)

Note 1: For operation above 25°C free-air temperature, refer to Figures 2 and 3. To avoid exceeding the design maximum virtual junction
temperature, these ratings should not be exceeded. Due to variation in individual device electrical characteristics and thermal
resistance, the built-in thermal overload protection may be activated at power levels slightly above or below the rated dissipation.

recommended operating conditions over recommended operating free-air temperature range (unless
otherwise noted)

tn
:::r
CD
CD

....

o

Input voltage range, VI

High-level ENABLE input voltage, VIH
low-level ENABLE input voltage, Vil (see Note 21
Output current range, 10

DEVICE
Tl75 M05
Tl75 MOB
TL75 Ml0

MIN
6
9
11

Tl75 M12
Tl751M
Tl751M

13
2
-0.3

Tl75
Tl75
Tl75

Operating virtual junction temperature range, TJ

M
M
M

C
Q

MAX
26
26
26
26
15
O.B
750
125
125

0
-40

UNITS

V

V
mA
°C

Note 2: The algebraic convention, in which the least positive (most negative) value is designated minimum, is used in this data sheet
for 'EiiIABi:E voltage leve)s and temperature only.

TL750M05 and TL751M05 electrical characteristics at 25°C free-air temperature, VI - 14 V,
10 - 300 mA, ENABLE at 0 V for TL751M05 (unless otherwise noted)
TEST CONDITIONS (s•• Note 3)

PARAMETER
Output voltage
Input regulation

Ripple rejection
Output regulation
Dropout voltage
Output noise voltage
Bias current

VI = 6 V to 26 V, 10 = 0 to 750 mA

IT = 25°C
I A
TA - TJ niin to 125°C

MIN
4.95
4.9

TYP
5
10
12
55
20

VI = 9 V to 16 V, 10 = 250 mA
VI = 6 V to 26 V, 10 = 250 mA
VI = BVto lBV,f = 120Hz
10 = 5 mA to 750 mA
10 - 500 mA
10 = 750 mA
f = 10 Hz to 100 kHz

500
60

10 = 750 mA
10 - 10 mA

MAX
5.05
5.1
25
50
50
0.5
0.6

UNIT
V
mV
dB
mV
V
~V

75
5

mA

NOTE 3: Pulse testing techniques are used to maintain the junction temperature as close to the ambient temperature as possible. Thermal
effects must be taken into account separately. All characteristics are measured with a O.1-"F capacitor across the input and
a 10-"F capacitor on the output with equivalent series resistance within the guidelines shown in Figure 4.

2-164

TEXAS . "

INSTRUMENTS
POST OFFICE BOX 855012 • DALLAS, TEXAS 75266

TL750M, TL751M SERIES
LOW-DROPOUT VOLTAGE REGULATORS
TL750M08 and TL751M08 electrical characteristics at 25°C free-air temperature. VI 10 = 300 mAo ENABLE at 0 V for TL751M08 (unless otherwise noted)
TEST cONDmONs (saa Nota 3)

PARAMETER

MIN

TYP

MAX

7.92

8

B.08

Output voltage

IT = 25°C
VI = 9 V to 26 V. 10 = 0 to 750 mA I A
TA = TJ min to 125"C

Input, regulation

VI = 10 V to 17 V. 10 = 250 mA
VI = 9 V to 26 V. 10 = 250 mA

12
15

Ripple rejection

VI = 11 Vt021 V.I = 120Hz

Output regulation

10 = 5 mA to 750 mA

55
24

Dropout voltage
Output noise voltage
Bias current

7.84

14 V.
UNIT
V

B.16

mV
dB
mV
0.5

10 = 500 mA

V

0.6

10 = 750 mA
I - 10 Hz to 100 kHz

500

10 = 750 mA

60

10 = 10mA

/JoV
75
5

...

mA

II)

TL750M10 and TL751M10 electrical characteristics at 25°C free-air temperature. VI .. 14 V.
10 = 300 mAo ENABLE at 0 V for TL751M10 (unless otherwise noted)
TEST CONDITIONS (sea Note 3)

PARAMETER

,I TA

Output voltage

- 25°C
YI = 11 V to 26 V. 10 = 0 to 750 mAL
°
TA=TJminto125C

Input regulation

VI = 12 V to 18 V. 10 = 250 mA
VI = 11 V to 26 V. 10 = 250 mA

Ripple rejection

VI-13Vt023V.I -120Hz

Output regulation

10 = 5 mA to 750 mA
10 = 500 mA

Dropout voltage
Output noise voltage
Bias current

MIN
9.9

TYP
10

9.8

MAX
10.1

V

60

dB

30

mV
0.5

V

0.6

10 = 750 mA
I = 10 Hz to 100 kHz

1000

10 - 750 mA

60

10 = 10 mA

C

mV

20
55

.s::

CJ)

...caca

UNIT

10.2
15

Q)
Q)

p.V
75
5

mA

TL750M12 and TL751M12 electrical characteristics at 25°C free-air temperature. VI .. 14 V.
10 = 300 mAo ENABLE at 0 V for TL751M12 (unless otherwise noted)
TEST CONDITIONS (sea Nota 3)

PARAMETER

Output voltage
Input regulation

,IT = 25°C
VI = 13 V to 26 V. 10 = 0 to 750 mAl A
TA - TJ min to 125°C
VI = 13 V to 26 V. 10 = 250 mA
VI = 13 V to 23 V. I = 120 Hz

Output regulation

10 = 5 mA to 750 mA

Output noise voltage
Bias current

TYP
12

11.76

VI = 14 V to 19 V. 10 = 250 mA

Ripple rejection

Dropout voltage

MIN
11.88

MAX
12.12

mV

60

dB
mV

30

10 - 500 mA

0.5

10= 750 mA
I = 10 Hz to 100 kHz

0.6
1000
60

10 = 750 mA
10 = 10 mA

V

12.24
15
20

55

UNIT

V
p.V

75
5

mA

NOTE 3: Pulse testing techniques are used to maintain the junction temperature as close to the ambient temperature as possible.
Thermal effects must be taken into account separately. All characteristics are measured with a O.1-I'F capacitor across the
input and a 10-p.F capacitor on the output with equivalent series resistance within the guidelines shown in Figure 4.

TL751Mxx electrical characteristics at 25°C free-air temperature. VI

14 V. 10 .. 300 mA
MIN

PARAMETER
Response time. ENABLE to output

TYP

MAX

50

TEXAS . "

INSTRUMENTS
POST OFFICE BOX 655012 • DALLAS, TEXAS 75265

2-165

TL750M, TL751M SERIES
LOW·DROPOUT VOLTAGE REGULATORS
MAXIMUM RATINGS
TRANSIENT INPUT VOLTAGE
vs
TIME
60

>

..

50

1\

\

I

•

CII

~

0

40

i\.

'"

>
S

0.
..5 30

'II.

""--..

~

·sc

I!

"- ...........

tr - 11 ms

20

~ ...........

.I

....

I
:;- 10 TA - 25°C
-VI - 14 V + 46e (-t/0.230)

fort2:5ms

o

I

o

I

100

I

I

200
300
400
t-Time-ms

-500

600

FIGURE 1
FREE-AIR TEMPERATURE
DISSIPATION DERATING CURVE
2000

~

1800

b 1600
11400

~ 1200
5 1000

.
'c"

~

E

'"'"

800
600

~ 400

~

200

o
25

CASE TEMPERATURE
DISSIPATION DERATING CURVE
25
~
I

'"'"

c
.2 20

"-

1ii
0.

.
.

'iii

is 15

'"'" "'-

'c"
'"
0

.~

'" ""'-

Derating factor - 16 mW/·C
R6JA '" 62.5·C/W

125
75
50
100
TA - Free-Air Temperature- ·C

0

10

u
E
E

'"

'"
':e.."

150

5

o

~

~

Derating Factor - 181.8 mW/·C
above 40·C
R6JC '" 5.5·C/W

25

TEXAS . "

INSTRUMENTS
POST OFFICE BOX 655012 • DALLAS. TEXAS 75265

~

75
50
100
125
Tc-Case Temperature-·C

FIGURE 3

FIGURE 2

2-166

~

150

TL750M. TL751M SERIES
LOW·DROPOUT VOLTAGE REGULATORS
TRANSIENT RESPONSE
61L
APPLIED LOAD
CURRENT

T]

.~~

LOAD
VOLTAGE

EQUIVALENT SERIES RESISTANCE OF OUTPUT CAPACITOR
vs

VI

c:

.,I
!"

'5

C'

W'

I

a:

CIl

w

o~~~~
o
0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

.1IL -Load Current Range-A

FIGURE 4

TEXAS ."

INSTRUMENTS
POST OFFICE BOX 655012 • DALLAS. TEXAS 15265

2-167

C

m
r+
m

en

::r
CD
CD

r+

en

2-168

SERIES TL780
POSITIVE VOLTAGE REGULATORS
02643, APRIL 1981-REVISED AUGUST 1988

•

± 1 % Output Tolerance at 25°C

•

± 2% Output Tolerance Over Full Operating

NOMINAL
OUTPUT

REGULATOR

VOLTAGE

Range

5 V

TL780-05C

•

Thermal Shutdown

12 V

TL780-12C

•

Internal Short-Circuit Current Limiting

15 V

TL780·15C

•

Pinout Identical to uA 7800 Series

•

Improved Version of uA7800 Series

KC PACKAGE
(TOP VIEW)

Ell

OUTPUT
COM MOM
INPUT

description
Each fixed-voltage precIsion regulator in this
series is capable of supplying 1.5 amperes of
load current. A unique temperaturecompensation technique coupled with an
internally trimmed bandgap reference has
resulted in improved accuracy when compared
to other three-terminal regulators. Advanced
layout techniques provide excellent line, load,
and thermal regulation. The internal current
limiting and thermal shutdown features make the
devices essentially immune to overload.

THE COMMON TERMINAL IS IN
ELECTRICAL CONTACT WITH
THE MOUNTING BASE
TO-220AB

schematic
r-~~------------------~~--~~------------------.-----.----------t-INPUT

'------+--__._---+- OUTPUT

L-~~--__~----__----~~---4~------_~---+_~------~~--------COMMON

PRODUCTION DATA documents contain information
currant 8S of publication date. Products conform to
specifications per the terms of Texas Instruments

:~C~~:~~i~a[::ru~a ~!:~~~ti:r :1~O::~:::::t::S~S not

TEXAS

~

INSTRUMENTS
POST OFFICE BOX 655012 • DALLAS, TEXAS 75265

Copyright © 1981, Texas Instruments Incorporated

2-169

SERIES TL780
POSITIVE VOLTAGE REGULATORS
absolute maximum ratings over operating temperature range (unless otherwise noted)
Input voltage ............................................................. 35 V
Continuous total dissipation at 25°C free-air temperature (see Note 1) . . . . . . . . . . . . . . . . . .. 2 W
Continuous total dissipation at (or below) 25°C case temperature (see Note 1) . . . . . . . . . . .. 15 W
Operating free-air, case, or virtual junction temperature range .................... 0 to 150°C
Storage temperature range. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. - 65 to 150°C
Lead temperature 1,6 mm (1/16 inch) from case for 10 seconds. . . . . . . . . . . . . . . . . . . . .. 260°C

•

NOTE 1: For operation above 25 °C free-air or case temperature, refer to Figures 1 and 2. To avoid exceeding the design maximum virtual
junction temperature, these ratings should not be exceeded. Due to variations in individual device electrical characteristics and
thermal resistance, the built-in thermal overload protection may be activated at power levels slightly above or below the rated
dissipation.

FREE-AIR TEMPERATURE
DISSIPATION DERATING CURVE
2000
1800

16

1"'-

1600
1400

:!:

1000

c

800

~

E

400

::

200

.S

:E

0
.;:

III
CL

'"

~

600

::I

25

50

75

\

12

\

'iii
,!! 10
C

..
::I

'\

0

::I
C

--e

~

0

u

Derating factor - 16 mW/oC ' "
R6JA ~ 62.5 °C/w

o

\

I 14
c

'" "'-

1200

~

CASE TEMPERATURE
DISSIPATION DERATING CURVE

100

E
::I
E

"-

125

'>(

"'-

III

:E

150

8

\

6

\

4
2

o

\

Derating factor - 0.25 W/oC
above 90°C
R6JC ~ 4°C/W

25

50

75

100

125

TA -Free Air Tamperature- °C

Tc-Case Temperature-·C

FIGURE 1

FIGURE 2

\

\
150

recommended operating conditions
MIN
Input voltage, VI

I TL780-05C
I TL7S0-12C
I TL7S0-15C

7

MAX
25

14.5

30

17.5

30
1.5

0

125

Output current, 10

Operating virtual junction temperature, TJ

2-170

TEXAS . "

INSTRUMENTS
POST OFFICE BOX 655012 • DALLAS, TEXAS 75265

UNIT
V
A
DC

SERIES TL780
POSITIVE VOLTAGE REGULATORS
TL 780-05C electrical characteristics at specified virtual junction temperature, VI - 10 V, 10 - 500 mA
(unless otherwise noted)
TEST CONDITIONst

PARAMETER
Output voltage
Input regulation

Ripple rejection
Output regulation

Output resistance
Temperature coefficient
of output voltage

Output noise voltage
Dropout voltage

10

~

5 mA to 1A,

VI

~

7 V to 20 V

P s 15W,

25°C
OOCto 125°C

VI ~ 7 V to 25 V
~

VI

~

1- 120 Hz

I

~

Short-circuit output current

4.9

5.1

~

7 V to 25 V

10
VI

~

5 mA to 1 A

~

35 V

5

0.5

5

85
25

1.5

15

0.25

25°C

75

25°C

2

25°C

5

O°Cto 125°C

Peak output current

UNIT
V
mV
db

4

OOC to 125°C

1 A

VI

70

0.5

0.0035

Bias current
Bias current change

5.05

25°C

5 mA

~

MAX

5

OOCto 125°C

10 Hz to 100 kHz

~

10

OOCto 125°C

5 mA to 1.5 A

10 ~ 250 mA to 750 mA
I ~ 1 kHz
10

TYP

25°C

8 V to 12 V

VI - 8Vto 18V,

10

MIN
4.95

mV

II
....

!l
mV/oC

U)

~V

II)
II)

V
8

0.7

1.3

0.003

0.5

mA

J:

UJ

mA

25°C

750

mA

25°C

2.2

A

....COCO

C

TL 780-12C electrical characteristics at specified virtual junction temperature, VI ... 19 V, 10 ... 500 mA
(unless otherwise noted)
PARAMETER
Output voltage

Input regulation
Ripple rejection

Output regulation
Output resistance
Temperature coefficient

01 output voltage

TEST CONDITIONst

10

~

5 mA to 1 A,

VI

~

14.5 V to 27 V

VI

~

14.5 V to 30 V

MIN

P s 15 W,

25°C

10

~

25°C
I

~

120 Hz

Output noise voltage

I

Dropout voltage

10

~

OOC to 125°C

5 mA to 1.5 A

10 250 mA to 750 mA
I ~ 1 kHz
10

5 mA

25°C

~

Short-circuit output current

10

~

5 mA to 1 A

VI

~

35 V

12

1.2

12

80

V
mV
dB

6.5

60

2.5

36

mV

OOC to 125°C

0.6

mV/oC

25°C

180

~V

25°C

2

25°C

5.5

1 A

VI - 14.5 V to 30 V

12.24
1.2

UNIT

0.0035

Bias current
Bias current change

65

MAX

12 12.12

OOCto 125°C

10Hzto 100kHz

~

TYP

OOCto 125°C 11.76

VI - 16 V to 22 V
VI ~ 15 V to 25 V,

11.88

OOCto125°C

Peak output current

!l

V
8

0.4

1.3

0.03

0.5

rnA
rnA

25°C

350

mA

25°C

2.2

A

tPulse testing techniques are used to maintain the junction temperature as close to the ambient temperature as possible. Thermal effects
must be taken into account separately. All characteristics are measured with O.331'F capacitor across the input and a O.221'F capacitor
across the output.

TEXAS . "

INSTRUMENlS
POST OFFICE BOX 655012 • DALLAS. TEXAS 75265

2-171

SERIES TL780
POSITIVE VOLTAGE REGULATORS
TL7S0-1 5C electrical characteristics at specified virtual junction temperature. VI - 23 V. 10 - 500 rnA
(unless otherwise noted)
TEST CONDITIONSt

PARAMETER
Output voltage
Input regulation
Ripple rejection

Output regulation

E

Output resistance
Temperature coefficient

of output voltage

= 5 mA to 1 A,
= 17.5Vto30V
= 17.5Vto30V
= 20 V to 26 V

P s 15W,

VI - 18.5 V to 28.5 V.

f - 120 Hz

10
VI
VI
VI

= 5 mA to 1.5 A
10 = 250 mA to 750
f = 1 kHz

25°C
OOC to 125°C

=

OOC to 125°C

f

Dropout voltage

10

25°C

mA

5 mA

= 10 Hz to
=1A

Output noise voltage

Short-circuit output current

10
VI

15.15

14.7

60

15.3
1.5

15

1.5

15

75

UNIT
V
mV
dB

7

75

2.5

45

mV

0.0035

OOC to 125°C

0.62

mV/oC

25°C

225

p.V

25°C

2

25°C

5.5

100kHz

= 17.5 V to 30 V
= 5 mA to 1 A
= 35 V

VI

MAX

15

OOC to 125°C

Bias current
Bias current change

TYP

25°C

10

10

MIN
14.85

OOCto 125°C

Peak output current

Il

V
8

0.4

1.3

0.02

0.5

mA
mA

25°C

230

mA

25°C

2.2

A

tPulse testing techniques are used to maintain the junction temperature as close to the ambient temperature as possible. Thermal effects

must be taken into account separately. All characteristics are measured with a 0.33 I'F capacitor across the input and a 0.22 p.F capacitor
across the output.

TYPICAL APPLICATION DATA

INPUT

TL 780

0

J-----4I.....,;..;..;

C
Cl - 0.33 "F - 1 '
(Saa Nota AI

-::!:-

C2 - 0.22 p.F-1'
(Saa Note 81

Notes: A. Cl required if regulator is far from power supply filter.
B. C2 not required for stability, however transient response is improved.
C. Permanent damage can occur if output is pulled below ground.

2-172

TEXAS . "

INSTRUMENTS
POST OFFICE BOX 655012 • DALLAS, TEXAS 75265

-::!:-

TL783C
HIGH-VOLTAGE ADJUSTABLE REGULATOR
SEPTEMBER 1981-REVISED SEPTEMBER 1988
KC PACKAGE

• Output Adjustable from 1.25 V to 125 V

(TOPVIEWI

• 700-mA Output Current
• Full Short-Circuit, Safe-Operating-Area, and
Thermal Shutdown Protection
• 0.001

%N Typical Input Regulation

THE OUTPUT TERMINAL IS IN
ELECTRICAL CONTACT WITH
THE MOUNTING BASE

• 0.15% Typical Output Regulation
• 76-dB Typical Ripple Rejection

TO-220AB

•

• Standard TO-220AB Package

...en
CD
CD

.s:.

CJ)

description
The TL783C is an adjustable three-terminal positive-voltage regulator with an output range of 1.25 V to 125 V
and a DMOS output transistor capable of sourcing more than 700 mAo It is designed for use in high-voltage
applications where standard bipolar regulators cannot be used. Excellent performance specifications ...
superior to those of most bipolar regulators. _. are achieved through circuit design and advanced layout
techniques.

...asas

C

As a state-of-the-art regulator, the TL783C combines standard bipolar circuitry with high-voltage doublediffused MOS transistors on one chip to yield a device capable of withstanding voltages far higher than
standard bipolar integrated circuits. Because of its lack of secondary breakdown and thermal runaway
characteristics usually assoicated with bipolar outputs, the TL783C maintains full overload protection while
operating at up to 125 V from input to output. Other features of the device include current limiting, safeoperating-area (SOA) protection, and thermal shutdown. Even if the adjustment pin is inadvertently
disconnected, the protection circuitry remains functional.
Only two external resistors are required to program the output voltage. An input bypass capacitor is necessary
only when the regulator is situated far from the input filter. An output capacitor, although not required, will
improve transient response and protection from instantaneous output short-circuits. Excellent ripple rejection
can be achieved without a bypass capacitor at the adjustment terminal.

functional block diagram

~~--------------~----------~~~------~-----.~--vo

R1
ADJUST

R2

=
PRODUCTIOI DATA d••• montsoontain information
cllrrant 81 of publicatian da'l. Predacts canfanD to

spacificatioRs par the tIIrms af Tlus Instruments

=~:=i~·i~:1~1i =:~:; :.r:=::~~" not

Copyright © 1983. Texas Instruments Incorporated

TEXAS •

INSTRUMENlS
POST OFFICE BOX 655012 • DALLAS, TEXAS 75265

2-173

TL783C
HIGH-VOLTAGE ADJUSTABLE REGULATOR
absolute maximum ratings over operating temperature range (unless otherwise noted)
Input-to-output differential voltage, VI - Vo . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 125 V
Continuous total dissipation at (or below) 25°C free-air temperature (see Note 1) . . . . . . . . . . . . . .. 2 W
Continuous total dissipation at (or below) 25°C case temperature (see Note 1) ............... 20 W
Operating free-air, case, or virtual junction temperature range. . . . . . . . . . . . . . . . . . . . . . O°C to 150°C
Lead temperature 1,6 mm (1/16 inch) from case for 10 seconds . . . . . . . . . . . . . . . . . . . . . . .. 260°C
NOTE 1: For operation above 25'C free-air or case temperature, refer to Figures 1 and 2. To avoid exceeding the design maximum virtual
junction temperature, these ratings should not be exceeded. Due to variations in individual device electrical characteristics and
thermal resistance, the built-in thermal overload protection may be activated at power levels slightly above or below the rated
dissipation.

FREE-AIR TEMPERATURE
DISSIPATION DERATING CURVE

C

2000

C»
C»

3:

en
:r

I
c 1600

0+

CD
CD

0+
(I)

E

1800

i"- 1400

'iii

is.
,.
,.c
0

1200
1000

'E0

800

,.

600

u
E
.§

"
IV

:::E

'"""

22

'"'"

25

50

20

'!"-

16

.
.,.,.

'iii

is

~

18

'\
'\

14

\

12

\

0

""

200

o

3:
I
c

'"

75

100

..,cc

10

u
,.E
E

6

0

Derating factor - 16 mW/oC ' "
R6JA ~ 62.5°C/W

400

CASE TEMPERATURE
DISSIPATION DERATING CURVES

'"""

125

'j(

\

4

IV

:::E

150

'\

8

2

o

25

TA -Free-Air Temperature- °c
FIGURE 1

'\
'\
\

Derating factor - 250 mW/oC
above 70°C
ROJC ~ 4° C/W
50

75

100

125

150

Tc-Case Temperature- °c
FIGURE 2

recommended operating conditions
Input·to'output voltage differential, vI - Vo
Output current, 10

MAX

15

125
700
125

a

Operating virtual junction temperature, TJ

2-174

MIN

TEXAS •

INSTRUMENTS
POST OFFICE BOX 655012 • DALLAS, TeXAS 75265

UNIT
V
rnA

'C

TL783C
HIGH-VOLTAGE ADJUSTABLE REGULATOR
electrical characteristics at VI - Vo
noted)
PARAMETER

= 25 V, 10

0.5 A, TJ

O°C to 125°C (unless otherwise

TEST CONDITIONSt

Input regulation t

VI- Va - 20Vlo 125 V,

Ripple rejection

aVI(p_p) - 10 V,

Va -10V,

10 - 15 mA 10700 mA,

TJ - 25'C

10 - 15 mA to 700 mA,

P

P =s rated dissipation

MIN

MAX

0.001

0.Q1

TJ - O'C 10 125'C

0.004

0.02

1- 120 Hz

Output regulation

s

TYP

TJ - 25'C

rated dissipation

66

long-term drift

See Note 2

Output noise voltage

l-l0Hzlol0kHz,

25

Va" 5V
Va s 5V

0.15

0.5

%

20

70

mV

Va" 5V

0.3

1.5

%

VI - Va - 125 V,
TJ - 25'C

VI Va - 25 V,
VI- Va - 15V,

%

0.2

%

0.003

%

VI
VI

25 V,
Va
Va -125V,

15
1- 1 ms

II
...
U)

Q)
Q)

mA

.c

1100

t - 30 ms
t = 30 ms
t - 30 ms

(1J

715
700

900

100

250

Adjustment-terminal

current

t

mV

0.4

Minimum output current to
VI- Va -125V
maintain regulation

Peak output current

dB

7.5

with temperature
1000 h atTJ - 125'C,

%(V

Va s 5V

Output voltage change
Output voltage

76

UNIT

Change in adjustmentterminal current

VI- Va - 15Vlo 125V,

10 - 15 mA 10 700 mA,

P :s rated dissipation

Reference voltage (output
toADJ)

VI - Va - 10 V 10 125 V,

10 - 15 mA 10 700 mA,

P s rated dissipation

1.2

...caca

mA

83

110

IlA

0.5

5

IlA

1.27

1.3

C

V

Pulse testing techniques are used to maintain the Junction temperature as closelc the ambient temperature as possible. Thermal effects must be taken Into account
separately.

:t Input regulation is expressed here as the percentage change in output voltage per l-volt change at the Input.
NOTE 2: Since long-term drift cannot be measured on the Individual devices prior to shipment, this specification is not intended to be a guarantee or warranty. It
is an engineering estimate of the average drift to be expected from lot to lot.

TEXAS . "

INSTRUMENTS
POST OFFICE BOX 655012 • DALLAS, TEXAS 75265

2-175

TL783C
HIGH-VOLTAGE ADJUSTABLE REGULATOR
TYPICAL CHARACTERISTICS
OUTPUT CURRENT LIMIT
vs
INPUT -TO-OUTPUT VOLTAGE DIFFERENTIAL
2.0 r---..,---,---.---..,-----,
tw - 1 rns

1.8

1.8

E

C

C»
r+
C»

en
::T

~

"

()

;
CI.
;


I

"

103

104

~I

100

1000

'0 1.27

>
"g

I

I

10 5

106

~

-

1.28

0>

1.26

'"

1.25

I

1! 1.24

VI = 35 V
Vo = 10 V
10 - 500 mATJ - 25°C
102

10

=[20
10 = 15 mA

~

~

10- 3

10- 4
10 1

L

1.29 I--

/'

!!
of

o'"

C

1111

REFERENCE VOLTAGE
vs
VIRTUAL JUNCTION TEMPERATURE

102

U
I:

en

FIGURE 8

OUTPUT IMPEDANCE
vs
FREQUENCY

.

..r:.

f- Frequency- kHz

FIGURE 7

I

Q)
Q)

r'\

...caca

0.1

0.01

10-Output Current-mA

c:

PI
...

1Ol'F

~

50

20

0

o

i"-

70

>

1.23

107

1.22
-75-50-25 0

f - Frequency - Hz

25

50 75100125150175

TJ-Virtual Junction Temperature- °C

FIGURE 9

FIGURE 10

TEXAS . "

INSTRUMENTS
POST OFFICE BOX 655012 • DALLAS, TeXAS 75265

2-177

TL783C
HIGH-VOLTAGE ADJUSTABLE REGULATOR
TYPICAL CHARACTERISTICS
ADJUSTMENT-TERMINAL CURRENT
vs
VIRTUAL JUNCTION TEMPERATURE

90

...

E

E
~

"

86

D)

~

84

D)

'6'

C

r+

rn

:r
CD
CD

l

VI - 25 V
88 _ Va - Vref
10 - 500 mA


I

&

~
o

>
;

&.

101---+--+--F'--+--+-

£!
Q

V
o

151---+--t--+_-t--t,....~

OL-~

25

75

50

125

100

__- L__

-75 -50 -25

FIGURE 11

I -0,1
o

c

'l'

III

'tQ -0,2
~

>

~
o"

I

I

I

~

"-

6- 0 ,4

E
~
(,)
"

81----+---+-~~~~~-~

61---~~~~~-_r--+_-~

~

'"

;
o

I

41-----I---+---+---t---~

9

~

21-----I---+---+----!-----I
-0,5

o

25

50

75

100

125

T J- Virtual Junction Temperature - °C

150

OL-__

~

o

____-L____L -__

25

50

~

75

VI-Input Voltage-V

FIGURE 13

FIGURE 14

2-178

~

101---~---+---t---~-~

~

-0,3

__

100 125

12r---,---.---.--.----,

r-- r--. r--......

&

L-~

75

MINIMUM OUTPUT CURRENT
TO MAINTAIN REGULATION
vs
INPUT VOLTAGE

VI -25 V
Va = 5 V
10 - 15 mA to 700 mA

'#.

50

FIGURE 12

LOAD REGULATION
vs
VIRTUAL JUNCTION TEMPERATURE

I

__-L__

25

TJ-Virtual Junction Temperature- °C

TJ-Virtual Junction Temperature- °C

o

L-~

0

TEXAS ,.,
INSTRUMENTS
POST OFFICE BOX 655012 • DALLAS, TEXAS 75265

____

100

~

125

TL783C
HIGH-VOLTAGE ADJUSTABLE REGULATOR
TYPICAL CHARACTERISTICS
LINE TRANSIENT RESPONSE

LOAD TRANSIENT RESPONSE

TJ = 25°C

~

6

Co - 0

0.4
0.2

~

..,0

2

.!!!

>

.!!!

c

4

I
c

c

.g

>

c"

0

-2

II
...

0

> -4

~-0.2



I

~-0L-----L---~2----~3----~--~

4

2!

II)

VI = 35 V
Vo = 10 V
Co = 1 I'F
TJ m 25°C

:;
u 0.6

:;
Q.
:; 0.2
0
I

9

Q)
Q)

..c

(J)

0
0

Time-I's

40

80

120

160

200

240

...
tV
tV

C

Time-I's

FIGURE 16

FIGURE 15

DESIGN CONSIDERATIONS
The internal reference (see functional block diagram) is used to generate 1.25 V nominal (Vref) between the
output and adjustment terminals. This voltage is developed across R1 and causes a constant current to flow
through R1 and the programming resistor R2, giving an output voltage of:
Vo = Vref (1 +R2/R1) + ladj (R2)
or
Vo

~

Vref (1 +R2/R1).

The TL783C was designed to minimize ladj and maintain consistency over line and load variations, thereby
minimizing the ladj (R2) error term.
To maintain ladj at a low level, all quiescent operating current is returned to the output terminal. This quiescent
current must be sunk by the external load and is the minimum load current necessary to prevent the output
from rising. The recommended R1 value of 82 n will provide a minimum load current of 15 mAo Larger values
may be used if the input-to-output differential voltage is less than 125 V (see minimum .operating current
curve) or if the load will sink some portion of the minimum current.

bypass capacitors
The TL783C regulator is stable without bypass capacitors; however, any regulat'Jr will become unstable with
certain values of output capacitance if an input capacitor is not used. Therefore, the use of input bypassing is
recommended whenever the regulator is located more than four inches from the power-supply filter capacitor.
A 1-I.lF tantalum or electrolytic capaCitor is usually sufficient.

TEXAS ..,
INSlRUMENTS
POST OFFICE BOX 655012 • DALLAS. TEXAS 75265

2-179

TL783C
HIGH-VOLTAGE ADJUSTABLE REGULATOR
Adjustment-terminal capacitors are not recommended for use on the TL783C because they can seriously
degrade load transient response as well as create a need for extra protection circuitry. Excellent ripple
rejection is presently achieved without this added capacitor.
Due to the relatively low gain of the MOS output stage, output voltage drop-out may occur under large load
transient conditions. Addition of an output bypass capacitor will greatly enhance load transient response as
well as prevent drop-out. For most applications, it is recommended that an output bypass capacitor be used
with a minimum value of:
Co (j.lF) = 15NO

•

Larger values will provide proportionally better transient response characteristics .

protection circuitry

o

m
r+
m
(/)

:r
CD
CD

r+

til

The TL783C regulator includes built-in protection circuits capable of guarding the device against most
overload conditions encountered in normal operation. These protective features are current limiting, safeoperating-area protection, and thermal shutdown. These circuits are meant to protect the device under
occasional fault conditions only. Continuous operation in the current limit or thermal shutdown mode is not
recommended.
The internal protection circuits of the TL783C will protect the device up to maximum rated V, as long as certain
precautions are taken. If V, is instantaneously switched on, transients exceeding maximum input ratings may
occur, which can destroy the regulator. These are usually caused by lead inductance and bypass capacitors
causing a ringing voltage on the input. In addition, if rise times in excess of 10 Vlns are applied to the input, a
parasitic n-p-n transistor in parallel with the DMOS output can be turned on causing the device to fail. If the
device is operated over 50 V and the input is switched on rather than ramped on, a low-Q capacitor, such as a
tantalum or electrolytic should be used rather than ceramic, paper, or plastic bypass capacitors. A Q factor of
0.015 or greater will usually provide adequate damping to suppress ringing. Normally, no problems will occur
if the input voltage is allowed to ramp upward through the action of an ac line rectifier and filter network.
Similarly, if an instantaneous short circuit is applied to the outputs, both ringing and excessive fall times can
result. A tantalum or electrolytic bypass capaCitor is recommended to eliminate this problem. However, if a
large output capaCitor is used and the input is shorted, addition of a protection diode may be necessary to
prevent capacitor discharge through the regulator. The amount of discharge current delivered is dependent
on output voltage, size of capacitor, and fall time of V,. A protective diode (see Figure 17) is required only for
capacitance values greater than
Co (j.lF) = 3 x 104/(VO)2.
Care should always be taken to prevent insertion of regulators into a socket with power on. Power should be
turned off before removing or inserting regulators .

...
~

TL783C
INPUT

Vo

OUTPUT
ADJUST
R1

I

o

/.

~R2

T

FIGURE 17. REGULATOR WITH PROTECTIVE DIODE

2-180

TEXAS

~

INSTRUMENTS
POST OFFICE BOX 655012 • DALLAS, TEXAS 75265

TL783C
HIGH-VOLTAGE ADJUSTABLE REGULATOR
load regulation
The current set resistor (R1) should be located close to the regulator outputterminal rather than near the load.
This eliminates long line drops from being amplified through the action of R1 and R2 to degrade load
regulation. To provide remote ground sensing, R2 should be near the load ground.
TL783C
INPUT

1

Vo

Rline

~Rload

OUTPUT
ADJUST

R1

l

1

~

~

PI
...
II)

Q)
Q)

FIGURE 18. REGULATOR WITH CURRENT-SET RESISTOR

.s:::::

en

...

TYPICAL APPLICATION DATA
VI

r-_T.!.!L;.!7.!:.83~C::......-,
VI - 125 V

Vo = Vref (1

+

=

ctI
ctI

145 TO 200 V

C

~n

INPUT OUTPUTI---4........

R1
,--...!A::::D:::Jr::US::..:T~...J82

n
1-..........~..... 125V

R2
1.-_ _ _ _. . 8.2 kO. 2W

t NEEDED IF DEVICE IS MORE THAN 4 INCHES FROM
FILTER CAPACITOR

FIGURE 19. 1.25·V TO 115-V
ADJUSTABLE REGULATOR

FIGURE 20. 125-V
SHORT-CIRCUIT-PROTECTED
OFF-LINE REGULATOR

TEXAS . "

INSTRUMENTS
POST OFFICE BOX 655012 • DALLAS, TEXAS 75265

2-181

TL783C
HIGH-VOLTAGE ADJUSTABLE REGULATOR
TYPICAL APPLICATION DATA
125 V
1 Il
VI - 70 TO 125 V

10 Il

10 Il

E

TIPL762

1 kll
TL783C

C
m
r+

m

INPUT
OUTPUT 1-......- - .
ADJUST

Vo - 50 V @ 0.5 A

Vo - V,ef (1

R1

+ ~)

82 Il

+

82 Il

C/J

::T
CD
CD

r+

R2

3.3 kll. 1W

til

FIGURE 21. 50-V
REGULATOR WITH CURRENT BOOST

FIGURE 22. ADJUSTABLE
REGULATOR WITH CURRENT BOOST
AND CURRENT LIMIT

1- V,af
R
R

R

FIGURE 23. CURRENT-SINKING REGULATOR

2-182

FIGURE 24. CURRENT SOURCING REGULATOR

TEXAS .."

INSTRUMENTS
POST OFFICE BOX 655012 • DAl.LAS. TEXAS 75265

TL783C
HIGH-VOLTAGE ADJUSTABLE REGULATOR
TYPICAL APPLICATION DATA

Vcc

VI - 90 V

TL783C
INPUT
OUTPUT 1----4I~ 'V
OUTPUT
ADJUST

82

6.25

(l

II
...

(l

en

R2

II)
II)

V+
820

-='V

3.9 kO

INPUT

VOFFSET

= V,of

V-

FIGURE 25. HIGH-VOLTAGE
UNITY-GAIN OFFSET AMPLIFIER

(1

+~)

48 V

1

.c
en
ca
ca

...

C

FIGURE 26. 48-V. 200-rnA FLOAT CHARGER

TEXAS •

INSTRUMENTS
POST OFFICE BOX 655012 • DALLAS. TEXAS 75265

2-183

C

I»
r+
I»

en

:::r

CD
CD

r+

(II

2-184

TL1451AC
DUAL PULSE-WIDTH-MODULATION CONTROL CIRCUIT
D2730, FEBRUARY 1983-REVISED OCTOBER 1988

o OR N PACKAGE

• Complete PWM Power Control Circuitry

(TOP VIEW)

• Completely Synchronized Operation
CT
RT
ERROR
{IN
AMPLIFIER 1 IN 1 FEEDBACK
1 DEAD-TIME CONTROL
1 OUTPUT

• Internal Undervoltage Lockout Protection

REF

+

• Wide Supply Voltage Range
• Internal Short-Circuit Protection
• Oscillator Frequency ... 500 kHz Max
• Variable Dead Time Provides Control Over
Total Range

SCP
IN
ERROR
IN AMPLIFIER 2
2 FEEDBACK
2 DEAD-TIME CONTROL
2 OUTPUT

+}

GND '-c:._.....:::.Jf-'VCC

fI...

• Internal Regulator Provides a Stable 2.5-V
Reference Supply

CI)

description

CD
CD

The TL 1451 AC incorporates on a single monolithic chip all the functions required in the construction of two
pulse-width-modulation control circuits. Designed primarily for power supply control, the TL1451AC contains
an on-chip 2.5-V regulator, two error amplifiers, an adjustable oscillator, two dead-time comparators,
undervoltage lockout circuitry, and dual common-emitter output transistor circuits.
The uncommitted output transistors provide common-emitter output capability for each controller. The
internal amplifiers exhibit a common-mode voltage range from 1.04 V to 1.45 V. The dead-time control
comparator has no offset unless externally altered and may be used to provide 0% to 100% dead time. The
on-Chip oscillator may be operated by terminating RT (pin 2) and CT (pin 1). During low Vce conditions, the
undervoltage lockout control circuit feature locks the outputs off until the internal Circuitry is operational.

..c

o

...caca

C

The TL1451AC is characterized for operation from -20°C to 85°C.
functional block diagram
Vcc
RT
CT
(9)
(2)
(1)
2~~~~:~~E(~1~1)________________________1-__~__~____~ _____",

ERROR

j IN+ (14)

+

AMPLIFIER 2l 1N - (13)
2 FEEDBACK l.:(1::.<2)"-____.....-=O VT+, 1 RESIN and 2RESiN at VCC, I-:T'-!-Al-=_2:::5:;,O.,.:C:.....,:-:-:-:-:I-_ _ _ _ _-::.,.:5:--1
ICC Supply current lVSO and 2VSO at 0 V
TA = MIN to MAX
6.5
t For conditions shown as MIN or MAX, use the appropriate value specified in the recommended operating conditions.
*Typical values are at VCC = 5 V, TA = 25°C.

2-202

V

mV

total device
PARAMETER

UNIT

v

13.36

TA = 25°C
TA = MIN to MAX

MAX

0.4
4.5
4.55
4.6
10.8
10.9 11.02
13.5 13.64 13.77

VI = 5.5 V or 0.4 V
VI - 2.4 V

RESiN
VSO
RESET
RESET
SCR GATE DRIVE

TYP*

Vee- 1.5
Vee- 1.5

TEXAS . "

INSTRUMENlS
POST OFFICE BOX 655012 • DALLAS, TEXAS 75265

,.A
~A

,.A
mA

TL7770-S, TL7770-12, TL7770-1S
DUAL POWER-SUPPLY SUPERVISORS
switching characteristics. Vee - 5 V. eT open. TA = 25°e
PARAMETER
tpLH

Propagation delay time,
low-to-high-Ievel output

Propagation delay time,
tPHL
tpLH

high-to-Iow-Ievel output

Propagation delay time.
low-to-high-Ievel output

Propagation delay time.
tpHL

high-to-Iow-Ievel output

t,

Rise time

tf
t,

Fall time

tf

Fall time

TO
(OUTPUTI

RESIN

TYP

MAX

UNIT

RESET

270

500

ns

RESIN

RESET

270

500

ns

RESIN

RESET

270

500

ns

RESiN

RESET

270

500

ns

pulse duration

TEST CONDITIONS

See Figure 1

MIN

75

RESET

Rise time

Minimum effective
tw(minl

FROM
(INPUT)

150

RESET

50

RESIN

See Figu,e 2(al

150

VSU

See Figu,e 2(bl

100

ns

II
...
II)

75

ns
ns

CI)
CI)

.c

en

...caca

C

TEXAS . "

INSTRUMENTS
POST OFFICE BOX 655012 • DALLAS, TEXAS 75265

2-203

TL7770-5. TL7770-12. TL7770-15
DUAL POWER-SUPPLY SUPERVISORS
PARAMETER MEASUREMENT INFORMATION
5V

5V

---,I

VCC

511 !l

;u:;iiEsET- ,

I
I

E

1

J

I

J

15 pF

RESET

(See Note A)

15 pF

511 !l

GNO

(See Note A)

- - - .....

c

!D)

I

OUT

RESET OUTPUT CONFIGURATION

RESET OUTPUT CONFIGURATION
NOTE A: Includes jig and probe capacitance.

fA

FIGURE 1. RESET AND RESET OUTPUT CONFIGURATIONS

::r

CD
CD

r+

til

(8)

iiESiiii

(b) VSU
WAVEFORMS

FIGURE 2. INPUT PULSE DEFINITION

2-204

TEXAS ~

INSTRUMENTS
POST OFFICE BOX 655012 • DALLAS. TEXAS 76266

Tl7780-5, Tl7780-12, Tl7780-15

SYSTEM SUPERVISORS
D3016, NOVEMBER 1988

o OR N

• Power-On Reset Generator

PACKAGE

(TOP VIEW)

• Automatic Reset Generation After Voltage
Drop

lRESIN
lCT
1RESET
lRESET
lVSU
RWL
RWH
GND

• Wide Supply Voltage Range ... 3.5 V
to 18 V
• Dual Precision Undervoltage Comparators
• Temperature-Compensated Voltage
Reference

VCC
2RES(N
2CT
2RESET
2RESET
2VSU
WCLK
CWD

II
...

• True and Complementary Reset Outputs
• Externally Adjustable Pulse Duration

U)

• Outputs Valid When VCC Exceeds 1 V

Q)
Q)

• Precision Watchdog Function

.t:
CJ)

• Externally Set Timing Window

...
CO
CO

• Externally Set Delay

C

description
The TL7780 is a monolithic integrated circuit system supervisor designed for use as a reset controller in
microcomputer and microprocessor power supply systems. This device contains two independent supplyvoltage supervisors and one watchdog function. The voltage supervisors monitor the supply voltages at the
VSU pins. When VCC attains the minimum voltage of 1 V during power-up, the RESET and RESET outputs
become active (high and low, respectively) to prevent undefined operation. Taking RESIN low has the same
effect. To ensure that the microcomputer system has reset, the outputs remain active after the voltage at VSU
exceeds the threshold value VT + for a time delay (td) determined by an external timing capaCitor such that:
td = (constant to be determined) X capacitance
where td is in seconds and capacitance is in farads
The "watchdog" function monitors the system activity by sensing the positive edge of a programmergenerated signal at WCLK. An on-board current source generates a voltage ramp vcwd across the external
capacitor connected to CWD, which is compared to a timing window (set by external resistors connected to
RWL and RWH) at the instant of the occurrence of the positive edge of the programmer-generated signal
WCLK. If the positive edge of WCLK occurs before vcwd reaches the voltage at RWL or after vcwd reaches the
voltage at RWH, then 1RESET and 1RESET become active, resetting the system for a period td. A precision
current source, which tracks with the CWD charging current, allows RWL and RWH to be set by external
resistors, creating a temperature-compensated "watchdog" window.
To set up the required frequency window for WCLK, the following conditions must exist:
1) CWD > 100 pF, RWL > 10 k,O" RWH > 40 k'o'
2) fL

1
= --

x CWD, fH

1

=

RWH

--x CWD
RWL

The TL7780Q series is characterized for operation from -40°C to 125°C. The TL7780C series is characterized
for operation from O°C to 70°C.

PRODUCTION DATA do•• monts .ontain information
currant 8S of publication did•. Products conform to

specifications par the terms of Taxas Instruments

:=~~i~ai~:,~li ~~~::i:r :.r::~::::~:~~ not

Copyright @ 1988, Texas Instruments Incorporated

TEXAS . "

INSTRUMENTS
POST OFFICE BOX 655012 • DALLAS, TEXAS 75265

2-205

TL7780-5, TL7780-12, TL7780-15
SYSTEM SUPERVISORS
logic diagram (each channel)t
VCC~(1~6)~__~.-________~______________~--,

•

C

I»
r+
I»

en

::r
CD
CD

WCLK (10)

r+

en

RWL (6)
RWH (7)

WATCH DOG
(CHANNEL 1 ONLY)

CWO (9)

t Pin numbers for channell are shown; pin 16 is common to both channels.

functional timing diagram
tcI~~tcI

.----;1

I I

I

I I

I I

I
I

I
I

I I
I I

I

,.1___.,
I

I

::~
I

WCLK

I

I

I

I

I
I I

VSU

2-206

--------------~V~------

TEXAS . "

INSTRUMENTS
POST OFFICE BOX 655012 • DALLAS, TEXAS 75285

TL7780-5, TL7780-12, TL7780-15
SYSTEM SUPERVISORS
absolute maximum ratings over operating free-air temperature range (unless otherwise noted)
Supply voltage, VCC (see Note 1) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 V
Input voltage range 1RESIN, 2RESIN, 1VSU, 2VSU) ............................ -0.3 V to Vec
High-level output current 1RESET and 2RESET, IOH: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -20 mA
Low-level output current 1RESET and 2RESET, IOL: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 20 mA
Continuous total dissipation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . See Dissipation Rating Table
Operating virtual junction temperature range . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -40°C to 150°C
Storage temperature range . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -65°C to 150°C
Lead temperature 1,6 mm (1/16 inch) from case for 10 seconds ......................... 260°C
NOTE 1: All voltage values are with respect to network ground terminal.
DISSIPATION RATING TABLE
PACKAGE

TA

s

DERATING FACTOR

2S·C

POWER RATING

ABOVE TA =2S·C

TA

= 70·C

POWER RATING

...

TA = 12S·C

CI)

POWER RATING

D

950mW

7.6mW/"C

608mW

190mW

N

1000mW

12.5 mwrc

1000mW

312mW

CD
CD

.c

en

...caca

recommended operating conditions
Supply voltage, VCC
Input voltage, VI

ilRESIN, 2RESIN, 1VSU, 2VSU, VI,

See Note 2

MAX

3.5

18

V

-0.3

18

V
V

5

Output voltage (1 CT and 2CT), Vo
Output sink current (1 CT and 2CT), 10
High-level output current (1 RESET and 2RESET), 10H
Low-level output current (1 RESET and 2RESET), 10L
Operating free-air temperature, TA
NOTE 2:

ITL7780Q Series
ITL7780C Series

UNIT

MIN

50
-16

lolA
mA

16

mA

-40

125

0

70

C

·C

..
..
The algebraic convention, In which the least positive (most negative) value IS designated minimUm, IS used In thiS data sheet for Input
voltage levels and temperature only.

TEXAS ."

INSlRUMENTS
POST OFFICE BOX 665012 • DALLAS. TEXAS 75265

2-207

TL7780-5, TL7780-12, TL7780-15
SYSTEM SUPERVISORS
electrical characteristics over recommended ranges of supply voltage, Input voltage, output
current, and operating free-air temperature (unless otherwise noted)
supply supervisor section
PARAMETER

TEST CONDITIONS

VOH

High-level output voltage

RESET

10H - -15mA

VOL

LOW-level output voltage

RESET

10L

TL7780-12 (12-V sense, 1VSU)

E

= 25°C

TA

TL7780-5, TL7780-12, TL7780-15
Undervoltage threshold
(negative-going)

c

s:»
r+
s:»

(programmable sense, 2VSU)
TL7780-5 (5-V sense, 1VSU)

:::r

CD
CD

Hysteresis (VT +
Vhys
atVSU

r+

-

VT -)

4.55

4.6

10.8

10.9

11.02

13.5

13.64

13.77

1.485

1.5

1.515
4.64

TL7780-12 (12-V sense, 1VSU)

10.68

11.12

TL7780-15 (15-V sense, 1VSU)

13.36

13.91

1.47

1.53

(programmable sense, 2VSU)
TL7780-5 (5-V sense, 1VSU)

15

TL7780-12 (12-V sense, 1VSU)

36

TL7780-15 (15-V sense, lVSU)

= 25°C

TA

45

TL7780-5, TL7780-12, TL7780-15

til

UNIT
V

4.46

TL7780-5, TL7780-12, TL7780-15

en

MAX
0.4

4.5

TL7780-15 (15-V sense, 1VSU)

TYP

= 15mA

TL7780-5 (5-V sense, 1VSU)

VT-

MIN
VCC-1.5

V

V

mV

5

(programmable sense, 2VSU)

= 5.5 V or 0.4 V
= 18 V

II

Input current

RESIN

VI

10H

High-level output current

RESET

Va

10L

Low-level output current

RESET

Vo - 0

-10

IlA

50

IlA

-50

IlA

electrical characteristics over recommended ranges of supply voltage, input voltage, output
current, and operating free-air temperature, Ct at 0.1 IJF to GND (unless otherwise noted)
"watchdog" section
TEST CONDITIONst

PARAMETER

MIN

TYP

MAX

II

Input current

WCLK

Charging current

CWD

Vee - 3.5 Vto 18 V

45

55

IlA

Output current

RWLand RWH

Vce

= 3.5 Vto 18 V

45

55

IlA

VCC
VI

0.4

1.8

= 2.4 V

100

VI - 0.4 V

200

total device
PARAMETER
ICC

t

UNIT

Input threshold voltage

10

WCLK

= 3.5 V to 18 V

VT

Supply current

TEST CONDITIONS

VSU and RESIN at VCC

MIN

TYP

5
TA

= MIN to MAX

For conditions shown as MIN or MAX, use the appropriate value specified in the recommended operating conditions.

2-208

MAX

TEXAS •

INSTRUMENTS
POST OFFICE BOX 655012 • DALLAS, TEXAS 75265

6.5

V
IlA

TL7780-5, TL7780-12, TL7780-15
SYSTEM SUPERVISORS
switching characteristics, Vee = 5 V, er open, TA = 25°e (see Figure 1)
supply supervisor section
PARAMETER

FROM

TO

(INPUT)

(OUTPUT)

TEST CONDITIONS

MIN

TYP

MAX

UNIT

tpLH Propagation delay time, low-to-high-Ievel output

lRESIN

1RESET

100

500

ns

tpHL Propagation delay time, high-to-Iow-Ievel output

2RESIN

2RESET

100

500

ns

tpLH Propagation delay time, low-to-high-Ievel output

2RESIN

2RESET

100

500

ns

tpHL Propagation delay time, high-to-Iow-Ievel output
Rise time
tr

lRESIN

1RESET

100

500

ns

tf

Fall time

tr

Rise time

tf

Fall time

CL=15pF

75

1RESET or 2RESET

50
75

1RESET or 2RESET

50

ns
ns

PI
en

~

Q)
Q)

"watchdog" section
PARAMETER
tpLH Propagation delay time, low-to-high-Ievel output
tpHL Propagation delay time, high-to-Iow-Ievel output

FROM

TO

(INPUT)

(OUTPUT)

WCLK

lRESET

WCLK

1 RESET

TEST CONDITIONS

MIN

TYP

MAX

UNIT

CL-15pF,

100

500

ns

RWL = 60 kO,

100

500

ns

tpLH Propagation delay time, low-to-high-Ievel output

WCLK

1RESET

RWH = 60 kO,

100

500

ns

tpHL Propagation delay time, high-to-Iow-Ievel output
tpLH Propagation delay time, low-to-high-Ievel output

WCLK

1RESET

CWO = 2V

100

500

ns

WCLK

CWO

500

ns

WCLK

CWO

CWO = 15 pF
(probe capacitance)

100

tpHL Propagation delay time, high-to-Iow-Ievel output

100

500

ns

TEXAS ."

INSTRUMENTS
POST OFFICE BOX 655012 • DALLAS. TEXAS 15285

..c:

CJ)

ca
ca

~

C

2-209

E

c
C)

.....
C)
C/)

:::r

CD
CD

.....
til

2-210

uA723M, uA723C
PRECISION VOLTAGE REGULATORS
01063, AUGUST 1972-REVISED OCTOBER 1988

•

150-mA Load Current Without External
Power Transistor

•

Typically 0.02% Input Regulation and
0.03% Load Regulation (uA723M)

uA723M ... J PACKAGE
uA723C ... D, J, OR N PACKAGE
(TOP VIEW)

•

Adjustable Current Limiting Capability

•

Input Voltages to 40 V

•

Output Adjustable from 2 to 37 V

•

Direct Replacement for Fairchild ,.A723M
and ,.A723C

NC
CURR LIM
CURR SENS
ININ+
REF
VCC-

NC
FREO COMP
VCC+
Vc
OUTPUT
Vz
NC

II
...

uA723M ... U PACKAGE
(TOP VIEW)

description

U)

The uA723M and uA723C are monolithic
integrated circuit voltage regulators featuring
high ripple rejection, excellent input and load
regulation, excellent temperature stability, and
low standby current. The circuit consists of a
temperature-compensated reference voltage
amplifier, an error amplifier, a 150-mA output
transistor, and an adjustable output current
limiter.

CURR SENS
CURR LIM
INFREQ COMP
IN+
VCC+
REF
Vc
VCC- -...._ _~OUTPUT

Q)
Q)

.s:.

tn

...asas

C

NC-No internal connection

The uA723M and uA723C are designed for use in positive or negative power supplies as a series, shunt,
switching, or floating regulator. For output currents exceeding 150 mA, additional pass elements may be
connected as shown in Figures 4 and 5.
The uA723M is characterized for operation over the full military temperature range of - 55°C to 125°C.
The uA723C is characterized for operation from O°C to 70°C.

functional block diagram
FREQUENCY
COMPENSATION
TEMPERATURE·
COMPENSATED
REFERENCE
DIODE

INVERTING
INPUT

Vc

REF
NON·
INVERTING
INPUT

VCC-

PRODUCTION DATA documanls contain information

current as of publication data. Products conform to
spacifications par the tarms of Tax8s Instruments

:!~:~~i~ai~:ru1~ ~!:~~:i:; :.r::~::9t:~~ not

REGULATED
OUTPUT

CURRENT
LIMIT

CURRENT
SENSE

.,

D, J, AND N
PACKAGES
ONLY

I

I

Vz
L __
_ _ _ -I

Copyright © 1982, Texas Instruments Incorporated

TEXAS ..,
INSTRUMENTS
POST OFFICE BOX 655012 • DALLAS, TEXAS 75265

2-211

uA723M, uA723C
PRECISION VOLTAGE REGULATORS
absolute maximum ratings over operating free-air temperature range (unless otherwise noted)

•

Peak voltage from VCC + to VCC _ (t w :s; 50 ms) .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 50 V
Continuous voltage from VCC + to VCC _ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 40 V
Input-to-output voltage differential. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 40 V
Differential input voltage to error amplifier . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. ± 5 V
Voltage between noninverting input and VCC - . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 8 V
Current from VZ. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 25 mA
Current from REF . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 1 5 mA
Continuous total diSSipation (see Note 1) . . . . . . . . . . . . . . . . . . . . . .. See Dissipation Rating Table
Operating free-air temperature range: uA723M Circuits .................... -55°C to 125°C
uA 723C Circuits . . . . . . . . . . . . . . . . . . . . . . .. ooC to 70°C
Storage temperature range ......................................... - 65°C to 150°C
Lead temperature 1,6 mm (1/16 inch) from case for 60 seconds: J or U package ......... 300°C
Lead temperature 1,6 mm (1/16 inch) from case for 10 seconds: D or N package ........ 260°C

c
Q)

r+
Q)

NOTE 1: Power dissipation

= lI(standby) +

I(ref)l VCC

en

DISSIPATION RATING TABLE

:r
CI)
CI)

+ IVc - VOl 10.

PACKAGE

r+
(I)

TA s 25°C
POWER RATING

DERATING FACTOR

DERATE
ABOVE TA
25°C

TA - 70°C
POWER RATING

D

950mW

7.6 mW/oC

J (uA·M)
J (uA-C)

1000mW

11.0 mW/oC

59°C

880mW

1000mW

8.2 mW/oC

28°C

656 mW

N

1000 mW

9.2 mW/oC

41°C

736 mW

U

675 mW

5.4 mW/oC

25°C

432 mW

TA - 126°C
POWER RATING

608 mW
275 mW

135mW

recommended operating conditions
Input voltage, VI
Output voltage, Vo

Input-to-output voltage differential,
Output current, 10

2-212

Vc - Va

TEXAS . "

INSTRUMENTS
POST OFFICE BOX 655012 • DALLAS, TeXAS 75265

MIN

MAX

9.5

40

V

2

37

V

3

38
150

V
mA

UNIT

uA723M, uA723C
PRECISION VOLTAGE REGULATORS
electrical characteristics at specified free-air temperature (see Notes 2 and 3)
uA723M

TEST CONOITIONS t

PARAMETER

MIN

VI = 12 V to VI = 15 V

Input regulation

Ripple rejection

Output regulation

TYP

MAX

25°C

0.01%

0.1%

0.01%

0.1%

0.02%

0.2%

0.1%

0.5%

12 V to VI

~

40 V

25°C

=

15 V

Full range

f

~

MAX

VI = 12 V to VI

VI

=

50 Hz to 10kHz,

f = 50 Hz to 10kHz,

10 = 1 mAtala

=

Glre!) ~ 0

25°C

Glre!) ~ 5.F

25°C

74

86

dB

86

-0.03% -0.15%

-0.03% -0.2%
-0.6%

-0.6%

25'G

6.95

UNIT

0.3%

74

Full range

Reference voltage,

MIN

0.3%

25°C

SOmA

uA723C

TYP

7.15

7.35

7.15

2.3

7.5

3.5

2.3

4

0.002

0.015

0.003

0.015

6.8

fI
...

V

Vlref)
Standby current

VI

~

30 V,

10

~

25°C

0

rnA

en

Temperature
coefficient of

Full range

Q)
Q)

%I'G

.J:

output voltage
Short-circuit
output current

Output noise voltage

CJ)

RSG~10n,

BW
BW

=
=

Vo

~

0

25°C

65

65
20

100 Hz to 10 kHz.

Glre!) ~ 0

25'G

20

100 Hz to 10 kHz.

Glre!) ~ 5.F

25°C

2.5

rnA

...
CIS
CIS

.V

2.5

C

tFull range for uA723M is -55 DC to 125°C and for uA723C is oDe to 70°C.
NOTES: 2. For all values in this table, the device is connected as shown in Figure 1 with the divider resistance as seen by the error amplifier .:S 10 kO. Unless
otherwise specified, VI = Vee + = Ve

=

12 V, Vee _

=

0, Va

=

5 V, 10

=

1 rnA, Rse

=

0, and C{ref)

=

O.

3. Pulse testing techniques must be used that will maintain the junction temperature as close to the ambient temperature as possible.

schematic
VCC+

Vc

OUTPUT

I

- ------- - --,
6.2 V

I

D, J, ANO N

PACKAGES

I
I

L __ ~~_ ~N.!:.Y_ _ _ ...J

. .- - - - - - -

~~~~EE:SC;TlON

f - - - - - - - ~I~~~ENT
~________ ~~==:NT
VccREF

NONINVERTING
INPUT

INVERTING
INPUT

RESISTOR ANO CAPACITOR VALUES SHOWN ARE NOMINAL.

TEXAS

~

INSTRUMENTS
POST OFFICE BOX 655012 • DALLAS, TEXAS 75265

2-213

uA723M, uA723C
PRECISION VOLTAGE REGULATORS
TYPICAL APPLICATION DATA
TABLE 1. RESISTOR VALUES (kO) FOR STANDARD OUTPUT VOLTAGES
OUTPUT
VOLTAGE
(VI

•

cC»

FIXED
OUTPUT

OUTPUT
ADJUSTABLE

±5%

± 10% (SEE NOTE 41

APPLICABLE
FIGURES
(SEE NOTE 31

Rl

R2

(kO)
105

Rl
(km
2.2

Pl
(kO)
10

P2
(kO)
91

Rl

R2

(km
4.12

(km
3.01

(km
1.8

(km
0.5

(kO)
1.2

+100

7

(km
3.57

+250

7

3.57

255

2.2

10

240

1.5.6.9.11.
12 (41

3.57

3.65

1.5

0.5

1.5

+5.0

1.5.6.9.11.
12141

2.15

4.99

0.75

0.5

2.2

-6

3.1101

3.67

2.43

1.2

0.5

0.75

1.5.6.9.11.
12141
2,4. 15.6.
9.121

1.15

6.04

0.5

0.5

2.7

INote 51
-9

3.10

3.48

5.36

1.2

0.5

2.0

1.87

7.15

0.75

1.0

2.7

-12

3.10

3.57

8.45

1.2

0.5

3.3

2,4. 15.6.
9.121
2,4. 15. 6.
9.121

4.87

7.15

2.0

1.0

3.0

-15

3.10

3.57

11.5

1.2

0.5

4.3

7.87

7.15

3.3

1.0

3.0

-28

3.10

3.57

24.3

1.2

0.5

10

2,4. 15. 6.
9.121
7
7

21.0

7.15

5.6

1.0

2.0

-45

8

3.57

41.2

2.2

10

33

3.57
3.57

48.7
78.7

2.2

10
10

39
68

-100
-250

8

2.2

3.57
3.57

95.3
249

2.2
2.2

10
10

91
240

+9.0
+12
+15

(I)

±5%

OUTPUT
VOLTAGE
(VI

+3.6

(f)

r+

OUTPUT
ADJUSTABLE
± 10% ISEE NOTE 41
Rl
Pl
P2

1.5.6.9.11.
12 (41

+6.0

':r'
CD
CD

FIXED
OUTPUT

+3.0

r+

C»

APPLICABLE
FIGURES
(SEE NOTE 31

+28
+45
+75

8

NOTES: 3. The RI/R2 divider may be across either Vo or V Irefl' If the divider is across V Iref). use the figure numbers without parentheses.
If the divider is across VO, use the figure numbers in parentheses.
4. To make the voltage adjustable. the Rl/R2 divider shown in the figures must be replaced by the divider shown below.

Rl
PI
R2

ADJUSTABLE OUTPUT CIRCUIT

5. The device requires a minimum of 9 V between VCC+ and VCC- when

2-214

Va

TEXAS . "

INSTRUMENTS
POST OFFICE BOX 655012 • DALLAS. TeXAS 75265

is equal to or more positive than -9 V.

uA723M. uA723C
PRECISION VOLTAGE REGULATORS
TYPICAL APPLICATION DATA
TABLE 2. FORMULAS FOR INTERMEDIATE OUTPUT VOLTAGES
Outputs from + 2 to + 7 V

Outputs from +4 to + 250 V

[Figures 1,5,6,9, 11, 12, (4))

IFigure 7)

R2
Vo ~ Vlref) X R1 + R2

Vlref)
R2 - R1
Vo ~ -2- X --R1-;

R3

~

Current limiting

0.65 V

l(limit) '"

""""iiSC:

R4

...
II)

Outputs from + 7 to + 37 V

Outputs from - 6 to - 250 V

Foldback Current Limiting

[Figures 2.4,15,6,9, 11, 12))

[Figures 3,8, 10)

[Figure 6)

CI)
CI)

..c
Vo ~ Vlref) X

R1 + R2

R2

CIJ

Vlref)
R1 + '12
Vo ~ - - 2 - X --R-1-;

R3

~

Ilknee) '"

...asas

VOR3 + IR3 + R4) 0.65 V
RSC R4
;

C

R4
lOS'"

0.65 V
R3 + R4
RSC X

R4

NOTES: 3. The R1/R2 divider may be across either Va or V(ref)' If the divider is across V(ref) and uses figures without parentheses.
use figures with parentheses when the divider is across Va.
4. To make the voltage adjustable, the R1/R2 divider shown in the figures must be replaced by the divider shown at the right.
5. The device requires a minimum of 9 V between VCC+ and VCC- when Va is equal to or more positive than -9 V.

TEXAS ~

INSTRUMENTS
POST OFFICE BOX 655012. DALLAS, TEXAS 75265

2-215

uA723M, uA723C
PRECISION VOLTAGE REGULATORS
TYPICAL APPLICATION DATA

Vcc+

Vc
OUT

REF
REGULATEO
OUTPUT. Va

Vz

RSC

REGULATED
OUTPUT. Va

CL

R3
NONINV

CS
R1

INV

C

I»
r+
I»
U)

:::r

CD
CD

R2

R1 • R2
NOTES: A_ R3 = R1 + R2 for minimum "VO-

R1 • R2
NOTES: A. R3 =~for minimum "VO.

B. R3 may be eliminated for minimum component count.
Use direct connection (i.e., R3 = 0),

r+

(II

FIGURE 1. BASIC LOW-VOLTAGE REGULATOR
(VO z 2 TO 7 VOLTS)

B. R3 may be eliminated for minimum component count.

Use direct connection li.e .• R3 = 0).

FIGURE 2. BASIC HIGH-VOLTAGE REGULATOR
(VO - 7 TO 37 VOLTS)

2 k!l

R2
OUT
Vz

NONINV

CS

2N3997
2N5001

CL

R4 3 k!l

R3 3 k!l

REF

INV

(See Note 6)

REGULATED
OUTPUT. Va

REGULATED
OUTPUT. Va
R1

R1

100 pF

500 pF
R2

FIGURE 3. NEGATIVE-VOLTAGE REGULATOR

FIGURE 4. POSITIVE-VOLTAGE REGULATOR
(EXTERNAL N-P-N PASS TRANSISTOR)

NOTE 6: When 10-lead uA723U devices are used in applications requiring VZ, an external 6.2-V regulator diode must be connected in
series with the OUT terminal.

2-216

TEXAS . "

INSTRUMENTS
POST OFFICE BOX 655012 • DALLAS. TEXAS 75265

uA723M, uA723C
PRECISION VOLTAGE REGULATORS
TYPICAL APPLICATION DATA

6011
2N5001

Vcc+

Vc
OUT .......- -.....

REF

OUT

Vz

Vz

REF

C L I - - -.....

R1
NON·
INV

CS

_-_>--

....
R"'SC/lrll,.... REGULATED
OUTPUT, Vo
R3

II

CL
R1

RSC

INV .......

......._

NON·
INV

REGULATED
OUTPUT, Vo

R2

R4

CS
INV

R2

-=
FIGURE 5. POSITIVE-VOLTAGE REGULATOR
(EXTERNAL P-N-P PASS TRANSISTORI

-=

FIGURE 6, FOLDBACK CURRENT LIMITING

10 kll

10 kll

2N5241
ISee Note 6)

1N1826

REF
R4 3 k!l

R1
NON·
INV

es~---.

R2
Rse - 111

2N5241
ISoe Note 6)

Vz
CL

R3 3 k!l

NON·

es

INV

R3 3 k!l

R4 3 kll

R1

500 pF

'--+-_...___..._-t__-t__..... REGULATED
OUTPUT, Vo

FIGURE 7. POSITIVE FLOATING REGULATOR

500 pF

REGULATED
L---+-...-~--4--~~-~OUTPUT,VO

FIGURE 8. NEGATIVE FLOATING REGULATOR

NOTE 6: When 10-lead uA723U devices are used in applications requiring VZ, an external 6.2-V regulator diode must be connected in
series with the OUT terminal.

TEXAS . "

INSTRUMENTS
POST OFFICE BOX 655012 • DALLAS. TEXAS 75265

2-217

uA723M, uA723C
PRECISION VOLTAGE REGULATORS
TYPICAL APPLICATION DATA

3 kll

Vcc+

•

Vc

Il

,-----iREF
~~~~-+

L - 1.2mH
(See Note 7)

__r-.. REGULATED

OUTPUT, Vo

R1

C

1 kll

I»
r+
I»

en

::r

CD
CD

r+

FIGURE 9, POSITIVE SWITCHING REGULATOR

en

(See Note 5)
2N3997

R2
OUT
REF

Vz
CL

1 kll

NON·
INV

1 Mil

R1

CS
INV

15 pF

Il

1N4005

100pF~

L - 1.2 mH
(See Note 7)
REGULATED
OUTPUT, Vo

FIGURE 10. NEGATIVE SWITCHING REGULATOR
NOTES: 5. The device requires a minimum of 9 V between VCC+ and VCC- when Vo is equal to or more positive than -9 V.
6. When 10-lead uA723U devices are used in applications requiring VZ, an external 6.2-V regulator diode must be connected
in series with the OUT terminal.
7. lis 40 turns of No. 20 enameled copper wire wound on Ferroxcube P36/22-3B7 potted core, or equivalent, with an C.009-inch

air gap.

2-218

TEXAS ."

INSTRUMENTS
POST OFFICE BOX 655012 • DALLAS. TEXAS 75265

uA723M, uA723C
PRECISION VOLTAGE REGULATORS
TYPICAL APPLICATION DATA

V,
Vc

Vcc+

RSC

REGULATED
OUTPUT, Vo

OUT
REF

Vz

NONINV

CS

CL
Rl

fI

INV

R2
2 kG
INPUT FROM
SERIES 54174 LOGIC

NOTE A: Current limit transistor may be used for shutdown if
current limiting is not required.

FIGURE 11. REMOTE SHUTDOWN REGULATOR
WITH CURRENT LIMITING

V,
100 G

VCC+

2N3997
OUT

REF

Vz

NONINV

CS

1 kG

CL
Rl

REGULATED
OUTPUT, Vo

INV

(See Note 6)

R2

FIGURE 12. SHUNT REGULATOR
NOTE 6: When lO-lead uA723U devices are used in applications requiring VZ, an external 6.2-V regulator diode must be connected in
series with the OUT terminal.

TEXAS •

INsrRUMENTS
POST OFFICE BOX 655012 • DALLAS, TEXAS 75265

2-219

C

I»
r+
I»

rn
::r
CD
CD

r+

en

2-220

SERIES uA7800
POSITIVE-VOLTAGE REGULATORS
02154, MAY 1976-REVISEO APRIL 1988

•
•
•
•
•
•
•

•

3-Terminal Regulators

NOMINAL
OUTPUT

Output Current Up to 1.5 A

REGULATOR

VOLTAGE

No External Components
Internal Thermel Overload Protection
High Power Dissipation Capability

5V
6V

uA7805C
uA7806C

8V

uA7808C

v
10 v

uA7885C
uA7810C

12 V

uA7812C
uA7815C

8.5

Internal Short-Circuit Current Limiting
Output Transistor Safe-Area Compensation

v
18 v
24 v
15

Direct Replacements for Fairchild I'A7800
Series

description

uA7818C
uA7824C

...
U)

KC PACKAGE

This series of fixed-voltage monolithic
integrated-circuit voltage regulators is designed
for a wide range of applications. These
applications include on-card regulation for
elimination of noise and distribution problems
associated with single-point regulation. Each of
these regulators can deliver up to 1.5 amperes
of output current. The internal current limiting
and thermal shutdown features of these
regulators make them essentially immune to
overload. In addition to use as fixed-voltage
regulators, these devices can be used with
external components to obtain adjustable output
voltages and currents and also as the powerpass element in precision regulators.

II)
II)

(TOPVIEWI

..c

U)

THE COMMON TERMINAL IS IN

...

ELECTRICAL CONTACT WITH

C

CO
CO

THE MOUNTING BASE
TO-220AB

schematic
r-~~------~--------~----~~----~--INPUT

}-~-----+--+-----+--.--*---OUTPUT

~~~~~--~--~--~--~~------~-----COMMON

PRODUCTION DATA do.umants .ontsin infarmalion
currant .s of publication data. Predacts cenfarm to
_illoatio .. par tho term. of T.... Instruments

=~ri~a{::r~

:=::i:; :.r:::r:::u.~ not

Copyright @ 1982, Texas Instruments Incorporated

TEXAS ",
INSTRUMENTS
POST OFFICE BOX 655012 • DALLAS, TeXAS 75265

2-221

SERIES uA7800
POSITIVE·VOLTAGE REGULATORS
absolute maximum ratings over operating temperature range (unless otherwise noted)
uA78_ _ C

I
I

Input voltage

uA7824C

40

All others

35

Continuous total dissipation at 25°C free-air temperature (see Note 1)
Continuous total dissipation at (or below) 25°C case temperature (see Note 1)

o

Lead temperature 1,6 mm (1/16 inch) from case for 10 seconds

~

en

FREE-AIR TEMPERATURE
DISSIPATION DERATING CURVE

.. ..
CD
CD

(I)

260

NOTE 1: For operation above 25°C free-air or case temperature, refer to Figures 1 and 2. To avoid exceeding the design maximum virtual
junction temperature, these ratings should not be exceeded. Due to variations in individual device electrical characteristics and
thermal resistance, the built-in thermal overload protection may be activated at power levels slightly above or below the rated
dissipation.

~

::T

W
W
°C
°C
°C

to 150
-65 to 150

Storage temperature range

c

V

2
15

Operating free-air, case, or virtual junction temperature range

•..

UNIT

:=e

1800 ~

'"'""'-

0

...

os 1400
';;
1ft
is 1200
:I

0

:I
C

1000

i0

800

e

600

,~
os
::t

400

u

:I

16

2000

I
c 1600

1ft

CASE TEMPERATURE
DISSIPATION DERATING CURVE

:=
I

25

..

~

:I

" "'-

I

I

50

75

\

.r!! 10
Q

Derating factor - 16 mW/oC
R9JA '" 62.5°C/W

o

\

i.~ 12
8

.~
0
u

6

:I

4

e
e

~

I

125
100
T A - Free-Air Temperature- °c

FIGURE 1

0

:I

~

200

\.

14

c

';(

os

"

150

::t

\

\

\

Derating factor - 0.25 W/oC
above 900C
2 rRUC '" 4°C/W
I

o

I

I

75
50
100
125
Tc-Case Tempereture- °c

25

\

\
150

FIGURE 2

recommended operating conditions
uA7805C

Input voltage, VI

MAX

7

25

UNIT

uA7806C

8

25

uA7808C

10.5

25

uA7885C
uA7810C

10.5
12.5

25

uA7812C

14.5

30

uA7815C

17.5

uA7818C

21

30
33

uA7824C

27

38
1.5

A

0

125

°C

Output current, 10
Operating virtual junction temperature, TJ

2·222

MIN

TEXAS .."

INSTRUMENTS
POST OFFICE BOX 655012 • DALLAS, TEXAS 75265

28

V

uA7805C. uA7806C
POSITIVE·VOLTAGE REGULATORS
uA7805C electrical characteristics at specified virtual junction temperature, VI - 10 V, 10 - 500 rnA
(unless otherwise noted)
uA7805C

TEST CONDITIONSt

PARAMETER

25°C
Output voltage ~

10 = 5 rnA to 1 A,

VI = 7 V to 20 V,

P < 15 W
Input regulation
Ripple rejection
Output regulation
Output resistance
Temperature coefficient
01 output voltage

OOCto 125°C

VI =7 V to 25 V

TYP

4.8

5

4.75

25°C

VI = 8 V to 12 V
VI = 8 V to 18 V,

MIN

1= 120 Hz

OOCto 125°C

10 = 5 rnA to 1.5 A

62

25°C

10 = 250 rnA to 750 rnA

UNIT

5.2
5.25

3

100

1

50

V

rnV

•

dB

78
15

100

5

50

rnV

I - 1 kHz

O°C to 125°C

0.017

!l

10 = 5 rnA

OOC to 125°C

-1.1

rnVloC

...
II)

Output noise voltage

I = 10 Hz to 100 kHz

25°C

Dropout voltage

10 = 1 A

25°C

2.0

25°C

4.2

Bias current

Bias current change

MAX

VI = 7 V to 25 V

.J:.

en

V

8
1.3

O°C to 125°C

10 = 5 rnA to 1 A

CI)
CI)

~V

40

0.5

rnA

...

C

rnA

Short-circuit output current

25°C

750

rnA

Peak output current

25°C

2.2

A

CO
CO

uA 7806C electrical characteristics at specified virtual junction temperature, VI = 11 V, 10 - 500 rnA
(unless otherwise noted)
uA7806C

TEST CONDITIONst

PARAMETER

25°C
Output voltage ~

10 = 5 rnA to 1 A,

VI = 8 V to 21 V,

P:5 15 W
Input regulation
Ripple rejection

Output regulation
Output resistance
Temperature coefficient
of output voltage

OOC to 125°C

VI = B V to 25 V

TYP

MAX

5.75

6

6.25

5.7

25°C

VI =9 V to 13 V
VI-9VtoI9V,

MIN

1= 120 Hz

OOC to 125°C

10 = 5 rnA to 1.5 A

25°C

10 = 250 rnA to 750 rnA

59

6.3
5

120

1.5

60

V

rnV

dB

75
14

120

4

60

rnV

1= 1 kHz

OOC to 125°C

0.019

!l

10 = 5 rnA

OOC to 125°C

-0.8

mVloC

Output noise voltage

f = 10 Hz to 100 kHz

25°C

45

Dropout voltage

10 = 1 A

25°C

2.0

25°C

4.3

Bias current

Bias current change

UNIT

VI = 8 V to 25 V

V
8
1.3

OOC to 125°C

10=5rnAtolA

~V

0.5

rnA
rnA

Short-circuit output current

25°C

550

rnA

Peak output current

25°C

2.2

A

t Pulse testing techniques are used to maintain the junction temperature as close to the ambient temperature as possible. Thermal effects
must be taken into account separately.
::f:This specification applies only for dc power dissipation permitted by absolute maximum ratings.

TEXAS ...,
INSTRUMENTS
POST OFFICE BOX 655012 • DALLAS, TEXAS 75265

2·223

uA7BOBC, uA7BB5C
POSITIVE·VOLTAGE REGULATORS
uA7808C electrical characteristics at specified virtual junction temperature, VI ... '4 V, 10
(unless otherwise noted)

Output voltage t

•

C

Input regulation

Ripple rejection
Output regulation

Output resistance
Temperature coefficient

uA7808C

TEST CONDITIONSt

PARAMETER

10 = 5 rnA to 1 A.
P s 15 W

VI = 10.5Vto23V.

MIN

TYP

25·C

7.7

8

O·C to 125·C

7.6

VI =10.5Vto25V

6
2

25·C

VI = 11 V to 17 V
VI - 11.5 V to 21.5 V. 1- 120 Hz

O·C to 125·C

10 = 5 rnA to 1.5 A

55

25·C

80

O·Cto 125·C

4
0.016

10 = 5 rnA

O·Cto 125·C

-0.8

I = 10 Hz to 100 kHz

25·C

(/)

Dropout voltage

10 = 1 A

25·C

52
2.0

~

Bias current

25·C

4.3

O·C to 125·C

10=5rnAtolA

UNIT

V

rnV
dB

160

Output noise voltage

Bias current change

80

12

01 output voltage

!o

160

72

10 = 250 rnA to 750 rnA
I = 1 kHz

VI - 10.5 V to 25 V

MAX
8.3
8.4

I»
r+
I»

CD

= 500 mA

rnV
II
rnV'·C
/LV
V

8
1
0.5

rnA
rnA

Short-circuit output current

25·C

450

rnA

Peak output current

25·C

2.2

A

uA7885C electrical characteristics at specified virtual junction temperature, VI .. , 5 V, 10 = 500 mA
(unless otherwise noted)
TEST CONDITIONSt

PARAMETER

Output voltage t

Input regulation
Ripple rejection

Output regulation
Output resistance
Temperature coefficient

01 output voltage

10 - 5 rnA to 1 A.
P s 15 W

VI

=

MIN

11 V to 23.5 V.

25·C

8.15

O·C to 125·C

8.1

VI = 10.5 V to 25 V
VI-ll.5Vt021.5V.

I-120Hz

O·C to 125·C

10 = 5 rnA to 1.5 A

25·C

10 = 250 rnA to 750 rnA

8.5

54

170
85

70

V

rnV
dB

12

170

4

85

rnV

I = 1 kHz

O·C to 125·C

0.D16

II

10 = 5 rnA

O·C to 125·C

-0.8

rnV'·C

Output noise voltage

1= 10Hzto 100kHz

25·C

Dropout voltage

10 = 1 A

25·C

55
2.0

25·C

4.3

Bias current
Bias current change

UNIT

8.85
8.9

6
2

25·C

VI = 11 V to 17 V

uA7885C
TYP MAX

VI - 10.5 V to 25 V

V
8
1

O·Cto 125·C

10=5rnAtolA

p,V

0.5

rnA
rnA

Short-circuit output current

25·C

450

rnA

Peak output current

25·C

2.2

A

tPulse testing techniques are used to maintain the junction temperature as close to the ambient temperature as possible. Thermal effects

must be taken into account separately.
t:This specification applies only for de power dissipation permitted by absolute maximum ratings.

2·224

TEXAS

~

INSTRUMENTS
POST OFFICE BOX 655012 • DALLAS, TEXAS 75265

uA781DC, uA7812C
POSITIVE·VOLTAGE REGULATORS

uA7810C electrical characteristics at specified virtual junction temperature, VI = 17 V, 10 = 500 mA
(unless otherwise noted)
PARAMETER

Output volt_get

10

=

5 rnA to 1 A,

VI

=

12.5 V to 25 V,

P s 15 W
Input regulation
Ripple rejection
Output regulation
Output resistance
Temperature coefficient

uA7810C

TEST CONDITIONSt

VI
VI
VI

= 12.5 V to 28 V
= 14 V to 20 V
= 13 V to 23 V,

MIN

TVP

MAX

25°C

9.6

10

10.4

o·C to 125·C

9.5

10

10.5

7

200

2

100

25·C
I = 120 Hz

OoC to 125·C

10 = 5 rnA to 1.5 A
10 = 250 mA to 750 mA
1= 1 kHz
10

=

5 mA

of output voltage
Output noise voltage

1= 10Hzto 100kHz

Dropout voltage

10

=

VI
10

=
=

4
0.018

100

O·Cto 125·C
O·Cto 125·C

-1.0

1 A

2.0

25·C

4.3

5 mA to 1 A

mV

mV/·C

8
0.5

....en

Q)
Q)

.c

~V

1

O·Cto 125·C

rnV

11

70

25·C

V

dB
200

25°C

12.5 V to 28 V

71
12

Bias current
Bias current change

55

25·C

UNIT

V

til

mA

....IVIV

mA

Short-circuit output current

25·C

400

rnA

Peak output current

25°C

2.2

A

C

uA7812C electrical characteristics at specified virtual junction temperature, VI - 19 V, 10 = 500 mA
(unless otherwise noted)
PARAMETER

Output volt_get

10-5mAt01A,

VI = 14.5 V to 27 V,

P s 15W
Input regulation

Ripple rejection
Output regulation

Output resistance
Temperature coefficient
of output voltage

Output noise voltage
Dropout voltage

uA7812C

TEST CONDITIONSt

VI

=

MIN

TVP

MAX

25·C

11.5

12

12.5

O·C to 125·C

11.4

14.5 Vto 30 V

25°C

VI = 16 V to 22 V
VI -15 Vto 25 V,
10

=

1- 120 Hz

O·C to 125·C

5 mA to 1.5 A

25°C

10 = 250 mA to 750 mA
I = 1 kHz
10=5mA

= 10 Hz to
10 = 1 A

I

240

3

120

71

dB

12

240

4

120

mV

11

O·Cto 125°C

-1.0

rnV/·C

25°C

75

25·C

2.0

25°C

4.3

~V

V
B
1

O·C to 125°C

10 = 5 mA to 1 A

mV

0.Q18

100 kHz

VI- 14.5Vt030V

10

V

OOCto125·C

Bias current
Bias current change

55

12.6

UNIT

0.5

mA
mA

Short-circuit output current

25°C

350

rnA

Peak output current

25·C

2.2

A

tPulse testing techniques are used to maintain the junction temperature as close to the ambient temperature as possible. Thermal effects
must be taken into account separately.
:f:This specification applies only for dc power dissipation permitted by absolute maximum ratings.

TEXAS . "

INSTRUMENTS
POST OFFICE BOX 655012 • DALLAS, TEXAS 75265

2·225

uA7815C, uA7818C
POSITIVE·VOLTAGE REGULATORS
uA 7815C electrical characteristics at specified virtual junction temperature, VI - 23 V, 10 - 500 mA
(unless otherwise noted)

Output voltage

*

Input regulation

Ripple rejection
Output regulation
Output resistance

C

I»
r+
I»

Temperature coefficient

of output voltage

uA7815C

TEST CONDITIONSt

PARAMETER

25°C
10=5rnAto1A,
P s 15W

VI = 17.5Vto30V,

VI -17.5 V to 30 V

=

TYP

MAX

14.4

15

15.6

14.25

25°C

VI = 20 V to 26 V
VI

OOCto 125°C

MIN

18.5 V to 28.5 V, f = 120 Hz

10 = 5 rnA to 1.5 A

OOCto 125°C

54

15.75
11

300

3

150

4

!l

10 = 5 rnA

OOC to 125°C

-1.0

rnV/oC

f - 10Hzto 100kHz

25°C

90

10 = 1 A

25°C

2.0

::T

Bias current

25°C

4.4

Bias current change

rnV

0.019

Dropout voltage

til

300
150

OOC to 125°C

Output noise voltage

r+

rnV

10 - 250 rnA to 750 rnA
1 = 1 kHz

CJ)

CD
CD

V

dB

70
12

25°C

UNIT

VI = 17.5Vt030V
10 = 5 rnA to 1 A

O°C to 125°C

Short-circuit output current

25°C

Peak output current

25°C

~V

V
8
1
0.5

230
2.1

rnA
rnA
rnA
A

uA7818C electrical characteristics at specified virtual junction temperature, VI = 27 V, 10 - 500 mA
(unless otherwise noted)

Output voltage

*

10

=

5 rnA to 1 A,

VI

=

21 V to 33 V.

P s 15 W
Input regulation

VI = 21 V to 33 V
VI =24Vto30V

Ripple rejection

VI =22Vt032V.

Output regulation
Output resistance
Temperature coefficient

01 output voltage

uA7818C

TEST CONDITIONst

PARAMETER

MIN

TYP

MAX

25°C

17.3

18

18.7

OOCto 125°C

17.1

=

120 Hz

OOC to 125°C

10 = 5 rnA to 1.5 A

25°C

10 - 250 rnA to 750 rnA
f = 1 kHz
10

=

=

5 rnA

Output noise voltage

1

Dropout voltage

10 - 1 A

69
12
4

360
180

rnV

360
180

rnV

dB

0.022

!l

OOC to 125°C

-1.0

rnV/oC

10Hzto 100kHz

VI = 21 V to 33 V
10 - 5 rnA to 1 A

53

V

OOC to 125°C

Bias current
Bias current change

15
5

25°C
1

18.9

UNIT

25°C

110

25°C

2.0

25°C

4.5

OOCt0125°C

Short-circuit output current

25°C
25°C

Peak output current

~V

V
8
1
0.5

200
2.1

rnA
rnA
rnA
A

tPulse testing techniques are used to maintain the junction temperature as close to the ambient temperature as possible. Thermal effects

must be taken into account separately.
tThis specification applies only for dc power dissipation permitted by absolute maximum ratings.

2-226

TEXAS . "

INSTRUMENTS
POST OFFICE BOX 655012 • DALLAS. TeXAs 75265

uA7824C
POSITIVE·VOLTAGE REGULATOR

uA7824C electrical characteristics at specified virtual junction temperature. VI
(unless otherwise noted)

Output voltage

*

25°C

10

~

5 mA to 1 A,

VI

~

27 V to 38 V,

p" 15W
Input regulation

Output regulation

10
10

Output resistance

f

of output voltage

~
~

10

Output noise voltage

f

Dropout voltage

10

f - 120 Hz

~

DoC to 125°C

5 mA to 1.5 A

25°C

250 mA to 750 mA
1 kHz

~

~

Short~circuit

MAX

24

25

22.8

5 mA

18

480

6

240

66

V

mV

II

dB

12

480

4

240

mV
II

DoC to 125°C

-1.5

mV/oC

1 A

VI - 27 V to 38 V
10 ~ 5 mA to 1 A

50

25.2

UNIT

0.028

Bias current
Bias current change

TYP

23

500 rnA

DoC to 125°C

10 Hz to 100 kHz

~

MIN

25°C

VI ~3OVt036V
VI -28Vt038V,

Temperature coefficient

DoC to 125°C

VI ~ 27 V to 38 V

Ripple rejection

=

uA7824C

TEST CONDITIONSt

PARAMETER

33V.IO

25°C

170

25°C

2.0

25°C

4.6

Peak output current

V
8
1

aOCto 125°C

output current

~V

0.5

mA
mA

25°C

150

mA

25°C

2.1

A

tPulse testing techniques are used to maintain the junction temperature as close to the ambient temperature as possible. Thermal effects

must be taken into account separately.
*This specification applies only for de power dissipation permitted by absolute maximum ratings.

TEXAS ..,
INSTRUMENTS
POST OFFICE BOX 655012 • DALLAS, TEXAS 75265

2-227

C

D.I
r+
D.I

en

:T
CD
CD
r+

UI

2-228

SERIES uA78LOO
POSITIVE-VOLTAGE REGULATORS
02203, JANUARY 1976-REVISED FEBRUARY 1988

•

3-Terminal Regulators

•

Output Current Up to 100 mA

•

No External Components

•

Internal Thermal Overload Protection

•

Internal Short-Circuit Limiting

•

Direct Replacement for Fairchild p.A 78LOO
Series

NOMINAL

5%

10%

OUTPUT

OUTPUT VOLTAGE

OUTPUT VOLTAGE

VOLTAGE

TOLERANCE

TOLERANCE

2.6 V

uA78L02AC

uA78L02C

5V

uA78L05AC

uA78L05C

6.2 V

UA78L06AC

uA78L06C

8V

uA78L08AC

uA78L08C
uA78L09C

9V

uA78L09AC

10V

uA78L10AC

uA78L10C

12 V

uA78L12AC

uA78L12C

15 V

uA78L15AC

uA78L15C

JG

D
"SMALL OUTLINE" PACKAGE

DUAL-IN-LiNE PACKAGE

(TOP VIEW)

(TOP VIEWI

OUTPUT
COMMON
COMMON
NC

D
2
3
4

7
6
5

)NPUT
COMMON
COMMON
NC

NC
ON,,"'
NC
NC

DO""""
2
3
4

7
6
5

NC
COMMON
NC

II
...

LP
SILECT PACKAGE

CI
,

II)

Q)
Q)

(TOP VIEW)

.c

en

;;

ON,,"'
COMMON

o

OUTPUT

...

1'0
1'0

C

TO-226AA

•

~

OCI

NC- No Internal connection

description
This series of fixed-voltage monolithic integrated-circuit voltage regulators is designed for a wide range
of applications. These applications include on-card regulation for elimination of noise and distribution
problems associated with single-point regulation. In addition. they can be used with power-pass elements
to make high-current voltage regulators. One of these regulators can deliver up to 100 mA of output current.
The internal limiting and thermal shutdown features of these regulators make them essentially immune
to overload. When used as a replacement for a Zener diode-resistor combination. an effective improvement
in output impedance can be obtained together with lower-bias current.

PRODUCTION DATA doc.mantl .ontlin infarmatian
eumat I. of publication data. Praducts canfarm to
specifications par the tar.. of TIXIS 'I.truments

:~~=:=i~ai~:I:ri ~=:~:r :.r:::~~:.-

not

Copyright © 1977. Texas Instruments Incorporated

TEXAS •

INSTRUMENTS
POST OFFICE BOX 655012 • DALLAS. TeXAS 75265

2-229

SERIES uA78LOO
POSITIVE·VOLTAGE REGULATORS
schematic
.----.~----------------------------~~--------e_----~e_----._-INPUT

20 kll

c

~----4-------4-~--~----~--~--OUTPUT

I\)

r+

I\)

1 kll TO 14 kll

en
:::r
CD
CD

r+

III

1.4 kll

~--------~~~------~----~--~~--------~~----------~-----COMMON

Resistor values shown are nominal.

2-230

TEXAS ."

INSfRUMENlS
POST OFFICE BOX 655012 • DALLAS, TEXAS 75265

SERIES uA78LOO
POSITIVE·VOLTAGE REGULATORS
absolute maximum ratings over operating temperature range (unless otherwise noted)
uA78L02AC,uA78L02C

uA78L12AC, uA78L12C

THRU

uA78L15AC,uA78L15C

uA78Ll0AC, uA78L10C
Input voltage

35
30
See Dissipation Rating Tables 1 and 2
o to 150
Oto150
I

Continuous total dissipation (see Note 1)
Operating free-air, case, or virtual junction temperature range

Storage temperature range

I
I

-65 to 150

Lead temperature 1,6 mm (1/16 inch) from case for 10 seconds

260

UNIT
V
°C

-65 to 150

°C

260

°C

NOTE 1: To avoid exceeding the design maximum virtual junction temperature, these ratings should not be exceeded. Due to variations
in individual device electrical characteristics and thermal resistance, the built-in thermal overload protection may be activated
at power levals slightly above or below the rated dissipation.

DERATE

II
...
U)

DISSIPATION RATING TABLE 1 - FREE-AIR TEMPERATURE

Q)
Q)

PACKAGE

TA '" 25°C
POWER RATING

DERATING
FACTOR

A80VE TA

TA - 70°C
POWER RATING

D

825 mW

25°C

464 mW

til

JG
LPt

825 mW
775 mW

5.8 mW/oC
6.6 mW/oC
6.2 mW/oC

25°C
25°C

528 mW
496 mW

~

.c

...
~

o

tThe LP package dissipation rating is based on thermal resistance R6JA measured in still
air with the device mounted in an Augat socket. The bottom of the package was 10 mm
(0.375 in) above the socket.

DISSIPATION RATING TABLE 2 - CASE TEMPERATURE
PACKAGE

TC '" 25°C
POWER RATING

JG

D

1600 mW
1600 mW

LP

1600 mW

DERATING

DERATE

FACTOR
19.6 mW/oC

ABOVE TC
65°C

17.2 mW/oC

57°C

490 mW
430 mW

28.6 mW/oC

94°C

715mW

TC - 125°C
POWER RATING

recommended operating conditions
MIN
4.75

MAX
20

uA78L05C, uA78L05AC

7

20

uA78L06C, uA78L06AC

8.5

20

uA78L08C,uA78L08AC
uA78L09C, uA78L09AC

10.5
11.5

23
24

uA78Ll0C, uA78Ll0AC

12.5

25

uA78L12C, uA78L12AC

14.5

27

uA78L15C,uA78L15AC

17.5

30

uA78L02C, uA78L02AC

Input voltage, VI

Output current, 10
Operating virtual junction temperature, T J

0

TEXAS •

INSfRUMENTS
POST OFFICE BOX 655012 • DALLAS, TEXAS 75265

UNIT

V

100

mA

125

°C

2·231

SERIES uA78LOO
POSITIVE·VOLTAGE REGULATORS
uA78L02AC. uA78L02C electrical characteristics at specified virtual junction temperature. VI = 9 V.
10 - 40 rnA (unless otherwise noted)

Output voltage *

Input regulation

Ripple rejection
Output regulation

Output noise voltage

C

Dropout voltage

r+

Bias current

VI- 4.75Vt020V,10

~

1 rnA to 40 rnA

10 - 1 rnA to 70 rnA
VI ~ 4.75 V to 20 V
VI

~

5 V to 20 V

VI

~

6 V to 16 V, f

en
'::r'
CD
CD

r+

III

Bias current change

25°C
OOC to
125°C

~

120 Hz

10 - 1 rnA to 100 rnA
10 ~ 1 rnA to 40 rnA
f ~ 10 Hz to 100 kHz

25°C

uA78L02C

MIN

TYP

MAX

MIN

TYP

MAX

2.5

2.6

2.7

2.4

2.6

2.8

2.75
2.75

2.35
2.35

2.45
2.45

25°C
43

2.85
2.85

20

100

20

125

16

75

16

100

51

42

51

50

12

50

6
30

25

6
30

25

25°C
25°C

1.7

25°C

3.6

VI

~

5 V to 20 V

125°C
OOC to

10

~

1 rnA to 40 rnA

125°C

V

rnV

rnV
pV

1.7
6

UNIT

dB

12

25°C

Dl
Dl

uA78L02AC

TEST CONDITIONS t

PARAMETER

V

3.6

6

5.5

5.5

2.5
0.1

0.2

2.5

rnA
rnA

uA78L05AC. uA78L05C electrical characteristics at specified virtual junction temperature. VI ... 10 V.
10 - 40 rnA (unless otherwise noted)
uA78L05AC

TEST CONDITIONst

PARAMETER

25°C
Output voltage*

VI
10

~
~

7 V to 20 V, 10 ~ 1 rnA to 40 rnA
1 rnA to 70 rnA

aoe to
125°C

Input regulation

VI - 7 V to 20 V
VI ~ B V to 20 V

25°C

Ripple rejection

VI = 8 V to lB V, f = 120 Hz

25°C

Output regulation

10 = 1 rnA to 100 rnA
10 - 1 rnA to 40 rnA

TYP

MAX

MIN

TYP

MAX

4.B

5

5.2

4.6

5

5.4

5.25
5.25

4.5
4.5

4.75
4.75
32
26
41

25°C

40

15

60
30

25°C

B
42

Dropout voltage

25°C

1.7

25°C

3.B

Bias current change

150
100

49

Output noise voltage f = 10 Hz to 100 kHz

Bias current

uA78L05C

MIN

5.5
5.5
32

200

26

150

49
60

B

30

3.B

V

rnV
dB

15

rnV
pV

42
1.7
6

UNIT

V
6

125°C
OOC to

5.5

VI - B V to 20 V

1.5

5.5
1.5

10 = 1 rnA to 40 rnA

125°C

0.1

0.2

rnA
rnA

tPulse testing techniques are used to maintain the junction temperature as close to the ambient temperature as possible. Thermal effects
must be taken into account separately. All characteristics are measured with a O.33-~F capacitor across the input and a O.l-jlF capacitor
across the output.
tThis specification applies only for de power dissipation permitted by absolute maximum ratings.

2-232

TEXAS

~

INSTRUMENTS
POST OFFICE BOX 655012 • DALLAS, TEXAS 75265

SERIES uA78LOO
POSITIVE-VOLTAGE REGULATORS
12 V.

uA 78L06AC. uA 78L06C electrical characteristics at specified virtual junction temperature. VI
10 = 40 mA (unless otherwise noted)

Output voltage;

Input regulation
Ripple rejection
Output regulation

Output noise voltage

uA7BL06AC

TEST CONOITIONst

PARAMETER

TYP

MAX

MIN

TYP

MAX

6.2

6.2

6.7

25°C
OOC to

5.95

6.45

5.7

VI = 8.5 V to 20 V, 10 = 1 rnA to 40 rnA

5.9

6.5

5.6

6.B

10 = 1 mA to 70 mA

125°C

5.9

6.5

5.6

6.B

VI = B.5 V to 20 V

= 9 V to 20 V
VI = 10Vt020V,f =
10 = 1 mA to 100 mA
10 = 1 mA to 40 rnA
f = 10 Hz to 100 kHz

25°C

VI

120 Hz

25°C

Bias current

VI
10

=
=

35

175

35

200

29

125

29

150

4B

40

25°C

Dropout voltage

Bias current change

uA7BL06C

MIN

39

16

BO

9

40

4B

Output voltage:t:

80

9

40

46

~V

25°C

1.7

1.7

V

25°C

3.9

6

3.9

6

5.5

5.5

1.5

1.5

1 mA to 40 mA

125°C

0.1

0.2

10
Input regulation

Ripple rejection
Output regulation

VI
VI
VI
10

=
=
=
=
=

1 mA to 70 mA
10.5 V to 23 V
13Vt023V,f

=

10 Hz to 100 kHz

Bias current

VI - 11 V to 23 V
10

=

=

1 mA to 100 mA

1 mAto 40 mA

120 Hz

uA7BLOBC

TYP

MAX

MIN

TYP

MAX

7.7

B

B

8.64

25°C
ooe to

8.3

7.36

7.6

8.4

7.2

8.8

125°C

7.6

8.4

7.2

8.8

25°C

37

42

175

42

200

36

125

36

150

46

25°C

36

18

80

10

40

46
80

10

40

54

54

25°C

1.7

1.7

25°C

4

6

4

mA

en

mA

...

CI:I
CI:I

C

UNIT

V

mV
dB

18

25°C

en

Q)
Q)
~

14V.

MIN

25°C

11 V to 23 V

10 - 1 mA to 40 mA

Output noise voltage f
Dropout voltage

Bias current change

uA7BLOBAC

TEST CONDITIONst

II
...

mV

46

125°C
OOC to

= 1 rnA to 40 rnA

mV

25°C

9 V to 20 V

VI = 10.5 V to 23 V, 10

V

dB

16

uA 78L08AC. uA78L08C electrical characteristics at specified virtual junction temperature. VI
10 = 40 mA (unless otherwise noted)
PARAMETER

UNIT

mV
~V

V
6

125°C
OOC to

5.5
1.5

5.5
1.5

125°C

0.1

0.2

mA
mA

tPulse testing techniques are used to maintain the junction temperature as close to the ambient temperature as possible. Thermal effects
must be taken into account separately. All characteristics are measured with a O.33-p.F capacitor across the input and a 0. l-"F capacitor
across the output.
~This specification applies only for dc power dissipation permitted by absolute maximum ratings.

TEXAS

~

INSTRUMENTS
POST OFFICE BOX 655012. DALLAS, TEXAS 75265

2-233

SERIES uA78LOO
POSITIVE·VOLTAGE REGULATORS
~

uA78L09AC. uA78L09C electrical characteristics at specified virtual junction temperature. VI
10 - 40 mA (unless otherwise noted)
PARAMETER

uA78L09AC

TEST CONOITIONSt
25°C

Output voltage'

= 12 V to 24 V, 10 = 1 mA to 40 mA
= 1 mA to 70 mA
VI = 12 V to 24 V
VI = 13 V to 24 V
VI = 15 V to 25 V, f = 120 Hz
10 = 1 mAto 100mA
10 = 1 mA to 40 mA
f = 10Hz to 100 kHz
VI

10

Input regulation

E,
c
C»

1+

C»

en

::r

CD
CD

1+

en

Ripple rejection
Output regulation

Output noise voltage
Dropout voltage

Bias ·current
Bias current change

VI
10

=
=

O°C to
125°C

TYP

MAX

MIN

TYP

MAX

8.6

9

9.4

8.3

9

9.7

8.55

9.45

8.1

9.9

8.55

9.45

8.1

9.9

25°C
25°C

uA78L09C

MIN

38

45

175

45

225

40

125

40

175

45

25°C

36

19

90

11

40

45
90

11

40

58

58

25°C

1.7

1.7

25°C

4.1

125°C

5.5

13Vt024V

OOC to

1.5

1.5

1 mA to 40 mA

125°C

0.1

0.2

5.5

Output vOltage+

Input regulation
Ripple rejection
Output regulation

uA78L10C

TYP

MAX

MIN

TYP

MAX

9.6

10

10.4

9.2

10

10.8

VI = 13Vt025V,IO = 1 mAt040mA

25°C
OOC to

9.5

10.5

9

11

10 - 1 mA to 70 mA

125°C

9.5

10.5

9

11

=
=
=

VI
VI
VI

13 V to 25 V

25°C

14 V to 25 V

=

15 V to 25 V, f

10 - 1 mA to 100 mA

= 1 mA to 40 mA
= 10 Hz to 100 kHz

10

Bias current

VI
10

=
=

120 Hz

25°C

37

51

175

51

225

42

125

42

175

44

25°C

36

20

90

11

40

44
90

11

40

62

62

25°C

1.7

1.7

25°C

4.2

6

4.2

mA
mA

UNIT

V

mV
dB

20

25°C

mV

-= 17 V.

MIN

Output noise voltage f
Dropout voltage

Bias current change

uA78L10AC

TEST CONDITIONst

mV

V
6

uA78L 10AC. uA78L 10C electrical characteristics at specified virtual junction temperature. VI
10 - 40 mA (unless otherwise noted)
PARAMETER

V

~V

4.1

6

UNIT

dB

19

25°C

16 V.

mV
~V

V
6

125°C
OOC to

5.5

14 V to 25 V

1.5

5.5
1.5

1 mA to 40 mA

125°C

0.1

0.2

mA
mA

tPulse testing techniques are used to maintain the junction temperature as close to the ambient temperature as possible. Thermal effects
must be taken into account separately. All characteristics are measured with a O.33-I'F capacitor across the input and a O.1-IlF capacitor
across the output.
:t:This specification applies only for dc power dissipation permitted by absolute maximum ratings.

2-234

TEXAS ~
INSTRUMENTS
POST OFFICE BOX 655012 • DALLAS. TEXAS 75265

SERIES uA78LOO
POSITIVE-VOLTAGE REGULATORS
uA78L 12AC. uA78L 12C electrical characteristics at specified virtual junction temperature. VI .. 19 V.
10 .. 40 mA (unless otherwise noted)
PARAMETER

Output voltage t

Input regulation
Ripple rejection
Output regulation

Output noise voltage

uA78L12AC

TEST CONDITIONSt

TYP

MAX

MIN

TYP

MAX

11.5

12

12.5

11.1

12

12.9

VI = 14 V to 27 V. 10 = 1 rnA to 40 rnA

25°C
OOC to

11.4

12.6

10.8

13.2

10 = 1 rnA to 70 mA

125°C

11.4

12.6

10.8

13.2

VI = 14.5 V to 27 V

=

VI

25°C

16 V to 27 V

VI - 15 V to 25 V. f - 120 Hz

25°C

= 1 mAto 100mA
10 = 1 mA to 40 mA
f = 10 Hz to 100kHz
10

Bias current
VI
10

=
=

37

25°C

Dropout voltage

Bias current change

uA78L12C

MIN

55

250

55

250

49

200

49

200

42

36

22

100

13

50

42

Output voltage t

Input regulation

100

13

50

70

pV

25°C

1.7

1.7

V

25°C

4.3

4.3

6.5

6.5

6

6

16 V to 27 V

125°C
OOC to

1.5

1.5

1 mA to 40 mA

125°C

0.1

0.2

Ripple rejection

Output regulation

uA78L 15C

TYP

MAX

MIN

TYP

MAX

14.4

15

15.6

13.8

15

16.2

VI = 17.5Vt030V.10 -1 rnAt040mA

14.25

15.75

13.5

16.5

10 - 1 mA to 70 mA

125°C

14.25

15.75

13.5

16.5

VI
10

= 17.5Vt030V
= 20 V to 30 V
= 18.5 V to 28.5 V. f =
= 1 mA to 100 mA

10 - 1 mA to 40 rnA

Output noise voltage f
Dropout voltage

=

10Hzto 100kHz

Bias current
Bias current change

uA78L15AC
MIN

VI
10

=
=

25°C
120 Hz

25°C

34

25°C

65

300

65

300

58

250

58

250

39

33

25

150

15

75

39
150

15

75

82

82

25°C

1.7

1.7

25°C

4.6

6.5

4.6

II)

Q)
Q)

mA

.r::.

CI)

mA

23V.

...
CO
CO

Q

UNIT

V

mV
dB

25

25°C

fI
...

mV

70

25°C
OOC to

VI

mV

25°C

TEST CONDITIONSt

VI

V

dB

22

uA78L 15AC. uA78L 15C electrical characteristics at specified virtual junction temperature. VI
10 = 40 mA (unless otherwise noted)
PARAMETER

UNIT

mV
pV
V

6.5

125°C
OOC to

6

6

10 V to 30 V

1.5

1.5

1 mAto 40 mA

125°C

0.1

0.2

mA
mA

tPulse testing techniques are used to maintain the junction temperature as close to the ambient temperature as possible. Thermal effects
must be taken into account separately. All characteristics are measured with a O.33-p.F capacitor across the input and a O.1-p.F capacitor
across the output.
tThis specification applies only for dc power dissipation permitted by absolute maximum ratings.

TEXAS . "

INSTRUMENTS
POST OFFICE BOX 655012. DALLAS, TeXAS 75265

2-235

•

c

Q)

r+
Q)

CJ)
';:
CD
CD
r+

til

2-236

SERIES uA78MOO
POSITIVE-VOLTAGE REGULATORS
02214, JUNE 1976-REVISED APRIL 1988

•
•
•

•
•
•
•
•

3-Terminal Regulators
Output Current Up to 500 mA

NOMINAL

-55°C TO 150°C

ooC TO 125°C

OUTPUT

OPERATING

OPERATING

VOLTAGE

No External Components

TEMPERATURE RANGE TEMPERATURE RANGE

5V

uA7BM05M

BV

Internal Thermal Overload Protection
High Power Dissipation Capability

Output Transistor Safe-Aree Compensation

uA7BMOSC

BV

uA7BMOBC

9V

uA7BM09C

10

Internal Short-Circuit Current Limiting

v

uA7BM10C

12 V

uA7BM12M

uA7BM12C

15 V

uA7BM15M

uA7BM15C

24 V

uA7BM24C

PACKAGES

description
This series of fixed-voltage monolithic
integrated-circuit voltage regulators is designed
for a wide range of applications. These
applications include on-card regulation for
elimination of poise and distribution problems
associated with single-point regulation. Each of
these regulators can deliver up to 500 mA of
output current. The internal current limiting and
thermal shutdown features of these regulators
make them essentially immune to overload. In
addition to use as fixed-voltage regulators. these
devices can be used with external components
to obtain adjustable output voltages and currents
and also as the power pass element in precision
regulators.

terminal assignments

II
....

uA7BM20C

20 V

Direct Replacements for Fairchild ,.A78MOO
Series

uA7BM05C

JG

KC

en

schematic

Q)
Q)

140

..c
en

INPUT

kll

....COCO

C

O.S II
OUTPUT

Resistor values shown are nominal.
uA78M_M •.. JG PACKAGE

uA78M_C •.. KC PACKAGE

(TOP VIEW)

(TOP VIEW)

~'D~
NC

2

7

NC

NC

3

6

OUTPUT

INPUT

4

5

NC

rl

~

THE COMMON TERMINAL IS IN
ELECTRICAL CONTACT WITH
THE MOUNTING BASE
TO·220AB

NC - No internal connection.

~'

--

PRODUCTION DATA documonts CDnllin inl1l,m.ti.n
current as of publication data. Products confarm to
specificatiDDI par the terms of Taxas Instruments

::==i~·t::1~1i ~::~:;ti~n l!~":::::.t\::~

not

OUTPUT
COMMON
INPUT

TEXAS

~

INSTRUMENTS
POST OFFICE BOX 656012 • OALLAS, TEXAS 75265

CopYright @ 1983, Texas Instruments Incorporated

2-237

SERIES uA78MOO
POSITIVE·VOLTAGE REGULATORS

absolute maximum ratings over operating temperature range (unless otherwise noted)

I

Input voltage

free~air,

35

35

UNIT

V

See Dissipation Rating Tables 1 and 2

I JG

Lead temperature 1,6 mm 11/1 6 inch) from case for 60 seconds
Lead temperature 1. 6 mm 11/16 inch) from case for 10 seconds

o to 150
-65 to 150

-55 to 150
-65 to 150
300

case or virtual junction temperature range

Storage temperature range

E

uA7BM05C
THRU
uA7BM24C
-40

uA78M20, uA78M24

I All others

Continuous total dissipation Isee Note ,)
Operating

uA7BM05M
uA7BM12M
uA7BM15M

package

1 KC package

260

°C
°C
°C
°C

c

NOTE 1: To avoid exceeding the design maximum virtual junction temperature, these ratings should not be exceeded. Due to variations
in individual device electrical characteristics and thermal resistance, the built-in thermal overload protection may be activated
at power levels slightly above or below the rated dissipation.

D)

DISSIPATION RATING TABLE I-fREE-AIR TEMPERATURE

...
D)

en
:r

PACKAGE

...
CD
CD

JG
KC

(/I

TA s 25°C
POWER RATING
1050 mW
2000 mW

DERATING fACTOR
ABOVE TA - 25°C
8.4 mW/oC
16 mW/oC

TA - 70°C
POWER RATING
672 mW
1280 mW

DISSIPATION RATING TABLE 2-CASE TEMPERATURE
PACKAGE
KC

TC S 5O·C
POWER RATING
20W

DERATING fACTOR
ABOVE TC - 50·C
200 mW/oC

TC - 125·C
POWER RATING
5W

recommended operating conditions
uA78M05M, uA78M05C

Input voltage, VI

Output current, 10
Operating virtual junction temperature, TJ

2-238

I
I

uA78M06C
uA78MOBC
uA78M09C
uA78Ml0C
uA78M12M, uA78M12C
uA78M15M, uA78M15C
uA78M20C
uA78M24C
All devices
uA7BM05M thru uA78M15M

I uA78M05C thru uA78M24C

TEXAS •

INSTRUMENlS
POST OFFICE BOX 866012 • DALLAS, TEXAS 75265

MIN
7
8
10.5
11.5
12.5
14.5
17.5
23
27
-55
0

MAX
25
25
26
26
28
30
30
35
38
500
150
125

UNIT

V

mA
°C

uA78M05M, uA 78M05C electrical characteristics at specified virtual junction temperature, VI - 10 V, 10
otherwise noted)

Output voltage~

Input regulation

Ripple rejection

~

Output regulation

~i:iZ

Temperature coefficient

~

~~

;;c~~

g:~c:

~~

Ftr'J

of output voltage
Output noise voltage

=

5 mA to 350 mA

10

=

200 mA

VI
f

= BVto
= 120 Hz

10
10

=
=

5 mA to 500 mA
5mAto200mA

10

=

5mA

f

=

10

=

10

= 300

10

=

200 mA, VI

Peak output current

mA

V
V
V
V
V

25°C
- 55°C to 150°C
OOC to 125°C

MIN

TYP

MAX

MIN

TYP

MAX

4.B
4.7

5

5.2
5.3

4.B

5

5.2

3

5.25
100

1

50

3
1

25°C
-55°C to 150°C
O°C to 125°C
25°C

= B V to

10

=

5 mA to 350 mA

VI

=

35 V

50
25

mV

62
62

25°C

25 V

UNIT

V
4.75

80
20
10

-55°C to 25°C
25°C to 150°C
OOC to 125°C

Bias current change

output current

20
20
25
20
25

100 mA

Bias current

Short-circuit

~

= B V to
= 7 V to
= 7 V to
= B V to
= B V to

10Hzto 100kHz

~

'"'"

lBV,

VI
VI
VI
VI
VI

Dropout voltage

~Z

~~4r

10

uA78M05C

uA78M05M

TEST CONDITIONSt

PARAMETER

= 350 mA (unless

62
62
50
25
-2
-1.5

dB

BO
20
10

100
50

mV

mV/oC
-1
40
2
4.5

~V

40
2
4.5

25°C

300

600

300

mA

0.7

1.4

0.7

A

25°C

200
2.5
7
O.B

200
2.5
6

25°C
25°C
25°C
-55°C to 150°C
OOC to 125°C
- 55°C to 150°C
O°Cto 125°C

O.B
0.5

V
mA

mA

0.5

0.5

tPulse testing techniques are used to maintain the junction temperature as close to the ambient temperature as possible. Thermal effects must be taken into account separately.
tThis specification applies only for dc power dissipation permitted by absolute maximum ratings.

-a
CI
en

:::j

;:
rn

'I:

<;a:.
CI"""
r-=

;:B
Ci)c:I
rnUl

:::ajl
rn

Ci)1:

c:;a:.

-4.=

r-"""
;a:.

Clc:I

i')

~

W

(D

Data Sheets

II

:::a UI
enn

uA78M06C, uA78M06C
POSITIVE·VOLTAGE REGULATORS
uA78M06C electrical characteristics at specified virtual junction temperature. VI .. 11 V.
10 ... 350 mA (unless otherwise noted)
PARAMETER

Output voltage

*

Input regulation
Ripple rejection

•

C

Output regulation
Temperature coefficient

01 output voltage

10 = 5 mA to 350 mA

VI = BVt021 V

10 = 200 mA

VI = B V to 25 V
VI = 9 V to 25 V

10 = 100 mA
10 = 300 mA

VI = 9 V to 19 V,
f=120Hz

25°C
OOeto 125°C

MIN

TYP

MAX

5.75

6

6.25

5
1.5

100
50

5.7

25°C
OOet0125°e

59

25°C

59

10 = 5 mA to 500 mA
10 = 5 mA to 200 mA

25°C

10 = 5mA

6.3

20

120

10

60

p.V

2

Bias current

25·e

4.5

Bias current change

Short-circuit
output current

f - 10 Hz to 100 kHz

10 = 200 mA,
10 - 5 mA to 350 mA

VI = 9 V to 25 V

V

o·eto 125·e

6
O.B

o·e to 125·e

0.5

VI = 35 V

Peak output current

Output voltage*
Input regulation
Ripple rejection
Output regulation

Temperature coefficient

01 output voltage
Output noise voltage

= 10.5 Vto 23 V
= 10.5 V to 25 V

270

mA

0.7

A

MIN

TYP

MAX

25·e

7.7

B

B.3

o·eto 125·e

7.6
6

B.4
100

2

50

25·e

= 11 V to 25 V
= 100 mA

- 300 mA

o·eto 125·e
25·e
25·e

10 = 5 mA

Short-circuit
output current

10 = 200 mA,
VI = 10.5 V to 25 V
10 - 5 mA to 350 mA

56

UNIT

V
mV
dB

BO
25

160

10

BO

mV

-1

mv/·e

25·e

52

p.V

25·e

2

Dropout voltage

Bias current change

56

14 V.

o·eto 125·e

1 = 10 Hz to 100 kHz

Bias current

mA

25·e

TEST CONDITIONst

10 = 5 mA to 350 mA VI
VI
10 = 200 mA
VI
VI = 11.5 V to 21.5 V, 10
1 = 120 Hz
10
10 = 5 mA to 500 mA
10 = 5 mAto200 mA

mA

25·e

uA78M08C electrical characteristics at specified virtual junction temperature. VI
10 = 350 mA (unless otherwise noted)
PARAMETER

mV
mv/oe

45

::T
CD
CD

mV

-1

25·e

(f)

V

OOeto 125°C
25·e

Output noise voltage

UNIT

dB

BO

Dropout vottage

...mm
...en

TEST CONDITIONSt

25·e
o·e to 125·e

4.6

o·eto 125·e

VI = 35 V

Peak output current

V
6
O.B
0.5

mA
mA

25·e

250

mA

25·e

0.7

A

tPulse testing techniques are used to maintain the junction temperature as close to the ambient temperature as possible. Thermal effects
must be taken into account separately.
:l:This specification applies only for de power dissipation permitted by absolute maximum ratings.

2-240

TEXAS ."

INSTRUMENTS
POST OFFICE BOX 655012 • DAllAS. TEXAS 75265

uA78M09C, uA78M10C
POSITIVE-VOLTAGE REGULATORS
uA 78M09C electrical characteristics at specified virtual junction temperature. VI
(unless otherwise noted)
PARAMETER

Output voltage t
Input regulation

Ripple rejection
Output regulation
Temperature coefficient

TEST CONDITIONST

10 - 5 rnA to 350 rnA

=

10

200 rnA

= 13Vto23V,
= 120 Hz

VI
f

VI - 11.5 V to 24 V
VI = 11.5 Vto 26 V
VI = 12 V to 26 V
10 = 100 rnA
10 - 300 rnA

25°C
OOCtoI25°C

=

5 rnA to 200 rnA

10

=

5 rnA

16 V. 10 - 350 mA

MIN

TYP

MAX

B.6

9
6

9.4
9.5
100

2

50

B.5

25°C
OOC to 125°C

56

25°C

56

10 - 5 rnA to 500 rnA
10

=

25°C

UNIT

V
rnV
dB

BO
25

180

10

90

rnV

OOC to 125°C

-1

rnV/oC

25°C

58

~V

Dropout voltage

25°C

2

Bias current

25°C

4.6

of output voltage
Output noise voltage

Bias current change
Short~circuit

output current

f - 10Hzto 100kHz

10
10

=
=

200 rnA,
5 rnA to 350 rnA

VI

=

35 V

VI

=

11.5 V to 26 V

OOCto 125°C

Peak output current

0.5

rnA

25°C

0.7

A

Output voltage t
Input regulation
Ripple rejection
Output regulation
Temperature coefficient

of output voltage
Output noise voltage

10
10

=
=

5 rnA to 350 rnA
200 rnA

= 15 V to 25 V,
= 120 Hz
10 = 5 rnA to 500 rnA
10 = 5 rnA to 200 rnA

VI
f

10
f

=

=

VI = 12.5 V to 25 V
VI = 12.5 V to 28 V
VI - 14Vto28V
10 = 100 rnA
10 = 300 rnA

25°C
OOC to 125°C

25°C
25°C

5 rnA

Short-circuit
output current

VI

200 rnA

10

=

5 rnA to 350 rnA

VI

=

35 V

VI

=
=

13.5 Vto 28 V
12.5 V to 28 V

59
55

10.5
7

100

C

2

50

80
25

200

10

100

V
rnV
d8
rnV

25°C

64

~V

25°C
25°C

2
4.7

6

OOCto 125°C

0.8

OOCto 125°C

0.5

Peak output current

...caca

UNIT

rnV/oC

Bias current

=

10.4

-1

10 Hz to 100 kHz

10

MAX

10

OOCto 125°C

Dropout voltage

Bias current change

TYP

9.6

25°C
OOCto 125°C

(/)

17 V.

MIN

9.5

.s::.

rnA

250

TEST CONDITIONSt

Q)
Q)

rnA

25°C

uA78M10C electrical characteristics at specified virtual junction temperature. VI
10 = 350 mA (unless otherwise noted)
PARAMETER

fI)

V
6
0.8

II
...

V
rnA
rnA

25°C

245

rnA

25°C

0.7

A

tPulse testing techniques are used to maintain the junction temperature as close to the ambient temperature as possible. Thermal
effects must be taken into account separately.
tThis specification applies only for dc power dissipation permitted by absolute maximum ratings.

TEXAS •

INSTRUMENTS
POST OFFICE BOX 655012 • DALLAS, TEXAS 75265

2-241

s~aa4S e~ea

N

N

"""

II

.,,=

N

uA78M 12M. uA78M 12C electrical characteristics at specified virtual junction temperature. VI
otherwise noted)

Output voltage ~

10

=

5 mA to 350 mA

VI
VI

=
=

25°C
-55°C to 150°C

15.5 V to 27 V
14.5 V to 27 V

MIN

TYP

11.5

12

10 = 200 mA

MAX
12.5

O°C to 125°C
8
2

25°C

VI = 16 V to 25 V

MIN

TYP

MAX

11.5

12

12.5

60

8

Ripple rejection

~

o
'll_

Output regulation

i:jZ

Temperature coefficient

!~

of output voltage

;C~d

VI = 15Vto25V,
f

=

120 Hz

=

100mA

10

=

300 mA

25°C

5mAto500mA

10 10

10

=

55

25°C

5mAto200mA

=

d8
80

25

120

25

240

10

60
-4.8

10

120

- 55°C to 25°C

-1

g:~c

Output noise voltage

25°C

75

480

75

Dropout voltage

25°C

2

2.5

2

~r'1

Bias current

25°C

4.8

7
0.8

4.8

;~

~Z

~~4r

10 = 200 mA
10

~
~

0>
~

10Hz to 100 kHz

Bias current change

In
N

f

Short-circuit
output current
Peak output current

=

VI - 15 V to 30 V
VI

=

-55°C to 150°C
OOC to 125°C

14.5Vto30V

-

-

-

-

mA

mA

0.5

25°C
25°C

V
6

0.5

OOC to 125°C

VI = 35 V

~V

0.8

-55°C to 150°C

5 mA to 350 mA

mV

mV/oC

-3.6

25°C to 150°C
OOC to 125°C

10 = 5mA

55

-

0.5

240

600

0.7

1.4

240
_ _ 0.7 _



~

Dropout voltage

FI'!'l

~Z

uA78M15M

TEST CONDITIONSt

10

23 V,IO

0.5

240

600

240

rnA

0.7

1.4

0.7

A

tPulse testing techniques are used to maintain the junction temperature as close to the ambient temperature as possible. Thermal effects must be taken into account separately.
:t:This specification applies only for de power dissipation permitted by absolute maximum ratings.

"'CI

o

en

::::::j

<:
m

!!!:

C)-

mU'l

=!!!:
mC)=

c>
.........
>=
.... !!!:

'"~
..,.
W

0=
enn
U'I

Data Sheets _ _

uA78M20C
POSITIVE·VOLTAGE REGULATOR
uA78M20C electrical characteristics at specified virtual junction temperature, VI = 29 V, 10
(unless otherwise noted)
PARAMETER

Output voltage ~

Ec

TEST CONDITIONSt

25°C
10 = 5mAt0350mA

Input regulation

10 = 200 mA

Ripple rejection

VI = 24 V to 34 V,
1=120Hz

Output regulation
Temperature coefficient

01 output voltage

VI = 23 V to 35 V

O°C to 125°C

VI = 23 V to 35 V

MIN

TYP

MAX

UNIT

19.2

20

20.8
21

V

10
5

100
50

mV

19

25°C

VI = 24 V to 35 V
10 = 100 rnA

OOC to 125°C

53

10 - 300 rnA

25°C

53

10 = 5mAt0500mA

25°C

10 = 5mAt0200mA

OOC to 125°C

10 = 5 rnA

400

10

200

Dropout voltage

25°C

2

Q)

Bias current

25°C

4.9

en

Bias current change

r+

=r

CD
CD

r+

en

Short~circuit

output current

10 = 200 mA,

VI = 23 V to 35 V

10 = 5 mA to 350 mA
VI = 35 V

Peak output current

~V

V

6
0.8

OOC to 125°C

mV
mV/oC

-1.1
110

Q)

1 = 10 Hz to 100 kHz

dB

70
30

25°C

Output noise voltage

= 350 rnA

0.5

mA
mA

25°C

240

rnA

25°C

0.7

A

tPulse testing techniques are used to maintain the junction temperature as close to the ambient temperature as possible. Thermal effects

must be taken into account separately.
:t:This specification applies only for de power dissipation permitted by absolute maximum ratings.

2-244

TEXAS .."

INSTRUMENTS
POST OFFICE BOX 655012 • DALLAS. TeXAS 75265

uA78M24C
POSITIVE·VOLTAGE REGULATOR
uA78M24C electrical characteristics at specified virtual junction temperature, VI = 33 V, 10 '" 350 mA
(unless otherwise noted)
PARAMETER

Output voltage

*

Input regulation

Ripple rejection

Output regulation
Temperature coefficient
of output voltage
Output noise voltage

TEST CONDITIONSt

25°C
10 = 5 rnA to 350 rnA

VI = 27 V to 38 V

OOCto 125°C

10 = 200 rnA

VI = 27 V to 38 V
VI = 28 V to 38 V

25°C

VI = 28 V to 38 V,
f=120Hz
10 -

Short-circuit

UNIT

25
25.2

V

10

100
50

rnV

5
50

10 = 300 rnA

25°C

50

5 rnA to 500 rnA

25°C
O°Cto 125°C

10 = 5 rnA

f = 10 Hz to 100 kHz

25°C

Bias current

output current

MAX

24

10 = 100 rnA

10 = 5 rnA to 200 rnA

10 = 200 rnA,

TYP

23
22.8

-55°C to 150°C
OOC to 125°C

Dropout voltage

Bias current change

MIN

VI = 27 V to 38 V

25°C
25°C
OOCto 125°C

dB

30

480

10

240

VI = 35 V

Peak output current

CI)

Q)
Q)

~V

170
2
5

rnV
rnV/oC

-1.2

OOC to 125°C

10 = 5 rnA to 350 rnA

PI
...

70

.c
en

V

6

rnA

0.8
0.5

rnA

...

C

25°C

240

rnA

25°C

0.7

A

CO
CO

tPulse testing techniques are used to maintain the junction temperature as close to the ambient temperature as possible. Thermal effects
must be taken into account separately.
tThis specification applies only for de power dissipation permitted by absolute maximum ratings.

TEXAS •

INSTRUMENTS
POST OFFICE BOX 655012 • DALLAS, TEXAS 75265

2-245

•

c

...
Q)

Q)

en
::r
CD
CD

...
UI

2-246

SERIES uA7900
NEGATIVE·VOLTAGE REGULATORS
02215. JUNE 1976-REVISEO AUGUST 1983

•
•

•
•
•
•
•
•

3·Terminal Regulators

NOMINAL
OUTPUT

Output Current Up to 1.5 A

REGULATOR

VOLTAGE

No External Components

v

uA7905C

-5.2 V

uA7952C

-6 V

uA7906C

-8 V

uA7908C

-12 V

uA7912C

-15 V

uA7915C

-5

Internal Thermal Overload Protection
High Power Dissipation Capability
Internal Short·Circuit Current limiting
Output Transistor Safe·Area Compensation
Essentially Equivalent to National LM320
Series

-18 V

uA7918C

-24 V

uA7924C

II
...

KC PACKAGE

I/)

description

(TOPVIEWI

This series of fixed-negative-voltage monolithic
integrated-circuit voltage regulators is designed
to complement Series uA7800 in a wide range
of applications. These applications include oncard regulation for elimination of noise and
distribution problems associated with singlepoint regulation. Each of these regulators can
deliver up to 1.5 amperes of output current. The
internal current limiting and thermal shutdown
features of these regulators make them
essentially immune to overload. In addition to
use as fixed-voltage regulators, these devices
can be used with external components to obtain
adjustable output voltages and currents and also
as the power pass element in precision
regulators.

Q)
Q)

~&~VrUT

.c

en

tl--.JC_l
__
....Fr======= COMMON

...
CO
CO

THE INPUT TERMINAL IS IN
ELECTRICAL CONTACT WITH
THE MOUNTING BASE

C

TO-220AB

schematic
12 Vta

lav

- - - + - + - - - - - + - - - o - - -....-COMMON.

OUTPUT
6.2V

INPUT __-~~-~

All component values are nominal.
Copyright @ 1983, Texas Instruments Incorporated

PRODUCTION DATA do.umonls .ontain information

currant as of publication data. Products conform to

specifications par the terms of Texas Instruments

=~~:~~;a{;:1~7i ~~~i~~ti:r :I~O::::::~::S not

TEXAS . "

INSTRUMENlS
POST OFFICE BOX 655012 • DALLAS. TEXAS 75265

2-247

SERIES uA7900
NEGATIVE·VOLTAGE REGULATORS
absolute maximum ratings over operating temperature range (unless otherwise noted)
uA7905C
THRU

I
I

Input voltage

uA7924C
All others

-35

Continuous total dissipation at 25 DC free-air temperature (see Note 1)

V

2
15

Continuous total dissipation at (or below) 25°C case temperature (see Note 1)
Operating free-air, case, or virtual junction temperature range

IE

UNIT

uA7924C
-40

Storage temperature range
Lead temperature 3.2 mm (1/8 inch) from case for 10 seconds

W
W

o to 150
-65 to 150

°C

260

°C

°C

NOTE 1: For operation above 25 DC free-air or CBse temperature. refer to Figures 1 and 2. To avoid exceeding the design maximum virtual
junction temperature, these ratings should not be exceeded. Due to variations in individual device electrical characteristics and
thermal resistance, the built-in thermal overload protection may be activated at power levels slightly above or below the rated
dissipation.

CASE TEMPERATURE
DISSIPATION DERATING CURVE

FREE·AIR TEMPERATURE
DISSIPATION DERATING CURVE
2000

:i:

E

"-

1800

I 1600

c
0

';co.

.,

1400

·iii

is 1200

.,
::I
0
::I
C

.~

1000
800

0

u
E
::I
E

.".
:E

600
400
200

16

"-f'"-~
"-~
"-

Derating factor - 16 mW/DC
R9JA ~ 62.5 DC/W

o

25

I

I

I

50

75

100

:i:
I

\

14

\

c

.j

12

1\
\

co.
iii
.!!! 10
0

.,
::I
0
::I
C

8

0

6

E
::I
E

4

~

u

'""-

125

1 50

T A - Free-Air Temperature- °c

.".
:E

\
,\
,\

Derating factor - 0.25 W/DC
above 900C
2 tRUC ~ 4 DC/W
I
I
I
o
125
25
50
75
100
Tc-Case Temperature- °C

\
150

FIGURE 2

FIGURE 1

recommended operating conditions

Input voltage, VI

uA7905C

MIN
-7

MAX
-25

uA7952C

-7.2

-25

uA7906C

-25

uA7908C

-8
-10.5

uA7912C

-14.5

-30

uA7915C
uA7918C

-17.5

-30

-21
-27

-33
1.5

A

0

125

°C

uA7924C
Output current, 10
Operating virtual junction temperature, T J

2·248

TEXAS . "

INSTRUMENTS
POST OFFICE BOX 655012 • DALLAS. TEXAS 75265

-25

UNIT

V

-38

uA7905C. uA7952C
NEGATIVE·VOLTAGE REGULATORS
uA7905C electrical characteristics at specified virtual junction temperature. VI - - 10 V. 10 - 500 mA
(unless otherwise noted)
TEST CONDITIONS t

PARAMETER

25°C
Output voltage*

Input regulation
Ripple rejection

Output regulation

10= 5 rnA to 1 A,
P:S; 15 W

VI = -7 Vto -20V,

25°C

- B V to -12 V

VI = -BVto -lBV, f = 120 Hz

uA7905C
TYP MAX
-5

OOC to 126°C -4.76

VI = - 7 V to - 25 V
VI -

MIN
-4.8

OOCto 125°C

10 = 5 rnA to 1.5 A

54

25°C

10 = 250 rnA to 750 rnA

UNIT

-5.2
-5.25

12.5

50

4

15

60

V

rnV

100

5

50

rnV

Temperature coefficient
of output voltage
Output noise voltage

f = 10 Hz to 100 kHz

25°C

125

~V

Dropout voltage

10 = 1 A

25°C

1.1

V

25°C

1.5

2

rnA

0.15

0.5
0.5

rnA

OOCto 125°C

10 = 5 rnA

Bias current

Bias current change

VI - -7 Vto -25 V
10 = 5 rnA to 1 A

Peak output current

0.08
2.1

25°C

...en

rnVloC

-0.4

OOC to 125°C

•

dB

15

Q)
Q)

.s::.
en

...
CO
CO

A

C

uA7952C electrical characteristics at specified virtual junction temperature. VI - - 10 V. 10 - 500 mA
(unless otherwise noted)
TEST CONDITIONS t

PARAMETER

MIN
25°C

Output voltage*

VI = -7.2Vto -20V,

10 = 5 rnA to 1 A,
P:s; 15 W

Input regulation

VI = -7.2 V to -25 V
VI - -B.2Vto -12V

Ripple rejection

VI = - B.2 V to -18 V, f = 120 Hz

Output regulation
Temperature coefficient

of output voltage
Output noise voltage
Dropout voltage

25°C
OOC to 125°C

10 = 5 rnA to 1.5 A

25°C

10 = 250 rnA to 750 rnA

OOCto 125°C

10 = 5 rnA

-5.2

OOC to 125°C -4.95

54

12.5

100

4

50

60
15

100

5

50

25°C

125

25°C
25°C

1.1
1.5

VI = -7.2Vto -25V

OOC to 125°C

10 - 5 rnA to 1 A

Peak output current

25°C

0.15
O.OB
2.1

V

rnV
dB

rnV
rnVloC

-0.4

10 = 1 A

UNIT

-5.4
-5.45

f = 10 Hz to 100 kHz

Bias current

Bias current change

-5

uA7952C
TYP MAX

~V

2
1.3
0.5

V
rnA
rnA
A

tPulse testing techniques are used to maintain the junction temperature as close to the ambient temperature as possible. Thermal effects
must be taken into account separately.
:t:This specification applies only for de power dissipation permitted by absolute maximum ratings.

TEXAS . "

INSTRUMENTS
POST OFFICE BOX 655012 • DALLAS. TEXAS 75265

2-249

uA7906C, uA790BC
NEGATIVE·VOLTAGE REGULATORS
uA7906C electrical characteristics at specified virtual junction temperature. VI
(unless otherwise noted)
PARAMETER

uA7906C

TEST CONDITIONSt

MIN
25°C

Output voltage ~

10

5 mA to 1 A,

~

VI -

-8Vto -21 V,

P:s 15 W
Input regulation

•

Ripple rejection
Output regulation

Temperature coefficient
of output voltage
Output noise voltage
Dropout voltage

VI

~

-8 V to -25 V

VI

~

- 9 V to -13 V

VI~

OOC to 125°C

120 Hz

O°C to 125°C

5 mA to 1.5 A

~

10
f

~

5mA

10 Hz to 100 kHz

Bias current
Bias current change

-6 -6.25
-6.3

54

~

-8 V to -25 V

10

~

5 mA to 1 A

60

60
120

5

60

150
1.1

25°C

500 rnA

UNIT

V

mV
dB

15

25°C

OOCt0125°C

Peak output current

120

4

25°C
25°C

VI

12.5

mV

mV/oC

-0.4

0°Ct0125°C

10 ~ 1 A

MAX

-5.7

25°C

10 ~ 250 mA to 750 mA

TYP

-5.75

25°C

-9Vto-19V,f~

~

10

= - 11 V. 10 ...

J.lV
V

1.5

2

0.15

1.3

0.08

0.5

2.1

mA
mA
A

uA 7908C electrical characteristics at specified virtual junction temperature. VI = - 14 V. 10 ... 500 rnA
(unless otherwise noted)

Output voltage ~

10

~

VI

5 mA to 1 A,

~

-10.5 V to -23 V,

P:s 15 W
Input regulation
Ripple rejection
Output regulation
Temperature coefficient
of output voltage

uA7908C

TEST CONDITIONSt

PARAMETER

MIN

TYP

MAX

25°C

-7.7

-8

-8.3

O°Cto 125°C

-7.6

VI ~ -10.5Vto -25V
~

VI

25°C

-11 Vto -17 V

VI -

-11.5 V to -21.5 V. f - 120 Hz

OOCto 125°C

10 ~ 5 mA to 1.5 A

25°C

10 ~ 250 mA to 750 mA
10
~

~

5 mA

Output noise voltage

f

Dropout voltage

10 ~ 1 A

0°Ct0125°C

10 Hz to 100 kHz

Bias current
Bias current change

10

~

5 mA to 1 A

160

4

80

15

160

5

80

1.1

25°C

mV

!'V
V

1.5

2

0.15

1

0.08

0.5

2.1

mV

mV/oC

-0.6

25°C

V

dB

60

200

OOCto 125°C

Peak output current

12.5

25°C
25°C

VI ~ - 10.5 V to - 25 V

54

-8.4

UNIT

mA
mA
A

tPulse testing techniques are used to maintain the junction temperature as close to the ambient temperature as possible. Thermal effects
must be taken into account separately.
*This specification applies only for dc power dissipation permitted by absolute .maximum ratings.

2-250

TEXAS •

INSTRUMENlS
POST OFFICE BOX 655012 • DALLAS, TEXAS 75265

uA7912C, uA7915C
NEGATIVE·VOLTAGE REGULATORS
uA7912C electrical characteristics at specified virtual junction temperature. VI - - 19 V. 10 - 500 mA
(unless otherwise noted)
PARAMETER

uA7912C

TEST CONDITIONSt

MIN

Output voltage t

Input regulation

VI = -14.5 V to -27 V,

10 = 5 rnA to 1 A,
p", 15W
VI -

-14.5Vto -30V

VI -

- 16 V to - 22 V

VI = -15 V to -25 V, f = 120 Hz

Output regulation

10 = 5 rnA to 1.5 A
10 = 250 rnA to 750 rnA

Temperature coefficient

of output voltage

OOeto 125°C -11.4

-12.6

ooe to 125°e

54

25°C

10 = 5 rnA

MAX

-12 -12.5

25°C

Ripple rejection

TYP

-11.5

25°C

5

SO

3

30

15

200

5

75

-0.8

V

rnV
dB

60

OOeto 125°C

UNIT

f = 10Hzto 100kHz

25°C

300

~V

Dropout voltage

10 = 1 A

25°C

1.1

V

25°C

Bias current change

VI -

-14.5Vto -30V

ooe to 125°C

10 = 5 rnA to 1 A

25°C

Peak output current

uA7915C electrical characteristics at specified virtual junction temperature. VI (unless otherwise noted)

Input regulation
Ripple rejection

Output regulation
Temperature coefficient

of output voltage

10 = 5 rnA to 1 A,
p", 15W

VI = -17.5Vto -30 V,

rnA

TYP

MAX

ooe to 125°e -14.25

-15.75

ooe to 125°C
25°C

10 = 250 rnA to 750 rnA

54

5

100

3

50

60
15
5

375

25°C
25°e

1.1
2

3

0.04

0.5

0.06

0.5

OOeto125°e
25°C

Peak output current

C

rnV

~V

25°C

10 = 1 A
-17.5 V to -30 V

CO
CO

rnV

rnV/oe

f = 10Hzto 100kHz

VI -

-

V

-1

Dropout voltage

10 = 5 rnA to 1 A

tJ)

dB

200
75

Output noise voltage

Bias current change

J:

UNIT

OOeto 125°e

Bias current

Q)
Q)

A

-15 -15.6

25°C

10 = 5 rnA

rnA

-14.4

VI - -17.5Vto-30V
VI = -20Vto -26 V
VI = -18.5Vto -2S.5V,f = 120 Hz
10 = 5 rnA to 1.5 A

3
0.5
0.5

en

-23 V.IO ,. 500 mA

MIN

25°e
Output voltage t

2
0.04
0.06
2.1

uA7915C

TEST CONDITIONSt

PARAMETER

-

rnV/oe

Output noise voltage
Bias current

PI

rnV

2.1

V
rnA
rnA
A

tPulse testing techniques are used to maintain the junction temperature as close to the ambient temperature as possible. Thermal effects
must be taken into account separately.
*This specification applies only for de power dissipation permitted by absolute maximum ratings.

TEXAS ."

INSIRUMENTS
POST OFFICE BOX 655012 • DALLAS. TEXAS 75265

2-251

uA7918C. uA7924C
NEGATIVE·VOLTAGE REGULATORS
uA7918C electrical characteristics at specified virtual junction temperature. VI - - 27 V. 10 = 500 mA
(unless otherwise noted)
PARAMETER

MIN

uA7918C
TYP MAX

-17.3

-18 -18.7

OOC to 125°C -17.1

-18.9

TEST CONDITIONst
25°C

Output voltage*

Input regulation

E

C

...

25°C

-24 V to -30 V

VI = -22Vto -32 V, f = 120Hz

Output regulation

10 = 5 rnA to 1.5 A
10 = 250 rnA to 750 rnA

OOCto 125°C

CD
CD

180

60

rnV
dB

360
180

rnV

OOC to 125°C

-1

rnV/oC

f = 10 Hz to 100 kHz

25°C

Dropout voltage

10 = 1 A

25°C
25°C

450
1.1

/LV
V

Bias current change

...en

360

30
10

25°C

10 = 5 rnA

Bias current

:T

54

5
3

V

Output noise voltage

of output voltage

en

VI -

Ripple rejection

Temperature coefficient

I»
I»

VI = -21 Vto -33V,
10= 5 rnA to 1 A,
P:s 15 W
VI - -21 Vto -33V

UNIT

VI -

- 21 V to -33 V

OOC to 125°C

10 = 5 rnA to 1 A

Peak output current

2

3

rnA

0.04

1
0.5

rnA

0.06
2.1

25°C

A

uA7924C electrical characteristics at specified virtual junction temperature. VI - - 33 V. 10 = 500 mA
(unless otherwise noted)
MIN
-23

uA7924C
TYP MAX
-24
-25

OOC to 125°C -22.8

-25.2

TEST CONDITIONst

PARAMETER

25°C
Output voltage *

VI = -27Vto -38 V,

10 = 5 rnA to 1 A,
P:s 15W

Input regulation

VI = -27 V to -38 V
VI - -30Vto -36V

Ripple rejection

VI = -28 V to -38 V, f = 120 Hz

Output regulation

Temperature coefficient
of output voltage

5

480
240

25°C

85
25

480
240

OOCto 125°C

-1

rnV/oC
/LV
V

OOCto125°C

10 = 5 rnA to 1.5 A
10 = 250 rnA to 750 rnA

54

Output noise voltage

f = 10 Hz to 100 kHz

25°C

600

Dropout voltage
Bias current

10 = 1 A

25°C
25°C

1.1
2

Bias current change

VI = - 27 V to - 38 V

OOC to 125°C

10 - 5 rnA to 1 A

V

3
60

25°C

10 = 5 rnA

UNIT

25°C

Peak output current

dB

0.04

3
1

0.06

0.5

2.1

rnV

rnV

rnA
rnA
A

tPulse testing techniques are used to maintain the junction temperature as close to the ambient temperature as possible. Thermal effects

must be taken into account separately.
iThis specification applies only for de power dissipation permitted by absolute maximum ratings.

2-252

TEXAS .."

INSTRUMENTS
POST OFFICE BOX 655012 • DALLAS, TEXAS 75265

SERIES uA79MOO
NEGATIVE-VOLTAGE REGULATORS
02216, JUNE 1976-REVISEO APRIL 1988

•

•
•
•
•
•
•

3-Terminal Regulators
Output Current Up to 500 mA

NOMINAL
OUTPUT

-55'C TO 150'C
OPERATING

O'C TO 125'C
OPERATING

VOLTAGE

TEMPERATURE RANGE

TEMPERATURE RANGE

-5 V

uA79M05M

uA79M05C

-6 V

uA79M06M

uA79M06C

Internal Shon-Circult Current limiting

-8 V
-12 V

uA79M08M
uA79M12M

uA79M08C
uA79M12C

Output Transistor Safe-Area Compensation

-15 V

uA79M15M

uA79M15C

No External Components
High Power Dissipation CapabiHty

Direct Replacements for Fairchild "A79MOO
Series

description

-20 V
-24 V

uA79M20C

•

uA79M24C

PACKAGE

JG

KC

schematic

This series of fixed-negative-voltage monolithic
integrated-circuit voltage regulators is designed
to complement Series uA/8MOO in a wide range
of applications, These applications include oncard regulation for elimination of noise and
distribution problems associated with singlepoint regulation. Each of these regulators can
deliver up to 500 rnA of output current. The
internal current limiting and thermal shutdown
features of these regulators make them
essentially immune to overload. In addition to
use as fixed-voltage regulators, these devices
can be used with external components to obtain
adjustable output voltages and currents and also
as the power pass element in precision
regulators.

OUTPUT

"-L....L.T-

If)

NC - No internal connection

Protection circuitry includes built-in under-voltage lockout and programmable current limiting in addition to
soft-start capability. A shutdown function is also available that can initiate either a complete shutdown with
automatic restart, or latch the supply off.
Other features include fully-latched operation, double-pulse suppression, deadtime adjustment capability,
and a ± 1% trimmed bandgap reference.
In the off state, the UC1846 outputs are low and the UC1847 outputs are high.
The UC1 846 and UC1 847 are characterized for operation over the full military temperature range of -55cC to
125cC, the UC2846 and UC2847 are characterized for operation from -25 cC to 85 cC, and the UC3846 and
UC3847 are characterized for operation from QCC to 7QcC.

PRODUCTION DATA documents conlain informalion
current as of publication data. Praduets conform to

spacifications par the terms af Taxas Instruments

::~~:~~i~.i~r:1~7i ~:~:~ti:.n lI~O::~::::~:~~ nat

TEXAS ~

INSTRUMENTS
POST OFFICE BOX 655012 • DALLAS, TeXAS 75265

Copyright @ 1988. Texas Instruments Incorporated

2-263

UC1846, UC1847, UC2846
UC2847, UC3846, UC3847

CURRENT-MODE PWM CONTROLLERS
functional block diagram

1-_ _ _ _ _ _ _ _ _ _ _..:1:;:.21 REFOUT

VIN 1151
SYNC.loI1~0:L1_

--------.,
_ _,,",ll=3I
I
VC

.....---.

OSC
. . .-+1:..;.1.:..:.11 AOUT

I
I
\

c
....
CI)
CI)

UC1S46
OUTPUT STAGE

CURRENT 131
SENSE I-I

\
\

UC1S47
IOUTPUTS INVERTEDI\

CURRENT 141
SENSE 1+1

en

:::r

~---.:I:.:.l4.::..1 BOUT

I
I

_

I
I
I

CD
CD

....

til

I

1121 GND

L____ ~ ______ J
l-<......~_ _ _-I-_ _ _ _ _ _ _ _ _ _ _ _1:..:.:.11 CURR LIM ADJI
SOFT START

1-_ _ _ _--<_-....!.!ll::!.61 SHUTDOWN
350 mV

2-264

TEXAS ."

INSTRUMENTS
POST OFFICE BOX 655012 • DALLAS, TEXAS 75265

6 kG

UC1846,UC1847,UC2846
UC2847,UC3846,UC3847

CURRENT-MODE PWM CONTROLLERS
absolute maximum ratings over operating free-air temperature range (unless otherwise noted)
Supply voltage, VIN (see Note 1) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40 V
Collector supply voltage, Vc . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40 V
Output current, source or sink, 10 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 500 mA
Analog input voltage (CURRENT SENSE (-), CURRENT SENSE (+), ERROR AMP (+),
ERROR AMP (-), or SHUTDOWN) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. -0.3 V to VIN
Reference output current . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . , -30 mA
SYNC output current . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -5 mA
Error amplifier output current . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. -5 mA
Soft-start sink current . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 50 mA
Oscillator charging current. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 5 mA
Continuous total dissipation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. See Dissipation Rating Table
Operating free-airtemperature range: UC1846, UC1847 ...................... -55°C to 125°C
UC2846, UC2847 ....................... -25°C to 85°C
UC3846, UC3847 ......................... O°C to 70°C
Storage temperature range .... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. -65°C to 150°C
Case temperature for 10 seconds: FN package. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 260°C
Lead temperature 1,6 mm (1/16 inch) from case for 60 seconds: J package ............... 300°C
Lead temperature 1,6 mm (1/16 inch) from case for 10 seconds: N package ............... 260°C

II
~

CI)

..!
en

...co
CO

C

NOTE 1: All voltage values are with respect to network ground terminal.
DISSIPATION RATING TABLE
PACKAGE

TA s 2SoC
POWER RATING

FN

1400mW

J

1375 mW

N

1150mW

DERATING FACTOR

= 2S'C
11.2 mwrc
11.0 mwrc
9.2mwrc

ABOVE TA

TA

= 70'C

TA

= 85'C

TA

= 12S'C

POWER RATING

POWER RATING

POWER RATING

896mW

728mW

880mW

715mW

280mW
275mW

736mW

598mW

TEXAS ",

INSTRUMENTS
POST OFFICE BOX 655012 • DALLAS, TEXAS 75265

2-265

UC1846, UC1847, UC2846
UC2847, UC3846, UC3847

CURRENT-MODE PWM CONTROLLERS
recommended operating conditions
UCl846, UCl847 UC2846, UC2847 UC3846, UC3847
MIN

8
-55

Supply voltage operating range, VIN
Operating free-air temperature, TA

c
II)
....
II)

....

MIN

MAX

3.9

V

2.5

40
125

8
-25

40

8
0

85

UNIT

2.5

V

40
70

V
°c

electrical characteristics over operating free-air temperature range, VIN = 15 V, RT = 10 kO,
CT = 4.7 nF (unless otherwise noted)
reference section
UC1846, UC1847
PARAMETER
Vo

t/)

:::T
CD
CD

MAX

3.9
2.5

Low-level input voltage, VIL (OSCillator Section)

•

MIN

MAX

3.9

High-level input voltage, VIH (Oscillator Section)

"VO

(II

TEST CONDITIONS
10~

Output voltage

~

TA - 25°C
8 V to 40 V

VIN(pin 15)

Load regulation

IIL-l rnA to lOrnA

MIN

TYP

MAX

5.05

5.1

5.1

5

20

3

15

Temperature coefficient of output
voltage
Total output variation

Short-circuit output current
(REFOUn

MAX

5

5.1

5.2

V

5

20

mV

3

15

VREF ~ 0

4.95

100
5
-10

-45

UNIT

TYP

0.4
5.2

5
1 kHz to 10 kHz,
TA ~ 25°C
t ~ 1000 hours, TA ~ 25°C

Output voltage long-term drift

UC3846, UC3847
MIN

0.4

f~

Output noise voltage

lOS

1 rnA,

Line regulation

UC2846, UC2847

-10

mV
mVrC

5.25

V

100

p.V

5

mV

-45

rnA

oscillator section
UC1846, UC1847
TEST CONDITIONS

PARAMETER
TA

Frequency change with
voltage

VIN(pin 15) ~ 8 V to 40 V

VT

Frequency change with
temperature
Threshold voltage (SYNC)

VOH

High-level output voltage
(SYNC)

VOL

Low-level output voltage
(SYNC)

II

Input current (SYNC)

2-266

~

Initial accuracy

25°C

UC2846, UC2847
MIN

TYP

39

UC3846, UC3847

MAX

MIN

43

47

39

-1%

±2%

-1%
2.5

TYP
43

47

-1%

±2%

3.9

2.5

3.9

3.9

TEXAS

~

INSTRUMENlS
POST OFFICE BOX 655012 • DALLAS, TEXAS 75265

1.5

V
V

2.5
1.3

CTatOV

kHz

-1%

3.9

Sync voltage - 5.25 V,

UNIT

MAX

1.3

2.5

V

1.5

rnA

UC1846, UC1847, UC2846
UC2847, UC3846, UC3847

CURRENT-MODE PWM CONTROLLERS
electrical characteristics over operating free-air temperature range, VIN = 15 V, RT = 10 kil,
CT 4.7 nF (unless otherwise noted) (continued)

=

error amplifier section
UC1846, UC1847
PARAMETER

TEST CONDITIONS

UC3846, UC3847

UC2846, UC2847
MIN

TYP

MAX

MIN

TYP

UNIT

MAX

VIO

Input offset voltage

0.5

5

0.5

5

110

Input offset current

40

40

250

nA

liB

Input bias current

250
-1

-0.6

-1

!lA

VOH

High-level output voltage

Rl(COMP) - 15 k!l

4.3

4.6

-0.4

-0.5

-0.6

10H

High-level output current

VID = 15 mVto 5 V,
COMPat2.5V

VOL

low-level output voltage

RL(COMP) = 15 k!l

10l

low-level output current

VID = -15 mV to -5 V,
COMPatl.2V

AVD

Common-mode input voltage range

Open-loop voltage amplification

CMRR Common-mode rejection ratio
kSVR

Supply-voltage rejection ratio

VIN = 8 V to 40 V

-0.4

-0.5

V
mA

0.7

6

2

1

6

V

PI

mA

a

a
VICR

4.6

1

0.7
2

4.3

mV

to

to

VIN-2

VIN-2

V

/lVO = 1.2Vt03V,
VIC = 2V

80

105

80

105

dB

VIC = Oto 38V,
VIN = 40V

75

100

75

100

dB

VIN = 8 V to 40 V

80

105

80

105

dB

current-sense amplifier section
UC1846, UC1847
PARAMETER

TEST CONDITIONS

MIN
VIO

Input offset voltage

110

Input offset current

liB

Input bias current

AV

Voltage amplification

CURR LIM ADJ/SOFT START
at 0.5 V, COMP open, See
Note 3
CURRENT SENSE (-) at

UC3846, UC3847

UC2846, UC2847
TYP

MAX

MIN

UNIT

TYP

MAX

5

25

5

25

0.08

1

0.08

1

I1A

-2.5

-10

-2.5

-10

!lA

2.75

3

2.75

3

a V,

CURR LIM ADJ/SOFT START

2.5

2.5

mV

V

open, See Notes 2 and 3
VICR

a

a

Common-mode input voltage
range

to

to

VIN-3

VIN-3

V

CURR LIM ADJ/SOFT START
Maximum usable differential
input signal
CMRR Common-mode rejection ratio
kSVR
td

open, Rl(COMP) = 15 kfl,
See Note 2

1.1

1.3

1.1

1.2

V
dB

VIC-1Vto12V

60

83

60

83

Supply-voltage rejection ratio

VIN - 8 V to 40 V

60

60

84

Input-to-output delay time

TA - 25"C

84
200

600

200

NOTES: 2. This parameter is measured at the trip point of the latch with ERROR AMP (+) at VREF, ERROR AMP (-) at
3. Amplifier gain is defined as:

600

dB
ns

a v.

AV = /lVPIN7
/lVpIN4
Where:
/lVpIN4 = OVto 1.0 V

TEXAS ",

INSTRUMENTS
POST OFFICE BOX 655012 • DALLAS. TEXAS 75265

2-267

UC1846, UC1847, UC2846
UC2847, UC3846, UC3847

CURRENT-MODE PWM CONTROLLERS
electrical characteristics over operating free-air temperature range, VIN
CT 4.7 nF (unless otherwise noted) (continued)

= 10 k!1,

15 V, RT

=

current limit adjustment section
UC1846, UC1847
PARAMETER

TEST CONDITIONS

UC3846, UC3847

UC2846, UC2847

UNIT

MIN

TYP

MAX

MIN

TYP

MAX

0.45

0.5

0.55

0.45

0.5

0.55

V

-10

-30

-10

-30

vA

CURRENT SENSE (-) at 0 V,
VIO

E
C

...

Input offset voltage

CURRENT SENSE (+) at 0 V,
COMP open, See Note 3

liB

Input bias current

ERROR AMP (+) at VREF,
ERROR AMP (-) at 0 V

shutdown terminal section

I»
I»

UC1846, UC1847
PARAMETER

TEST CONDITIONS

(J)

:r
CD
CD

VT

Ul

VI

...

Differential-input threshold voltage
Input voltage range
Minimum latching current
(CURR LIM ADJ/SOFT START)

See Note 4

Output delay

TA = 25'C

UC3846, UC3847

UC2846, UC2847

UNIT

MIN

TYP

MAX

MIN

TYP

MAX

250
0

350

400

250

350

400

mV

a

to

to

VIN

VIN

0.8

1.5

3

300

600

0.8

V

1.5

3

mA

300

600

ns

output section
UC1846, UC1847
PARAMETER

TEST CONDITIONS

MIN

TYP

V(BR)CE

Collector-emitter breakdown
voltage

ICEX

Collector-emitter off-state current

VCE = 40 V,

High-level output voltage

IOH - -20mA

13

13.5

(AOUT and BOUT)

IOH - -100mA

12

13.5

Low-level output voltage

IOL= 20mA
IOL = 100 mA

VOH
VOL
tr

(AOUT and BOUT)
Rise time (AOUT and BOUT)

tf

Fall time (AOUT and BOUT)

UC3846, UC3847

UC2846, UC2847
MAX

40

CL = 1 nF,

MIN

TYP

UNIT

MAX

40

See Note 5

V

200

TA = 25'C

200
13

13.5

12

13.5

vA
V

0.1

0.4

0.1

0.4

0.4
50

2.1
300

0.4

2.1

50

300

50
50

300
300

V
ns
ns

under-voltage lockout section
UC1846, UC1847
PARAMETER

TEST CONDITIONS

UC3846, UC3847

UC2846, UC2847
MIN

Startup threshold
Threshold hysteresis

TYP

MAX

7.7
0.75

8

MIN

UNIT

TYP

MAX

7.7
0.75

8

NOTES: 3. This parameter is measured at the trip point of the latch with ERROR AMP (+) at VREF and ERROR AMP (-) at 0 V.
4. This is the lowest current into Pin 1 that will latch the circuit in the shutdown state.
5. This applies for UC1846, UC2846, and UC3846 only (due to polarity of outputs).

2-268

TEXAS •

INSTRUMENTS
POST OFFICE BOX 655012 • DALLAS, TEXAS 75265

V
V

UC1846, UC1847, UC2846
UC2847, UC3846, UC3847

CURRENT-MODE PWM CONTROLLERS
electrical characteristics over operating free-air temperature range, VIN = 15 V, RT = 10 kil,
CT
4.7 nF (unless otherwise noted) (continued)
total device

=

UC1846, UC1847
TEST CONDITIONS

PARAMETER

UC2846, UC2847
MIN

TVP

MAX

17

21

Supply current

ERROR AMPLIFIER AMPLIFICATION AND PHASE
vs
FREQUENCY
~ 100
VIN-20V
I
c 90
TA - 25°C
·8 80
RL - 12 k!l
70

'"

i
«
.

E 60
50

~'"
>

"'"

"'" "'-

30

iij

c

20

Ui'" 10
;,
I!' 0

....I

100

1 k

10 k

100 k

21

rnA

..s::::

CI)

...
CIS
CIS

!

o

51

f

'\

0°
-90.

-I--..

«>

17

UNIT

CI)
CI)

.!!

"'" "" "'-

MAX

CI)

"'-

40

TVP

PI
...

TYPICAL CHARACTERISTICS

.

UC3846, UC3847
MIN

180·

1 M

!
i:

g

Frequency - Hz

FIGURE 1
ERROR AMPLIFIER LARGE-SIGNAL DC AMPLIFICATION
vs
LOAD RESISTANCE
~ 110
I
VIN - 20 V
6 105 TA - 25·C
1100

~

J~

90

~

85

~

80

j

75

~
I

~

/'

95

70

V

/
I
o

20
40
60
80
100
RL -Output Load Resistance-k!l

120

FIGURE 2

TEXAS ",
INSTRUMENTS
POST OFFICE BOX 655012 • DALLAS, TEXAS 75265

2-269

UC1846, UC1847, UC2846
UC2847, UC3846, UC3847

CURRENT-MODE PWM CONTROLLERS
TYPICAL APPLICATION DATA
VREF~12~)----~----------,

19)

18)

C

RT

m
m

r+

en

:::r
CD
CD

OSCILLATOR CIRCUIT

r+

o

SAWTOOTH
IPIN 8)

n n

SYNC
(PIN 101_ _ _--!

'-_ _ __

I

I
--+I

I

(

I + - OUTPUT DEADTIME (tdeadl

OSCILLATOR WAVEFORMS
NOTE: Oscillator frequency is approximated by the formula: fT

~ ~

RTCT

Output deadtime is determined by the size of the external capacitor, CT, according to the following formula:
tdead

=

145 CT(_ _
12__
12 3.6

)

RT Iklll
For large values of RT. tdead " 145 CT

FIGURE 3. OSCILLATOR CIRCUIT

2-270

TEXAS ",
INSTRUMENlS
POST OFFICE BOX 655012 • DALLAS. TEXAS 75265

UC1846, UC1847, UC2846
UC2847, UC3846, UC3847

CURRENT·MODE PWM CONTROLLERS
TYPICAL APPLICATION DATA

0.5 mA

~

CaMP

II
...
en

1< 0.5 mA

Q)
Q)

.c

NOTE: Error Amplifier can source up to 0.5 rnA.

FIGURE 4. ERROR AMPLIFIER OUTPUT CONFIGURATION
IS

en

...caca

Q
(41

RS
0.5 mA

+

Rl
111

CURRENT
R2

LIMIT

(71
CaMP

NOTE: Peak Current 1151 is determined by the formula: Is

=

R2 VREF _ 0.5 V
_Rl_+_R--::2-::-_ _

3RS
FIGURE 5. PULSE-BY-PULSE CURRENT LIMITING

TEXAS ",

INSTRUMENTS
POST OFFICE BOX 655012 • DALLAS, TEXAS 76265

2-271

UC1846, UC1847, UC2846
UC2847, UC3846, UC3847

CURRENT·MODE PWM CONTROLLERS
TYPICAL APPLICATION DATA

C

m
m

r+

en
:::r
CD
CD

n

r+

en

116

)1

I ..r-t +
IL... _ _

.,.. 350 mV

_

SOFT START AND SHUTDOWN/RESTART CIRCUIT

----~-----SHUTDOWN
(PIN 16)
ON----,11._ _ _ _ _ _ _..1 1._ _ _ _ _ _ __
OFF

n

_ .....n'-___
JUl'---_ __

PWM
VREF

<

V:~F >

0.8 mA

Rl
NOTE: If

VREF < 0.8 mAo the shutdown latch will commutate
R1

when ISS

= 0.8 mA

and a restart cycle will be initiated.

SHUTDOWN WITH AUTO-RESTART

NOTE: If

VREF

3 mA (LATCHED OFF)

> 3 rnA. the device will latch off until power

Rl
is cycled.
SHUTDOWN WITHOUT AUTO-RESTART ILATCHED)

FIGURE 6. SOFT START AND SHUTDOWN/RESTART FUNCTIONS

2-272

TEXAS . "

INSTRUMENTS
POST OFFICE BOX 655012 • DALLAS, TEXAS 75265

UC1846, UC1847, UC2846
UC2847, UC3846, UC3847
CURRENT·MODE PWM CONTROLLERS
TYPICAL APPLICATION DATA
(9)

(8)

RT
MASTER
CT

RT

VREF

~CT

+E/A SYNC COMP
(10)

(2)

-E/A

~

(7)

':'

OUTPUT
FILTERS

II
...
II)

CI)
CI)

(2)

VREF
(91

(81

(101

+E/A

.c:
tn

(71

SYNC COMP

...
CIS
CIS

-E/A

RT

Q

SLAVE
(ADDITIONAL UNITS)

~

CT

':'

NOTE: Slaving allows parallel operation of two or more units with equal current sharing.

FIGURE 7. PARALLEL OPERATION

TEXAS ~

INSTRUMENTS
POST OFFICE BOX 655012 • DAI-LAS, TEXAS 75265

2-273

c

...
II)

II)

en
~

...en
CD
CD

2-274

~_p_ro_d_u_c_t_p_r_e_v_ie_w_s______________~'_111

~1

•
...o

."
Co

...s::
(')

...

."
CD

<
::e
tn

CD'

3-2

LT1036M, LT1036C
LOGIC·CONTROLLEO POSITIVE REGULATORS
03219. JULY 1988-REVISED JANUARY 1989

KJ PACKAGE
(TOP VIEW)

•

Two Regulated Outputs
+12Vat3A
+5 V at 75 mA

•

2% Output Voltage Tolerance

•

SO·dB Ripple Rejection

•

0.7% Output Regulation

•

100% Thermal-Limit Burn-In

•

TTL and CMOS Compatible Logic Control

4 LEAD TO-3
KV PACKAGE
(TOP VIEW)

description
The LT1 036 contains two positive regulators in
the same package. The 12-V main regulator
supplies current up to 3 A and the auxiliary 5-V
regulator supplies up to 75 mAo The 12-V main
regulator has an additional feature that allows
a logiC signal to control its operation. When the
enable input is taken to a low logic level, the
main regulator shuts down and its output voltage
goes to near 0 V. The auxiliary regulator at this
time is unaffected and continues to provide a 5-V
output.
The 12-V main output has current and power
limiting combined with thermal shutdown to
make it very reliable. The 5-V auxiliary output is
not affected by the thermal shutdown circuits
or the state of the 12-V main output. This allows
it to be used as a back-up in case of overloads
on the main supply. The logic enable input of the
LT1 036 has a 1 .6-V threshold and can be driven
by most logic families including TTL and CMOS.

GND

4-AUX

(TAB)

I~II

jl:.D

~o

1 . . . - .- "
•• -

•

t

1-0UT 2-EN
5 LEAD TO-220

II
U)

AVAILABLE OPTIONS
PACKAGE
4 LEAD
5 LEAD

TJ

TO-3

TO-220

KJ

KV
LTlO36CKV

OOC to 125°C

LT1036CKJ

-55°C to 150°C

LTlO36MKJ

:=CD

..

.~

...

D.

Co)

::::s

..

"C

o

D.

Typical applications include power supply
sequencing, remote on/off power control,
selective system power during emergency
power operation, and power supply with backup.

PRODUCT PREVIEW documents conlain in'ormation

an products in the mrmative or design

~hase

of

development. Characteristic data anil othar

specifications ar. design goals. Texas Instruments
reserves the right to change Of discontinue these
products without notice.

TEXAS

~

INSTRUMENTS
POST OFFICE BOX 655012 • DALLAS, TEXAS 75265

Copyright @ 1989, Texas Instruments Incorporated

3-3

LT1036M, LT1036C
LOGIC·CONTROLLED POSITIVE REGULATORS
schematic diagram
:~'-,------t--t--"t--------------------1r----"""'----------,

D2

'v

'0'

141

0.03

AUX
OUT

111
OUT

4.8 k

•..

2.

-a

o

Q.

C

(")

r+

-a
CD

<
a)"
~

til

L----~--~-~~--*--~-~~~--~~~-~_+---~~-----~-~D
EN(21

A" resistor values are nominal and in ohms.

absolute maximum ratings over operating virtual·junction temperature range (unless otherwise noted)
Input voltage, VI ................ '.' . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 30 V
Enable voltage, VEN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 30 V
Continuous power dissipation, PO. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 24 W
Power dissipation under fault conditions. . . . . . . . . . . . . . . . . . . . . . . . . . . . .. Internally self-limited
Operating virtual junction temperature range: LT1 036M . . . . . . . . . . . . . . . . . . .. - 55°C to 150°C
LT1036C ...................... O°C to 125°C
Storage temperature range ......................................... - 65°C to 150°C
Lead temperature 1,6 mm (1/16 inchl from case for 10 seconds: KJ package ............ 300°C
Lead temperature 1,6 mm (1/16 inchl from case for 10 seconds: KV package. . . . . . . . . . .. 260°C

recommended operating conditions
MIN

Output current, 10

I

Operating junction temperature, T J

3-4

I

TEXAS . "

INSTRUMENlS
POST OFFICE BOX 655012 • DALLAS, TEXAS 75265

LT1036M
LT1036C

-55
0

MAX
3
150
125

UNIT
A
·C
·C

LT1054
SWITCHED·CAPACITOR VOLTAGE CONVERTER
WITH REGULATOR
03202. JANUARY 1989

•

Output Current . . . 100 mA

•

Low Loss ... 1.1 Vat 100 mA

•

Operating Range ... 3.5 V to 15 V

•

Reference and Error Amplifier for Regulation

JG AND P PACKAGE
ITOPVIEW)

•

External Shutdown

•

External Oscillator Synchronization

•

Devices Can Be Paralleled

•

Pin Compatible with the LTC1044/7660

FB/SDD8 VCC
CAP+ 2
7 OSC
GND 3
6 VREF
CAP- 4
5 VOUT
L PACKAGE
ITOPVIEW)

VCC

AVAILABLE OPTIONS
PACKAGE
TA

CERAMIC DIP
IJG)

METAL CAN
IL)

PLASTIC DIP
IP)

LTlO54CJG

LTlO54CL

LT1054CP

LT1054MJG

LTlO54ML

N/A

CAP-

OOC

to

•

70°C
-55°C

to
125°C

description
The LT1 054 is a monolithic, bipolar, switched capacitor voltage converter and regulator. It provides higher
output current and significantly lower voltage losses than previously available converters. An adaptive
switch drive scheme optimizes efficiency over a wide range of output currents. Total voltage drop at 100 mA
output current is typically 1.1 V. This holds true over the full supply voltage range of 3.5 V to 15 V.
Quiescent current is typically 2.5 mAo
The LT1 054 also provides regulation, a feature not previously available in switched capacitor voltage
converters. By adding an external resistive divider, a regulated output can be obtained. This output is
regulated against changes in both input voltage and output current. The LT1 054 can also be shut down
by grounding the feedback pin. Supply current in shut down is less than 100 /LA.

...
U
j

"C

e

D..

The internal oscillator of the LT1 054 runs at a nominal frequency of 25 kHz. The oscillator pin can be
used to adjust the switching frequency, or to externally synchronize the LT1 054.
The LT1 054 is pin compatible with previous converters such as the LTC1044/7660.

Copyright @ 1989, Texas Instruments Incorporated

PRODUCT PREVIEW documonts .ontoi. information

on products in the formative Dr design ~hl" of
development. Characteristic data Inll othar

~:::.at:=:.ri8gr:t d:i~.=::I~rT:i=~'::7=
products without nolice.

TEXAS . "

INSTRUMENTS
POST OFFICE BOX 655012 • DALLAS. TEXAS 75265

3·5

LT1054
SWITCHED-CAPACITOR VOLTAGE CONVERTER
WITH REGULATOR
functional block diagram
VREF

Vcc+

r -________________________--t(SI
2.5 V

R

+_-+;;'1

FS/SO.:..;(1"'1....

OSC~(7~1_+-_-+_-H~

..

"'tI

oQ.

* External capacitors

C

2.

..

"'tI
CD

<

i"

:etil

absolute maximum ratings over operating free-air temperature range (unless otherwise noted)
Supply voltage, Vee (see Note 1) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 16 V
Input voltage, FB/SD terminal. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 0 V to Vee +
Input voltage, OSC terminal .............................................. 0 V to Vref
Junction temperature (see Note 2): LT1 054e. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 125°e
LT1054M ................................... 150 0 e
Storage temperature range ......................................... - 55 °e to 150 0 e
Lead temperature, 1,6 mm (1/16 inch) from case for 10 seconds: JG or L package ....... 300 0 e
Lead temperature, 1,6 mm (1/16 inch) from case for 10 seconds: P package . . . . . . . . . . .. 260 0 e
NOTES: 1. The absolute maximum supply voltage rating of 16 V is for unregulated circuits. For regulation mode circuits with Va
this rating may be increased to 20 V.
2. The devices are functional up to the absolute maximum junction temperature.

3-6

TEXAS . "

INSTRUMENTS
POST OFFICE BOX 655012 • DALLAS, TEXAS 75265

s

15 V.

LT1054
SWITCHED·CAPACITOR VOLTAGE CONVERTER
WITH REGULATOR
recommended operating conditions
Vee

Supply voltage

TA

Operating free-air temperature

I LT1054e
I LTl054M

MIN
3.5

MAX

0
-55

70
125

15

UNIT
V
°e

electrical characteristics
PARAMETER

TEST CONDITIONS

Regulated output voltage. Va
Input regulation
Output regulation

Voltage loss. Vee (see Note 4)

Vce
Vce

=
=

7 V. TJ

=

TAt

25°C. See Note 3

7 V to 12 V. See Note 3

Vee - 7 V. RL - 100

n to

500

110
110

n.

See Note 3

=
=

Output resistance

10 mA
CI = Co = ~F tantalum
100 mA
dlO = 10 mA to 100 mAo See Note 5

Oscillator frequency

Vee

Reference voltage. Vref

Iref

=

10

=0

IVai

= 3.5 V to
60 ~A. TJ

25°C
Full range

SupplV current in shutdown

TYP
-5

V
mV

Full range

50

mV

Full range
Full range

0.35
1.1

0.55
1.6

Full range

10

15
35
2.65

Full range

15

25

=

25°e
Full range

2.35

2.5

25°C

I VI = 3.5 V
I VI = 15 V

Full range

Full range
Full range

VFB/SD - 0 V

UNIT

25

15 V
25°e

MAX
-5.2

5
10

Maximum switch current

Supply current. lee

MIN
-4.7

2.25

2.75
300
2.5

3.5

3
100

150

V

n
kHz
V
mA

4.5

mA
~V

tFull range is -55°e to 125°e for the LTl054M and ooC to 70 e for the LTl054e. For the LTl054e. the specifications apply up to
0

°e.

a junction temperature of 100
NOTES: 3. All regulation specifications are for a device connected as a positive to negative converter/regulator with R1 = 20 kO,

R2 = 102.5 kn. el = 10 ~F (tantalum). and eO = 100 ~F (tantalum).
4. For voltage-loss tests, the device is connected as a voltage inverter, with pins 1,6, and 7 unconnected. The voltage losses
may be higher in other configurations.
5. Output resistance is defined as the slope of the curve (dVO vs dlO) for output currents of 10 mA to 100 mAo This represents
the linear portion of the curve. The incremental slope of the curve will be higher at currents of less than 10 rnA due to the
characteristics of the switch transistors.

II
U)

~

CD

"$

...

CD

...

D..

U
:::::I

"C

o...

D..

TEXAS . "

INSTRUMENlS
POST OFFICE BOX 655012 • DALLAS, TEXAS 75265

3-7

..

"'tI

oQ.
s::

(')
....

..

"'tI

CD

<

CD'
~

til

3-8

LT1070, LT1070HV
5·A HIGH·EFFICIENCY SWITCHING REGULATOR
03222, OCTOBER 198B

•

Wide Supply Voltage Range:
LT1070HV ... 3 V to 60 V
LT1070 ... 3 V to 40 V

•

Low Quiescent Current ... 6 mA Typ

KJ PACKAGE
(TOP VIEW)

•

Internal 5·A Switch

•

Very Few External Parts Required

•

Self·Protected Against Overloads

•

Operates in Nearly All Switching Topologies

•

Low Shutdown·Mode Supply Current

•

Fully Floating Outputs in Flyback·Regulated
Mode

•

Available in Standard KV and KJ Packages

•

Can be Externally Synchronized
AVAILABLE OPTIONS
TJ

MAX INPUT
VOLTAGE

KJ
PACKAGE

CASE IS GND
KV PACKAGE
(TOP VIEW)

§I Iii

KV
PACKAGE

O·C

60V

LT1070HVCKJ LTl 070HVCKV

to
l00·C

40V

LT1070CKJ

-55·C

60V

LT1070HVMKJ

40 V

LT1070MKJ

~

0>
...
a..
Q)

to
150·C

•
en

LTl070CKV

Q)

...

description

(,)

The LT1 070 is a monolithic, high-power switching regulator. It can be operated in all standard switching
configurations including: buck, boost, flyback, forward, inverting, and Cukt. A high-current, high-efficiency
switch is included in the package along with all oscillator, control, and protection circuitry, Integration
of all functions allows the LT1 070 to be built in a standard 5-pin KV package and the 4-pin case-ground
KJ power package. This makes it extremely easy to use and provides bust-proof operation similar to that
obtained with 3-pin linear regulators.

::l

"C

e

a..

The LT1070 operates with supply voltages from 3 V to 40 V. The LT1070HV, a high-voltage version of
the LT1 070, operates with supply voltages from 3 V to 60 V. These devices draw only 6-mA quiescent
current, deliver load power up to 100 W with no external power devices, and by utilizing current-mode
switching techniques, they provide excellent ac and dc input and output regulation.
The LT1 070 is much easier to use than the low-power control chips that are presently available and has
many unique features that are not found on these chips. It uses an adaptive saturation-preventing switch
drive to allow very-wide-ranging load currents with no loss in efficiency. An externally activated shutdown
mode reduces total supply current to 50 p.A typical for standby operation. Totally isolated and regulated
outputs can be generated by using the optional "flyback regulation mode" built into the LT1 070, without
the need for optocouplers or extra transformer windings.

tBoost-buck-derived regulator circuit patented by Siobodan /;uk.

PRODUCT PREVIEW do.umonts contain information
on products in tho 'ormali.. or dOlig. ~h.so of
davelopmant. Characteristic data Inil othar

:=;:'at=:1rrg~ dt:i~~=::I~r TIi::~=::~C:'~
preducts withDUt notice.

Copyright @ 1989. Texas Instruments Incorporated

TEXAS ",
INSTRUMENTS
POST OFFICE BOX 655012 • DALLAS, TeXAS 75265

3-9

LT1070, LT1070HV
5-A HIGH-EFFICIENCY SWITCHING REGULATOR
functional block diagram
IN

FB+---~-l

~-----+----------------------~c

"'tJ

o
Q.
c

SHUTDOWN
CIRCUIT

n
r+

..."'tJ

(1)

0.02

[J

+

<

iii'

0.15 V

:e

(II

absolute maximum ratings over operating virtual junction temperature range (unless otherwise noted)
Input voltage, VI (see Note 1}: LT1 070 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 40 V
LT1070HV ....................................... 60 V
Switch output voltage: LT1070 ............. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 65 V
LT1070HV ............................................. 75 V
Feedback pin voltage, VFB (transient, 1 ms). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. ± 15 V
Operating virtual junction temperature range:
LT1070C, LT1070HVC (normal operation) ............................. oDe to 100 DC
LT1 070C, LT1 070HVC (short-circuit operation) ......................... 0 DC to 125 DC
LT1 070M, LT1 070HVM ........................................ - 55 DC to 150 DC
Storage temperature range ......................................... - 65 DC to 150 DC
Lead temperature, 1,6 mm (1/16 inch) from case for 10 seconds: ..................... 300 DC
NOTE 1: Minimum switch~on time for the LT1070 in current limit is =1 pS. This limits the maximum input voltage during short-circuit
conditions, in the buck and inverting modes only. to ~35 V. Normal (unshorted) conditions are not affected. If the LT1070 is
being operated in the buck or inverting mode at high input voltages and short-circuit conditions are expected. a resistor must
be placed in series with the inductor.

3-10

TEXAS . "

INSTRUMENlS
POST OFFICE BOX 655012 • DALLAS, TEXAS 75265

LT1D84M, LT1D84C
5-AMP, LOW-DROPOUT, ADJUSTABLE POSITIVE REGULATORS
D3118, JULY 1988-REVISED JANUARY 1989

•

Adjustable Output ... 1 V to 35 V

•

5-A Output Capability

KA PACKAGE
(TOP VIEW)

•

Dropout Voltage .. , 5 V Max

•

Input Regulation .•. 0.015% Typ

•

Output Regulation. , .0,01% Typ

•

100% Thermal Limit Burn-In

OUT~-IN
C'

(CASE)

o

0
('>

1-ADJ
TO-3

description
The LT1 084 is a 3-terminal adjustable positive
regulator that operates with higher efficiency
than currently available devices with output
loads up to 5 A. Internal circuitry is designed to
operate with a small input-to-output differential
voltage of 1 ,3 V (typical) and all dropout voltages
are specified as a function of output current,
Dropout voltage reaches a maximum of 1,5 V
at maximum output currents. On-chip circuitry
holds the reference voltage constant to within
1 %, Current limiting is used to minimize the
stress on both the regulator and power source
circuits under overload conditions,
The LT1 084 is pin compatible with older
3-terminal regulators. A 10-"F output capacitor
is required, as in most regulator designs. In
P-N-P regulators, up to 10% of the output
current is lost as bias (quiescent) current, but
LT1 084 bias current flows into the load, which
improves power efficiency.

KK PACKAGE
(TOP VIEW)

AVAILABLE OPTIONS
PACKAGE
METAL

TJ

TO-3
KA

OOCto 125°C

LT1084CKA

-55°C to 150°C

LT1084MKA

PLASTIC
KK
LT1084CKK

~

U

::::I

"o

~

Typical applications include high-efficiency linear
regulators, post regulators for switching power
supplies, constant-current regulators, and
battery chargers.

PRODUCT PREVIEW documants conlain information
on pradum in the '.rmativ8 or design ,.han of
development. Characteristic data Inil other
specifications are design goals. TBxas Instruments
r..,rvas the right to change or discontinua thBl.

products without notice.

II
0.

Copyright © 1989, Texas Instruments Incorporated

TEXAS . "

INSTRUMENTS
POST OFFICE BOX 655012 • DALLAS, TEXAS 75265

3-11

LT1084M, LT1084C
5-AMP, LOW~DROPOUT, ADJUSTABLE POSITIVE REGULATORS
functional block diagram

OUT
ICASE)

(1) ADJ

."

ac.

absolute maximum ratings over operating temperature range (unless otherwise noted)
Input-to-output differential voltage: LT1084M ..................................... 35 V
LT1084C ..................................... 30 V
Power dissipation .............................................. Internally self-limited
Operating virtual-junction temperature range: LTl 084M Control section. . . . . . .. - 55°C to 150°C
LTl084M Power transistor ....... -55°C to 200°C
LTl 084C Control section. . . . . . . . . .. OOC to 125°C
LTl 084C Power transistor. . . . . . . . .. OOC to 150°C
Storage temperature range ......................................... - 65°C to 150°C
Lead temperature 1,6 mm (1/16 inch) from case for 10 seconds: KA package. . . . . . . . . . .. 300°C
Lead temperature 1,6 mm (1/16 inch) from case for 10 seconds: KK package ............ 260°C

c

....
(')

."

;

<

(j)'

:e

(I)

recommended operating conditions
MIN

MAX

Output current. 10

Operating virtual-junction temperature, T J

3-12

LT1 084M Control section

0

5
125

LT1 084M Power transistor

0

150

LT1 084C Control section

0

125

LT1 084C Power transistor

0

150

TEXAS ~

INSTRUMENTS
POST OFFICE BOX 655012 • DALLAS. TeXAS 75265

UNIT
A

·C

TL499AC
WIDE-RANGE POWER SUPPLY CONTROLLER
02762, JANUARY 1984-REVISED FEBRUARY 1989

•

o OR P PACKAGE

Internal Series-Pass and Step-Up Switching
Regulator

•

Output Adjustable from 2.9 V to 30 V

•

1-V to 10-V Input for Switching Regulator

•

4.5-V to 32-V Input for Series Regulator

•

Externally Controlled Switching Current

•

No External Rectifier Required

DB
(TOP VIEWI

SERIES IN1
REF
SW REG IN2
SW CURRENT
CONTROL

2
3

4

7
6
5

OUTPUT
GND (PWRI
SW IN
GND

description
The TL499A is a monolithic integrated circuit designed to provide a wide range of adjustable regulated
supply voltages. The regulated output voltage is adjustable from 2.9 V to 30 V by adjusting two external
resistors. When the TL499A is ac coupled to line power through a step-down transformer, it operates
as a series dc voltage regulator to maintain the regulated output voltage. With the addition of a backup
battery of from 1.1 V to 10 V, an inductor, a filter capacitor, and two resistors, the TL499A will operate
as a step-up switching regulator during an ac-line failure.
The adjustable regulated output voltage makes the TL499A useful for a wide range of applications. Providing
backup power during an ac-line failure makes the TL499A extremely useful as backup power in
microprocessor memory applications.
The TL499A is characterized for operation from - 20°C to 85 °C.

functional block diagram
BLOCKING

~

__~~~~__~__-*__~~___________1~8~) OUTPUT

....._'V\I'.---l____________..:.17;.:.)

GND (PWR)

~~~~~~~~-----------i------------..:.(4~)SWCURRENT
CONTROL

+
1-__+

__.......;1-2'-) REF

SERIES":'(';':')----~~--lM-----I
IN1

(5)

GND

PRODUCT PREVIEW ..... m......ntain I.'.rmlti••
a. pred.cts in the formati. . .r design ~hl.e of
development, Charloterilti. dltl •• ~ other

=at:::"r~':t ~i:c.W',:I~r T::.:~::::;=
prHuett withoUt notiGL

Copyright © 1984. Texas Instruments Incorporated

TEXAS . "

INSTRUMENTS
POST OFFICE BOX 655012 • DALLAS, TEXAS 75265

3-13

TL499AC
WIDE-RANGE POWER SUPPLY CONTROLLER
absolute maximum ratings over operating free-air temperature range (unless otherwise noted) (see
Note 1)
Output voltage, Vo. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 35 V
Input voltage, series regulator, VI1 ............................................. 35 V
Input voltage, switching regulator, VI2 .......................................... 10 V
Diode (blockingl reverse voltage ............................................... 35 V
Diode (blocking) forward current . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 1 A
Power switch current (at SW IN, pin 6) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 1 A
Continuous total power dissipation. . . . . . . . . . . . . . . . . . . . . . . . . . .. See Dissipation Rating lable
Operating free-air temperature range . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. - 20°C to 85 °C
Storage temperature range ......................................... - 65°C to 150°C
Lead temperature 1,6 mm (1/16 inch) from case for 10 seconds ...................... 260°C
NOTE 1. All voltage values are with respect to network ground terminal.
DISSIPATION RATING TABLE
PACKAGE

TA :$ 25 DC
POWER RATING

D

825 mW

P

1000 mW

DERATING FACTOR
ABOVE TA - 25 DC
6.6 mW/DC
8 mW/DC

TA - B5 D C
POWER RATING
429mW
520mW

recommended operating conditions

"o...

MIN
2.9

NOM

MAX
30

UNIT
V

4.5
1.1

32
10

V
V

1.2

28.9

V

100

mA

500

mA

..

Output voltage. Vo
Input voltage, series regulator, VI1

;

Continuous output current, 10
Power switch current (at SW IN, pin 6)

C;'
~

Current limiting resistor. RCL

150

1000

11

Capacitor, filter
Capacitor pass
Inductor, l (rin < 0.1 III
Operating freeMair temperature, TA

100

470

I'F
pF

150

pH
DC

Q.

C

n

"<
en

Input voltage, switching regulator, VI2
Input-to-output differential voltage, switching regulator, VO-VI2 (see Note 21

0.1

I

50
-20

NOTE 2. When operating temperature range is TA
IlV = Va - V12.

3-14

:$

70 DC,I!N ;" 1.2V. When operating temperature range is TA

TEXAS . "

INSTRUMENTS
POST OFFICE BOX 655012 • DALLAS, TEXAS 75265

85
:$

85 DC,I!N ;" 1.9V.

TLC77011, TL77051, TL77211, TL77251
LinCMOSTM SUPPLY VOLTAGE SUPERVISORS
03221. JANUARY 1989

•

Power-On and Supply Drop-Out Reset
Generator

•

Low Supply Current .•. Maximum 80 p.A

•

Reset Outputs Defined from l-V Supply
Voltage

NC[]8
RESIN 2
7
CT 3
6
GNO 4
5

•

Wide Supply Voltage Range ... 3 V
to 16 V

NC-No internal connection

D. JG. OR P PACKAGE
(TOPVIEWI

•

Precision Temperature-Compensated
Threshold Voltage

•

True and Complement Open-Drain or PushPull Outputs

•

Externally Adjustable Pulse Duration

•

Pin-Compatible Improved Low-Power
Versions of TL7702A and TL7705A

VOO
SENSE
RESET
RESET

description
The LinCMOS'" TLC77_ series of supply voltage supervisors (SVS) are low-power integrated circuits
designed for use as reset controllers in microprocessor and logic systems. During system power-up. the
SVS tests the supply voltage level via the SENSE input. If it is below the nominal value. the RESET and
RESET outputs are held high and low. respectively. The reset outputs reach their active reset levels when
the power supply voltage to the SVS has increased to 1 V.
To ensure a full reset period after the monitored supply voltage reaches its nominal value. the SVS delays
the return of the RESET and RESET outputs to their low and high levels. respectively. by an internal time
delay td. This time delay is determined by an external capacitor connected from the CT input to GND and
is of duration td = 275 x CT p.s. where CT is in nF.
If at any time the supply voltage drops below its nominal value. the reset outputs will immediately become.
and remain. in the reset active state until the supply voltage has returned to its nominal value and the
reset period has elapsed.
Holding the RESIN input low keeps the reset outputs in their active (reset) states. The RESIN input can
be used to provide a debounced input for a reset switch or a cascade input for the wired-OR reset outputs
of several SVSs in multiple supply systems.

...
U

:::::J

.

"C

o

Q.

To prevent functional failures. these devices have internal electrostatic discharge (ESD) protection circuits
rated at 2 kV. However. care should be exercised in handling these devices as exposure to ESD may result
in a degradation of the device parametric performance.
These devices are characterized for operation from - 40 °C to 85°C.
DEVICE FEATURES
Threshold voltage

Open-drain outputs
Push-pull outputs

LinCMOS is a trademark of Texas Instruments Incorporated.

PRODUCT PREVIEW documents contain information

on products in the formative or design ~h8S8 of
development. Characteristic data anil othar

l::t dt-:.si:B=::I~rT3i~:~~:::7:':

~::~::t~~s

products without notice.

TEXAS

~

INSTRUMENTS
POST OFFICE BOX 655012 • DALLAS, TEXAS 75265

Copyright @ 1989. Texas Instruments Incorporated

3-15

TLC7701l, TLC77051, TLC77211, TLC77251
LinCMOS'" SUPPLY VOLTAGE SUPERVISORS
functional block diagram

VDD~(8~1---------------------------------------4~----------------~
VOLTAGE

ICT = 5,.A

REFERENCE
=1.3 V
CT (31
SENSE 171

tR2

itiifJ .:.;12"11t--H:1

GND~(4~1~------------------------------------__----e-------------~
."

e;

Q.
C

a

tTLC7701, TLC7721: Rl = 0 Il NOM, R2 = Open .
TLC7705, TLC7725: Rl = 1.37 Mil NOM, R2 = 545 kll NOM.

schematics of inputs and outputs
TYPICAL OF ALL OUTPUTS

EQUIVALENT OF EACH INPUT

."

;

VDD

<
i'
==

U)

1---INPUT--....-------'I--.-'lNV--.....- J

~

-

-

--

-£

VDD

~

i.J

P-MOSFET NOT PRESENT
IN TLC770_ IiESfi'
OUTPUT
OUTPUT

~

N-MOSFET
NOT PRESENT IN
TLC770_ RESET
OUTPUT

3-16

TEXAS . "

INSTRUMENlS
POST OFFICE BOX 655012 • DALLAS. TEXAS 75265

THICKFIELD
TRANSISTOR

TLC7701L TLC7705L TLC7721L TLC77251
LinCMOS"" SUPPLY VOLTAGE SUPERVISORS
typical operating sequence

I

VT\

SENSE y , " V T

I

RESIN~
RESET

1 V

I

\

VDDd
1 V

I

I

I

I

I

I
I

-I-VT

I

i

I

I
I

U

I

:.

n

RESET 1Vl r - t d j

I

I
I

=1.5 V

I
I

CT

--.....L.r._ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

OV

absolute maximum ratings over operating free-air temperature range (unless otherwise noted)
Supply voltage. VDD (see Note 1) ............................................ " 18 V
Input voltage range at RESIN and SENSE ................................ -0.3 V to VDD
High-level output current at RESET . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. - 5 mA
Low-level output current at RESET . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 5 mA
Continuous total dissipation ................................. see Dissipation Rating Table
Operating free-air temperature range .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. - 40 DC to 85°C
Storage temperature range ........................................ - 65 DCC to 150°C
Lead temperature 1.6 mm (1/16 inch) from case for 10 seconds: D or P package. . . . . . . .. 260°C
Lead temperature 1.6 mm (1/16 inch) from case for 60 seconds: JG package ........... 300°C

•

NOTE 1: All voltage values are with respect to the network ground terminal.
DISSIPATION RATING TABLE
PACKAGE

TA :s 25°C
POWER RATING

D

725mW

JG

825 mW
1000 mW

P

DERATING FACTOR
ABOVE TA - 25°C
5.8 mW'oC
6.6 mW'oC

TA - 85°C
POWER RATING

8.0 mW'oC

377mW
429 mW
520mW

recommended operating conditions
MIN

MAX

Supply voltage. VOD t (see Note 2)

3

16

High-level input voltage at~. VIHt

2

V
V

0.6

V

VOD
-2

mA

Low-level input voltage at

RElrnii.

VIL t

Input voltage at SENSE input. VI

0

High-level output current at RESET. IOH
Low-level output current at~. IOL

4
-40

Operating free-sir temperature range, T A

85

UNIT

V
mA
DC

tOutputs are in a reset state above a VOO of 1 V.
tAn unused RESIN input should be tied to VOO.
NOTE 2: The minimum operating supply voltage will be equal to the voltage at the SENSE input for the TLC77_5.

TEXAS . "

INSTRUMENTS
POST OFFICE BOX 655012 • DALLAS, TEXAS 75265

3-17

TLC7701L TLC7705L TLC7721L TLC77251
LinCMOS"" SUPPLY VOLTAGE SUPERVISORS
electrical characteristics over ranges of recommended operating conditions (unless otherwise noted)
TEST CONDlTlONSt

PARAMETER

High-level output voltage RESET

VOH

Low-level output voltage RESET

VOL

High-level output voltage at RESET
VOH(ST)

defined at start-up
Low-level output voltage at

VOL(ST)

defined at start-up

Hysteresis at SENSE input
Vhys

Isee Note 3)

II

Input current at RESIN

II

Input current at SENSE

..
o

"D

IOL
100

VOO-O.l

TLC77

at RESE'f
Low-level output current
at RESET
Supply current

0.1
VOO-O.l

=0

0.8
1.303

V

to 16 V, TA = 25°C

1.290

to 16 V, TA = 25°C
to 16 V

4.505

4.55

1.316
4.59

1.277
4.46

1.303
4.55

1.329
4.64

= 3V to

5

16 V, TA = 25°C

to VOO

0.5

2

0.5

2

pA
pA

5

=

TLC77_5 VOO = 16 V, Vo

= 0,

16 V, VI = VOO
VI

=

VOO

All inputs at VOO, No load

V

mV

15

1 VI - 0 to VOO
5 VI = 5 V

TLC77_5 VOO = 16 V, Vo

V
V

VOO - 1 V to 3 V,
RL = 4.7 kll to VOO§

to 16 V

UNIT

V
0.4

IOH = 20 pA
VOO = 1 V to 3 V,
RL = 500 kll to GNO§

VI

High-level owtput current
IOH

IOH = 20pA
IOH = 4mA

TLC77_1
VOO
TLC77_5
TLC77

MAX

TYP*

VOO-1.S

TLC77_1 VOO = 3 V
TLC77_5 VOO = 5 V
TLC77_1 VOO - 3 V
TLC77 5 VOO - 5 V

Threshold voltage
at SENSE input

VT

RESE'f

MIN

IOH=2mA

25

1

pA

-1

pA

80

pA

Co

c

...n
"D

switching characteristics over full range of recommended operating conditions (unless otherwise noted)
TEST CONDITIONSt

PARAMETER
Pulse duration, SENSE

MIN

VIH = VTtyp Xl.08, VIL = VTtypxO.92

500
400

CD'

VIH = 4.8 V, VIL = 0.4 V
Time delay, SENSE high to reset outputs inactive CT = 1 nF, TA = 25°C, See Note 4
td
VOO = 5 V, RL = 4.7 kll, CL = 100 pF
tpdl Propagation delay, SENSE to reset active

(I)

tpd2 Propagation delay, RESIN to reset active

CD

<
~

tw1

tw2 Pulse duration, RESIN

trl
tfl
tr2
tf2
t r3
tf3

TYP*

MAX

UNIT

ns
ns
0.35

ns
0.6

ps

0.4

ps

Rise time, RESET and RESET TLC7721, TL7725

200

ns

Fall time, RESET and RESET

TLC7721, TL7725

200

ns

Rise time, RESET
Fall time, RESET

TLC7701, TL7705
TLC7701, TL7705

200

ns

1

2

ps

Rise time, RESE'f
Fall time, RESET

TLC7701, TL7705

1

2
200

ps
ns

CT

=

1 nF,TA

= 25°C

VOO = 5 V, RL = 4.7 kll, CL = 100 pF

TLC7701, TL7705

tAli characteristics are at 10 nF between CT and GND.

*All typical values are at TA = 25°C.

§Supply voltage slew rate should not exceed 30 Vips.
NOTES: 3. Hysteresis is the difference between the positive-going input threshold voltage IVT +) and the negative-going input threshold
voltage (VT _ ).
4. This parameter is measured in normal operation after the initial power-up reset. See typical operating sequence.

3-18

TEXAS ~

INSTRUMENTS
POST OFFICE BOX 655012 • DALLAS, TEXAS 75265

TLC7701L TLC7705L TLC7721L TLC77251
LinCMOSTM SUPPLY VOLTAGE SUPERVISORS
PARAMETER MEASUREMENT INFORMATION

FIGURE 1. SWITCHING VOLTAGE WAVEFORMS

PRINCIPLES OF OPERATION
The internal configuration, shown in the functional block diagram, comprises a precision SENSE input
comparator, a precision voltage reference, a current source, a discharge NMOS transistor, an RS latch,
and an output comparator that drives the reset outputs. Logic input RESIN feeds the input of another
comparator.
The SENSE input comparator is used to monitor a chosen supply voltage. The reset outputs of TLC77_5
trip at an input voltage threshold level, preset by an internal high-impedance potential divider, equalling
a 10% drop in a 5-V supply. The reset outputs of TLC77_1 trip at any user-defined supply voltage threshold
level set by an external potential divider connected directly to the input of the SENSE comparator. The
TLC77 _1 SENSE comparator has a threshold level at its input set by the internal reference voltage of
nominally 1.3 V (see electrical characteristics table values).
The current source, discharge NMOS transistor, and RS latch provide the retriggerable reset timing function
with an external capacitor connected between CT and GND. The internal output comparator monitors the
capacitor voltage and controls the state of the reset outputs.

II
en
~

Q)

..

'S
Q)
a..

....U
j

..

"C

o

a..

The TLC770_ RESET and RESET outputs are open drain and require resistors to define the non-reset
condition by pulling-up to VDD or pulling-down to GND, respectively. Open-drain reset outputs allow the
TLC770_ to be used in applications where wired-AND/OR is required. An example is microprocessors
with reset inputs that also act as system reset outputs under software control. When this is not required,
the push-pull outputs of TLC772_ are more appropriate. These use internal PMOS and NMOS transistors,
respectively, on RESET and RESET outputs to define an active non-reset condition, saving an external pull-up
resistor.
In operation, when the monitored supply voltage has reached the SVS threshold level VT, an internaI5-,.A
current source starts to charge the external capacitor CT. The reset outputs remain in their active reset
state until the voltage across CT reaches an internaI1.3-V reference voltage. The output comparator then
returns the reset outputs to their non-reset states. The internal current source continues to charge CT
until a clamp level of 1.5 V is reached. Supply voltage drop-outs that make the SENSE input fall below
VT cause capacitor CT to be discharged via the NMOS transistor. The input of the output comparator
then falls below its reference level and the reset outputs are switched to an active reset state. A full reset
timing pulse duration is ensured by discharging CT to the same voltage level irrespective of the input SENSE

TEXAS .."

INSTRUMENTS
POST OFFICE BOX 655012 • DALLAS, TEXAS 75265

3-19

TLC7701l, TLC77051, TLC77211, TLC77251
LinCMOSTM SUPPLY VOLTAGE SUPERVISORS
PRINCIPLES OF OPERATION
pulse duration above the minimum specified. This is achieved by detecting the CT capacitor voltage level
and only releasing the RS latch when the capacitor has reached 0.5 V. A feedback action maintains this
value. At power-up, when CT is fully discharged, the reset pulse duration (tw) is approximately twice the
duration of a reset pulse duration obtained when VOO is established and TLC77_ is in normal operation.
Setting the RESIN input low has the same effect as the SENSE input falling below VT. If the RESIN input
is unused, it should be tied to VOO. The RESIN input uses a comparator with a nominal threshold voltage
of 1.3 V, and can be used to monitor supply voltages with an external potential divider in the manner
of the TLC77 _1 SENSE input but with less accuracy. For greater precision, the wired-OR RESET outputs
of several TLC770_ devices used to monitor a systems multiple supply voltages can be fed into the RESIN
input of a master SVS whose output provides the overall system reset function.

•

When their supply voltage approaches the nominal TTL threshold of 1.4 V during power-up, most logic
devices start to become internally biased. Special bias circuits have been added to the TLC77 _ RESET
and RESET output transistor to ensure that these outputs are reset active when VOO reaches 1 V. The
RESET output will not exceed the lower TTL input threshold of 0.8 V. The only limitation is the initial rate
of rise of supply voltage, which if greater than 30 V/p.s may not allow sufficient time for the RESET and
RESET MOS output transistors to be fully turned on. This is caused by their gate circuit time-constants
being initially higher at very low supply voltages. The effect is for the RESET output to follow the supply
voltage increase for several ns. This is not a problem in practice because power supplies usually assume
a current sourcing mode at start-up that, when feeding into an output smoothing capacitor, limits the rate
of rise of output voltage.
When using the TLC77 _1 , low-power applications require high-value external resistors to provide a userdefined external threshold level. To achieve minimum propagation delay, it may be necessary to provide
compensation by means of a capacitor across the series resistor (the input capacitance of the SENSE
comparator is typically 8 pF). Care should be taken that over compensation, which would cause triggering
on noise, does not occur. Conversely, if it is desired to reduce susceptibility to noise, a capacitor can be
placed across the input. For the TLC77 _5, a low-value resistor in series with the SENSE input is required
to achieve this function.
Capacitor CT should have a leakage current substantially below the 5-p.A charge current. This may rule
out the use of electrolytic capacitors.
TLC77 _ internal parameter values referred to in this description are nominal design values.

3-20

TEXAS ~

INSTRUMENTS
POST OFFICE BOX 655012 • DALLAS, TeXAS 75265

UC2842, UC2843, UC2844, UC2845
UC3842, UC3843, UC3844, UC3845
CURRENT·MODE PWM CONTROLLERS
03175, JANUARY 1989

•

o PACKAGE

Optimized for Off· Line and DC-to-DC
Converters

•

Low Start-Up Current « 1 mAl

•

Automatic Feed-Forward Compensation

•

Pulse-by-Pulse Current Limiting

•

Enhanced Load·Response Characteristics

•

Undervoltage Lockout with Hysteresis

•

Double Pulse Suppression

•

High-Current Totem-Pole Output

•

Internally Trimmed Bandgap Reference

(TOP VIEWI

REF
NC

COMP
NC
VFB
NC
ISENSE
NC
RT/CT

VCC
VC
OUTPUT
GND
POWER
GROUND

NC-No internal connection

•

500·kHz Operation

•

Error Amplifier with Low Output Resistance

•

Designed to be Interchangable with Unitrode
UC2842 and UC3842 Series

u
P PACKAGE
(TOPVIEWI

COMP
VFB
ISENSE
RT/CT

8

2
3

4

7

6
5

REF
VCC
OUTPUT
GND

•

description
The UC2842 and UC3842 series of control integrated circuits provide the features that are necessary to
implement off-line or dc-to-dc fixed-frequency current-mode control schemes with a minimum number of
external components. Internally implemented circuits include: undervoltage lockout (UVLO) featuring a
start-up current of less than 1 mA, a precision reference trimmed for accuracy at the error amplifier input,
logic to ensure latched operation, a pulse-width modulation (PWM) comparator (which also provides currentlimit control), and a totem-pole output stage designed to source or sink high peak current. The output
stage, suitable for driving N-channel MOSFETs, is low when it is in the off state.

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The primary difference between the UC2842-series devices and the UC3842-series devices is the ambient
operating temperature range. The UC2842-series devices operate between - 25°C and 85 °C; the
UC3842-series devices operate between OOC and 70°C, Major differences between members of these
series are the undervoltage lockout (UVLO) thresholds and maximum duty cycle ranges. Typical UVLO
thresholds of 16 V (on) and 10 V (off) on the UC_842 and UC_844 devices make them ideally suited
to off-line applications. The corresponding typical thresholds for the UC_843 and UC_845 devices are
8.4 Von and 7.6 V off. The UC_842 and UC_843 devices can operate to duty cycles approaching 100%.
A duty cycle range of 0 to 50% is obtained by the UC_844 and UC_845 by the addition of an internal
toggle flip-flop, which blanks the output off every other clock cycle.

"t:I

Copyright @ 1989, Texas Instruments Incorporated

TEXAS . "
INSTRUMENTS
POST OFFICE BOX 855012 • DALLAS. TEXAS 75265

3-21

UC2842, UC2843, UC2844, UC2845
UC3842, UC3843, UC3844, UC3845
CURRENT·MODE PWM CONTROLLERS
absolute maximum ratings over operating free·air temperature (unless otherwise noted)
Supply voltage (see Note 1) (ICC < 30 mAl . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. Self Limiting
Analog input voltage (VFB and ISENSE terminals) ......................... -0.3 V to 6.3 V
Voltage on output pin ....................................................... 35 V
Voltage on VC pin (14-pin package) ............................................ 35 V
Supply current, ICC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 30 mA
Output current. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. ± 1 A
Error amplifier output sink current. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 10 mA
Continuous power dissipation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. see Dissipation Rating Table
Output energy Icapacitive load) ................. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 5 p.J
Storage temperature range ......................................... - 65°C to 150°C
Lead temperature, 1,6 mm (1/16 inch) from case for 10 seconds ..................... 260°C
NOTE 1: All voltages are with respect to the device GND terminal.
DISSIPATION RATING TABLE
PACKAGE

•..

TA s 2S·C
POWER RATING

D

p

950 mW
1000mW

DERATING FACTOR
ABOVE TA - 2S·C
7.6 mW/·C
8.0 mW/·C

TA - 70·C
POWER RATING

TA - 8S·C
POWER RATING

608mW
640mW

494mW
520 mW

recommended operating conditions

""0

UC284

o

MIN

C

Supply voltage, VCC and VC

..

""0

Average output current, 10
Reference output current

200
-20

200
-20

Frequency range

500

CD

Operating free-air temperature, T A

SOO
70

n

r+

<
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~

til

NOM

UC384
MAX
30

Q.

-25

85

MIN

NOM

0

MAX
30

UNIT
V
mA
mA
kHz
·C

electrical characteristics, VCC .. 15 V (see Note 2). RT = 10 kO. CT = 3.3 nF. TA - full range
(unless otherwise specified)
reference section
PARAMETER
Output voltage
Line regulation

load regulation

UC284_

TEST CONDITIONS
10

=

1 mA, T J

= 25·C

TYP

MAX

MIN

TYP

MAX

4.95

5
6

5.05

4.9

5

Output noise voltage

Output voltage long-term
drift

VCC = 12 V to 25 V,
10 = 1 mAto20mA
f = 10 Hz to 10 kHz, TJ

6

5.1
20

V
mV

6

6

25

mV

0.2

0.4

0.2

0.4

mV/·C

After 1000 h at TA

=

4.9
=

5.1

25·C

-30

5

25
-180

TEXAS ",

INSTRUMENTS
POST OFFICE BOX 655012 • DALLAS, TEXAS 75265

5.18

-30

V
~V

50

-100

NOTE 2: Adjust VCC above the start threshold before setting it to 15 V.

3-22

4.82

50

125·C

Short-circuit output current

UNIT

20
25

VCC = 12Vto25V
10 = 1 mAto20mA

Temperature coefficient of

output voltage
Output voltage with worstcase variation

UC384_

MIN

5

25

m.V

-100

-180

mA

'tII

~_D_e_S_ig_n_C__O_n_Si_d_e_ra_t_io_n_s____________

4-1

Contents
Page
Voltage Regulators. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..
Switching Power Supply Design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..
TL77XXA Supply Voltage Supervisors ...........................
500-W/BO-A Switching Power Supplies ..........................

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4-2

4-3
4-61
4-141
4-177

Voltage Regulator Circuits

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TEXAS
INSTRUMENTS

4-3

IMPORTANT NOTICE
Texas Instruments (TI) reserves the right to make changes to or
to discontinue any semiconductor product or service identified
in this publication without notice. TI advises its customers to
obtain the latest version of the relevant information to verify,
before placing orders, that the information being relied upon is
current.
TI warrants performance of its semiconductor products to current
specifications in accordance with Tl's standard warranty. Testing
and other quality control techniques are utilized to the extent TI
deems necessary to support this warranty. Unless mandated by
government requirements, specific testing of all parameters of
each device is not necessarily performed.

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TI assumes no liability for TI applications assistance, customer
product design, software performance, or infringement of patents
or services described herein. Nor does TI warrant or represent that
any license, either express or implied, is granted under any patent
right, copyright, mask work right, or other intellectual property
right of TI covering or relating to any combination, machine, or
process in which such semiconductor products or services might
be or are used .

Copyright © 1989, Texas Instruments Incorporated

Contents
Title

Page

Basic Regulator Theory .......................................... .

4-9

Voltage Regulator Components . ................................... .

4-9

Reference Element ...............................................
Sampling Element ................................................
Error Amplifier ..................................................
Control Element .................................................

.
.
.
.

4-9
4-10
4-10
4-10

Regulator Classifications ......................................... .

4-11

Series Regulator ................................................. .
Shunt Regulator .................................................. .
Switching Regulator .............................................. .

4-11
4-12
4-13

Major Error Contributors . ....................................... .

4-14

Regulator Reference Techniques ....................................
Zener Diode Reference .......................................
Constant-Current Zener Reference .............................
Band-Gap Reference .........................................
Sampling Element ................................................
Error Amplifier Performance .......................................
Offset Voltage ..............................................
Offset Change with Temperature ...............................
Supply Voltage Variations ....................................

.
.
.
.
.
.
.
.
.

4-14
4-14
4-14
4-16
4-18
4-19
4-19
4-19
4-20

Regulator Design Considerations .................................. .

4-21

Positive vs Negative Regulators .................................... .
Fixed vs Adjustable Regulators ..................................... .
Dual-Tracking Regulator .......................................... .
Series Regulator ................................................. .
Floating Regulator ........................................... .
Shunt Regulator .................................................. .
Switching Regulator .............................................. .
Fixed-an-Time, Variable Frequency ............................ .
Fixed-Off-Time, Variable Frequency ......................•.....
Fixed-Frequency, Variable Duty Cycle .......................... .

4-22
4-23
4-24
4-24
4-25
4-27
4-28
4-30
4-31
4-32

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Contents (Continued)
Regulator Safe Operating Area ....................................

4-33

Regulator SOAConsiderations ......................................
,
Input Voltage. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Load Current . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Power Dissipation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Output Voltage of an Adjustable-Voltage Regulator. . . . . . . . . . . . . . . .
External Pass Transistor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Safe Operating Protection Circuits ...................................
Reverse Bias Protection .......................................
Current Limiting Techniques . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Series Resistor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Constant-Current Limiting. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Fold-Back Current Limiting. . . . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . .

4-33
4-33
4-34
4-34
4-34
4-34
4-35
4-35
4-35
4-36
4-37
4-39

Three Terminal Regulators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

4-41

Stabilization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Fixed Dual Regulators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Series Adjustable Regulator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

4-41
4-42
4-43

Layout Guidelines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

4-44

CD

Layout Design Factors ............................................
Input Ground Loop ..........................................
Output Ground Loop .........................................
Remote Voltage Sense .......................................

.
.
.
.

4-44
4-44
4-45
4-46

cS'

Input Supply Design ............................................. .

4-46

o
o

Transformer/Rectifier Configuration ................................. .
Capacitor-Input Filter Design ...................................... .

4-46
4-48

Low Drop-Out Voltage Regulator Design Considerations ............. .

4-53

Thermal Considerations in Design of Power Supplies ................ .

4-55

Introduction ..................................................... .
Basic Thermal Circuits and Symbols ................................ .
Thermal Design Examples ......................................... .
General Suggestions for Efficient Thermal Management ................ .
Conclusion ...................................................... .

4-55
4-55
4-58
4-60
4-60

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4-6

List of Illustrations
Figure

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33

Title

Basic Regulator Block Diagram ............................. .
Control Element Configurations ............................. .
Basic Series Regulator .................................... .
Basic Shunt Regulator ..................................... .
Basic Switching Regulator ................................. .
Basic Zener Reference .................................... .
Zener Reference Model ................................... .
Constant-Current Zener Reference .......................... .
Band-Gap Reference ...................................... .
RlIR2 Ladder Network Sampling Element .................... .
Amplif~r Model Showing Input Offset Voltage Effect .......... .
Amplifier Model Showing Common-Mode Voltage ............. .
Conventional Positive/Negative Regulator .................... .
Positive Regulator in Negative Configuration .................. .
Negative Regulator in Positive Configuration .................. .
Dual-Tracking Regulator .................................. .
Series Regulator ......................................... .
Floating Regulator ........................................ .
Floating Regulator as a Constant-Current Regulator ............ .
Shunt Regulator .......................................... .
Output Voltage vs Shunt Current of a Shunt Regulator ......... .
Switching Voltage Regulator Modes ......................... .
Variation of Pulse Width vs Load ........................... .
Frequency vs Load Current for Fixed On-Time SVR ........... .
Frequency vs Load Current for Fixed Off-Time SVR .......... .
Switching Voltage Regulator Configurations .................. .
Reverse Bias Protection ................................... .
Series Resistance Current Limiter ........................... .
Performance Characteristics of a Series Resistance
Current-Limited Regulator ................................. .
Constant-Current Limit Configuration ........................ .
Constant-Current Limiting for External Pass
Transistor Applications .................................... .
Constant-Current Limiting ................................. .
Fold-Back Current Limiting ................................ .

Page

4-9
4-10
4-11
4-12
4-13
4-14
4-15
4-15
4-16
4-18
4-20
4-20
4-22
4-22
4-23
4-24
4-24
4-25
4-27
4-27
4-28
4-28
4-30
4-31
4-32
4-32
4-35
4-36

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4-37
4-38
4-38
4-39
4-40
4-7

List of Illustrations (Continued)
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51

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4-8

Fold-Back Current Limit Configuration .......................
Fold-Back Current Limit Safe Operating Area. . . . . . . . . . . . . . . . . .
Positive Regulator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Negative Regulator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Regulated Dual Supply . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Positive Adjustable Series Regulator . . . . . . . . . . . . . . . . . . . . . . . . . .
Circuit Layout Showing Error Contributions . . . . . . . . . . . . . . . . . . .
Proper Regulator Layout ...................................
Input Supply. . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . . . .. .. . . .
Input Supply Transformer/Rectifier Configurations. . . . . . . . . . . . . .
Rectifier Output-Voltage Waveforms. . . . . . . . . . . . . . .. . . . .. .. . . .
Relation of Applied Alternating Peak Voltage to Direct
Output Voltage in Half-Wave Capacitor-Input Circuits.. . . .. .. . . .
Relation of Applied Alternating Peak Voltage to Direct
Output Voltage in Full-Wave Capacitor-Input Circuits. . . . . . . . . . .
Relation of RMS and Peak-to-Average Diode Current in
Capacitor-Input Circuits. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Root-Mean-Square Ripple Voltage for Capacitor-Input Circuits. . . .
Typical Response Curves for the TL750MXX Series. . . . . . . . .. . .
Semiconductor Thermal Model ..............................
Basic Semiconductor Heat Sink Steady State Thermal Circuit . . . . .

4-40
4-41
4-42
4-42
4-43
4-43
4-45
4-46
4-47
4-47
4-48
4-49
4-50
4-51
4-52
4-54
4-56
4-57

Basic Regulator Theory
The function of every voltage regulator is to convert a dc input voltage into a specific,
stable, dc output voltage and maintain that voltage over a wide range of load current and
input voltage conditions. To accomplish this, the typical voltage regulator (Figure 1) consists
of:
1. A reference element that provides a known stable voltage level, (VREF)
2. A sampling element to sample the output voltage level
3. An error-amplifier element for comparing the output voltage sample to the
reference and creating an error signal.
4. A power control element to provide conversion of the input voltage to the
desired output level over varying load conditions as indicated by the error
signal ..
INPUT
VOLTAGE

REGULATED
OUTPUT
VOLTAGE

CONTROL
ELEMENT

FEEDBACK
S

E
L
E
M
E
N
T

A
M

VREF

P
L
N
G

-

-

Figure 1. Basic Regulator Block Diagram
Although actual circuits may vary, the three basic regulator types are series, shunt,
and switching. The four basic functions listed above exist in all three regulator types.

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Voltage Regulator Components
Reference Element
The reference element forms the foundation of all voltage regulators since output
voltage is directly controlled by the reference voltage. Variations in the reference voltage
4-9

will be interpreted as output voltage errors by the error amplifier and cause the output
voltage to change accordingly. To achieve the desired regulation, the reference must be
stable for all variations in supply voltages and junction temperatures. There are several
common techniques which can be used to solve design problems using integrated circuit
regulators. Many of these techniques are discussed in the section of the text that outlines
error contributions.

Sampling Element
The sampling element monitors the output voltage and converts it into a level equal
to the reference voltage. A variation in the output voltage causes the feedback voltage
to change to a value which is either greater or less than the reference voltage. This voltage
difference is the error voltage which directs the regulator to make the appropriate response
and thus correct the output voltage change.

Error Amplifier
The error amplifier of an integrated circuit voltage regulator monitors the feedback
voltage for comparison with the reference. It also provides gain for the detected error
level. The output of the error amplifier drives the control circuit to return the output to
the preset level.

Control Element
All the previous elements discussed remain virtually unaltered regardless of the type
regulator circuit. The control element, on the other hand, varies widely, depending upon
the type of regulator being designed. It is the element that determines the classification
of the voltage regulator; series, shunt, or switching. Figure 2 illustrates the three basic
control element configurations, each of which is discussed in detail. These elements
contribute an insignificant amount of error to the regulator's performance. This is because
the sampling element monitors the output voltage beyond the control element and
ILOAD.

R

r--'
VI

~~J
ILOAD

Vo

Vo

•

=VI -(RSIIL

(a)

,

VI

RS

SERIES

IsE

Vo

L
VI

I
IRs

.J

-

Vo ~ VI - R ilL + lSI

(b) SHUNT

VO=VI

ton + toff
(c) SWITCHING

Figure 2. Control Element Configurations

4-10

ton

1

compensates for its error contributions. However, the control element directly affects
parameters such as minimum input-to-output voltage differential, circuit efficiency, and
power dissipation.

Regulator Classifications
Series Regulator
The series regulator derives its name from its control element. The output voltage,
VO, is regulated by modulating an active series element, usually a transistor, that functions
as a variable resistor. Changes in the input voltage, VI, will result in a change in the
equivalent resistance of the series element identified as RS. The product of the resistance,
RS, and the load current, IL creates a changing input-to-output differential voltage,
VI - VO, that compensates for the changing input voltage. The basic series regulator is
illustrated in Figure 3, and the equations describing its performance are listed below.
Vo = VI-(VI- VO)
(VI - VO) = ILRS
Vo = VI-"-ILRS
The change in RS for a changing input voltage is:
AR
4l

_ ..1VI
S -IL

The change in RS for a changing load current:
..1R

S

=

MLRS
IL +..1IL

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Figure 3. Basic Series Regulator

4-"

Series regulators provide a simple, inexpensive way to obtain a source of regulated
voltage. In high-current applications, however, the voltage drop which is maintained across
the control element will result in substantial power loss and a much lower efficiency
regulator.

Shunt Regulator
The shunt regulator employs a shunt control element in which the current is controlled
to compensate for varying input voltage or changing load conditions. The basic shunt
regulator is illustrated in Figure 4.
RS

~

ILOAC

-+
--+
VI~'-------~~------~'---------~-VO

-.,
I
"R. "

'fSHUNT

-...I

•

R2

C
a>
en

cE'

::::I
(')

o

::::I

en

c:a>

......0'

Figure 4. Basic Shunt Regulator
The output voltage, Vo as with the series regulator, is held constant by varying
the voltage drop across the series resistor, RS, by varying the current IS. IS may vary
because ofIL changes or it may vary because of current, I(shunt), through the shunt control
element. For example, as IL increases, I(shunt) decreases to adjust the voltage drop across
RS. In this fashion Vo is held constant.

I»
::::I

en

Vo
IS
Vo

= VI-ISRS
=
=

IL + I(shunt)
VI - RS[IL + I(shunt)1

The change in shunt current for a changing load current is:
.:1I(shunt)

4-12

R1

= - ML

The change in shunt current for a changing input voltage is:
al(shunt)
I

Vo
(shunt) - R(shunt)

Even though it is usually less efficient than series or switching regulators, a shunt
regulator may be the best choice for some applications. The shunt regulator is less sensitive
to input voltage transients; does not reflect load current transients back to the source, and
is inherently short-circuit proof.

Switching Regulator
The switching regulator employs an active switch as its control element. This switch
is used to chop the input voltage at a varying duty cycle based on the load requirements.
A basic switching regulator is illustrated in Figure 5.

en
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",t:l

...m
Q)

"C

Figure 5. Basic Switching Regulator (Step-Down Configuration)
A filter, usually an LC filter, is then used to average the voltage present at its input
and deliver that voltage to the output load. Because the pass transistor is either on (saturated)
or off, the power dissipated in the control element is minimal. The switching regulator
is therefore more efficient than the series or shunt type. For this reason, the switching
regulator becomes particularly advantageous for applications involving large input-to-output
differential voltages or high load-current requirements. In the past, switching voltage
regulators were discrete designs. However, recent advancements in integrated circuit

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4-13

technology have resulted in several monolithic switching regulator circuits that contain
all of the necessary elements to design step-up, step-down, or inverting voltage converters.
The duty cycle may be varied by:
1. maintaining a constant on-time, varying the frequency
2. maintaining a constant off-time, varying the frequency
3. maintaining a constant frequency, varying the on/off times

Major Error Contributors
The ideal voltage regulator maintains constant output voltage despite varying input
voltage, load current, and temperature conditions. Realistically, these influences affect
the regulator's output voltage. In addition, the regulator's own internal inaccuracies affect
the overall circuit performance. This section discusses the major error contributors, their
effects, and suggests some possible solutions to the problems they create.

Regulator Reference Techniques
There are several reference techniques employed in integrated circuit voltage
regulators. Each provides its particular level of performance and problems. The optimum
reference depends on the regulator's requirements.

Zener Diode Reference

•

The zener diode reference, as illustrated in Figure 6, is the simplest technique. The
zener voltage itself, VZ, forms the reference voltage, VREF.
Vl>-------~------__r

...------.VRE F

Figure 6. Basic Zener Reference
This technique is satisfactory for relatively stable supply-voltage and load-current
applications. The changing zener current results in a change in the zener diode's reference
voltage, VZ. This zener reference model is illustrated in Figure 7.

Constant-Current Zener Reference
The zener reference can be refined by the addition of a constant-current source as
its supply. Driving the zener diode with a constant current minimizes the effect of zener
4-14

VI>-------~------~

VREF

= Vz

Vz = VZ' + IZRZ

IZ =

VI-VZ'
R + RZ

VREF = VZ' + RZ (

VI-VZ')
R + RZ

Figure 7. Zener Reference Model
impedance on the overall stability of the zener reference. An example of this technique
is illustrated in Figure 8. The reference voltage of this configuration is relatively independent
of changes in supply voltage and load current.
VREF
IZ

= Vz + VBE(Ql)
= VBE(Ql) +

Res

IB(Ql)

In addition to superior supply voltage independence. the circuit illustrated in Figure 8
yields improved temperature stability. The reference voltage, VREF. is the sum of the
zener voltage (VZ) and the base-emitter voltage of Ql[VBE(Ql)]. A low temperature

U)

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'';:;
VI>----e--------~--_7

...

CO
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s::::

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(.)

s::::

en

...- -.... VREF

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Figure 8. Constant-Current Zener Reference
4-15

coefficient can be achieved by balancing the positive temperature coefficient of the zener
with the negative temperature coefficient of the base-emitter junction of Ql.

Band-Gap Reference
Another popular reference is the band-gap reference, which developed from the highly
predictable emitter-base voltage of integrated transistors. Basically, the reference voltage
is ---------~.-----------~
R

oCD
(II

ce':::J
n

Figure 9. Band-Gap Reference

:::J

The resistor values ofRl andR2 are selected in such a way that the current through
transistors Ql and Q2 are significantly different (11 = 1012). The difference in current
through transistors Q 1 and Q2 also results in a difference in their respective base-emitter
voltages. This voltage differential [VBE(Ql) - VBE(Q2)) will appear across R3. Application
of transistors with sufficiently high gain results in current 12 passing through R3. In this
instance, 12 is equal to:

o

(II

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....o·

m
:::J

(II

VBE(Ql) - VBE(Q2)
R3

:. VREF - VBE(Q3) + [ (VBE(QI) -

4-16

VBE(Q2~:;]

By analyzing the effect of temperature on VREF it can be shown that the difference
between two similar transistors' emitter-base voltages, when operated at different currents
is:
VBE(QI) - VBE(Q2) = k: In

~~

where
k =
T =
q =
I =

Boltzmann's constant
absolute temperature - degrees K
charge of an electron
current

The base-emitter voltage of Q3 can also be expressed as:

YBE(Q3)

= Ygo [1 -

':0

]+

io ]

YBEO[

where

vgo
VBEO

= band-gap potential
= emitter-base voltage at TO

VREF can then be expressed as:
VREF

= Vgo

~ - .1:..1 +VBEO[T 1+R2
~

TOJ

LToJ

R3

Differentiating with respect to temperature yields
dVREF
dT

~ In II
R3 q
12

= _ Vgo+ VBEO+R2
TO

TO

If R2, R3, and II are appropriately selected such that
R2
11
R3 In 12

= [Vgo -

VBEO(Q3)1

c

kT In II
q
12

II
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o

.

'';;

ca
Q)

"C

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cC)

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4-17

where

c = -.9....kTO
and
Vgo

=

1.2 V

the resulting
dVREF
dT

=0

The reference is temperature-compensated.
Band-gap reference voltage is particularly advantageous for low-voltage applications
(VREF = 1.2 V) and it yields a reference level that is stable even with variations in supply
and temperature.

Sampling Element
The sampling element used on most integrated circuit voltage regulators is an RlIR2
resistor divider network (Figure 10), which can be determined by the output-voltage-toreference-voltage ratio.

•

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en

cC"
:::s

oo

Vo =
VREF

1+R1

R2

Since the feedback voltage is determined by ratio and not absolute value, proportional
variations in R1 and R2 have no effect on the accuracy of the integrated circuit voltage
regulator. When proper attention is given to the layout of these resistors in an integrated
circuit, their contribution to the error of the voltage regulator will be minimal. The initial
accuracy is the only parameter affected.

:::s
en

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cr
:::s
en

V l - -....- - - t

CONTROL

I - - -....--_VO

.,

I
IR1

I

I
IR2

I
.J

Figure 10" RlIR2 Ladder Network Sampling Element
4-18

Error Amplifier Performance
If a stable reference and an accurate output sampling element exist, the error amplifier
becomes the primary factor determining the performance of the voltage regulator. Typical
amplifier performance parameters such as offset, common-mode and supply-rejection ratios,
output impedance, and temperature coefficient affect the accuracy and regulation of the
voltage regulator. These amplifier performance parameters will affect the accuracy of the
regulator due to variations in supply, load, and ambient temperature conditions.

Offset Voltage
Offset voltage is viewed by the amplifier as an error signal, as illustrated in Figure 11,
and will cause the output to respond accordingly.
Vo

AVVI

VI

= VREF -

VFB
Vo

VIO - VFB

= VO[Rl~R2]
=

VREF-VIO
1 +[ R2 ]
AV
Rl +R2

If A V is sufficiently large

Vo

= (VREF -

VIO) [1 +:;]
II)

VIO represents an initial error in the output of the integraged circuit voltage regulator.
The simplest method of compensating for this error is to adjust the output voltage sampling
element RlIR2.

Offset Change with Temperature
The technique discussed above compensates for the amplifier's offset voltage and
yields an accurate regulator, but only at a specific temperature. In most amplifiers, the
offset voltage change with temperature is proportional to the initial offset level. Trimming
the output voltage sampling element, does not reduce the offset voltage but merely
counteracts it. At a different ambient tmperature, the offset voltage changes and, thus,
error is again introduced into the voltage regulator. Monolithic integrated circuit regulators
use technology that essentially eliminates offset in integrated circuit amplifiers. With
minimal offset voltage, drift caused by temperature variations will have little consequence.

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4-19

R2

Figure 11. Amplifier Model Showing Input Offset Voltage Effect

Supply Voltage Variations

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The amplifier's power supply and common-mode rejection ratios are the primary
contributors to regulator error which has been introduced by an unregulated input voltage.
In an ideal amplifier, the output voltage is a function of the differential input voltage only.
Realistically, the common-mode voltage of the input also influences the output voltage.
The common-mode voltage is the average input voltage, referenced from the amplifier's
virtual ground (see Figure 12 and the following equations).

cS'
:::s

Vcc+

n
o

:::s

rn

a:CD

Vs

...

Vo

I»

o·:::s
rn

R1
[ ·_
R2 - ]
vo
R1 + R2
R2
vcc-

-

Figure 12. Amplifier Model Showing Common-Mode Voltage
4-20

VCC+ + VCCVirtual ground = -..>."""--'---::---.>.<=-2

VI(av)

VCM ~ ~ [VS+VO(iU~R2) -(vcc+ +VCC-)]
From this relation, it can be seen that unequal variations in either power supply bus
rail will result in a change in the common-mode voltage. The common-mode voltage
rejection ration (CMRR) is the ratio of the amplifier's differential voltage amplification
to the common-mode voltage amplification.
CMRR =

AVD
AVCM

AVD
AVCM = CMRR
That portion of output which is voltage contributed by the equivalent common-mode
input voltage is:
Vo

=

VCMAVCM

=

AVDVCM
CMRR

The equivalent error introduced then is:
COMMON-MODE ERROR

=

VCM
CMRR

The common-mode error represents an offset voltage to the amplifier. Neglecting
the actual offset voltage, the output voltage of the error amplifier then becomes:
Vo

=

VCM)(1+R2
Rl)
( VREF+ CMRR

Using constant-current sources in most integrated circuit amplifiers, however, yields
a high power-supply (common-mode) rejection ratio. This power-supply rejection ratio
is of such a large magnitude that the common-mode voltage effect on Vo can usually be
neglected.

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Regulator Design Considerations
Various types of integrated circuit voltage regulators are available, each having its
own particular characteristics, giving it advantages in various applications. The type of
regulator used depends primarily upon the designer's needs and trade-offs in performance
and cost.
4·21

Positive vs Negative Regulators
This classification of voltage regulators is easily understood; a positive regulator
is used to regulate a positive voltage, and a negative regulator is used to regulate a negative
voltage. However, what is positive and negative may vary, depending upon the ground
reference.
Figure 13 illustrates conventional positive and negative voltage regulator applications
employing a continuous and common ground. For systems operating on a single supply,
the positive and negative regulators may be interchanged by floating the ground reference
to the load or input. This approach to design is recommended only where ground isolation
serves as an advantage to overall system performance.

+VI

IN

OUT

POSITIVE
REGULATOR

IL~

COM

GND

GND

COM
-VI

IN

"
c

-!-IL;>

NEGATIVE
REGULATOR
VREG

+vo

-Vo

OUT
+

/'

Figure 13. Conventional Positive/Negative Regulator

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Figures 14 and 15 illustrate a positive regulator in a negative configuration and a
negative regulator in a positive configuration, respectively.

(")

o

+

::J

o

,/.

CD

IN

....is:
II)

+

o·::J

VI

o

vREG
POSITIVE
REGULATOR
COM

1

\.
OUT*~
IL

G
-Vo

(VI MUST FLOAT)

Figure 14. Positive Regulator in Negative Configuration

4-22

(VI MUST FLOAT)

.-

+
COM

VI
IN

r

NEGATIVE
REGULATOR

"

VREG

+VO

OUT

J:.

G

/' -

+

Figure 15. Negative Regulator in Positive Configuration

Fixed vs Adjustable Regulators
Many fixed three-terminal voltage regulators are available in various current ranges
from most major integrated circuit manufacturers. These regulators offer the designer a
simple, inexpensive method to establish a regulated voltage source. Their particular
advantages are:
1. Ease of use
2. Few ,external components required
3. Reliable performance
4. Internal thermal protection
5. Short-circuit protection.
There are disadvantages. The fixed three-terminal voltage regulators cannot be
precisely adjusted because their output voltage sampling elements are internal. The initial
accuracy of these devices may vary as much as ± 5 % from the nominal value; also the
output voltages available are limited.
Current limits are based on the voltage regulator's applicable current range and are
not adjustable. Extended range operation (increasing ILOAD) is cumbersome and requires
complex external circuitry.
The adjustable regulator may be well suited for those applications requiring higher
initial accuracy. This depends on the complexity of the adjustable voltage regulator.
Additionally, all adjustable regulators use external feedback, which allows the designer
a precise and infinite voltage selection.
The output sense may also be referred to a remote point. This allows the designer
to not only extend the range of the regulator (with minimal external circuitry), but also
to compensate for losses in a distributed load or external pass components. Additional
features found on many adjustable voltage regulators are: adjustable short-circuit current
limiting, access to the voltage reference element, and shutdown circuitry.

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4-23

Dual-Tracking Regulator
The dual-tracking regulator (Figure 16) provides regulation for two power supply
buses, usually one positive and one negative. The dual-tracking feature assures a balanced
supply system by monitoring the voltage on both power supply buses. If either of the
voltages sags or goes out of regulation, the tracking regulator will cause the other voltage
to vary accordingly (A 10% sag in the positive voltage will result in a 10% sag in the
negative voltage.). These regulators are, for the most part, restricted to applications such
as linear systems where balanced supplies offer a definite performance improvement.

0 100

+VI----f

Vo+
DUAL
TRACKING

GND

REGULATOR
-VI----I

>
Q

w
:E
:E

«
a:

50

Cl

0

VO-

a:
l)..
II.

0

0

~

0

50

100

% OF PROGRAMMED VO-

Figure 16. Dual-Tracking Regulator

Series Regulator

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The series regulator is well suited for medium current applications with nominal
voltage differential requirements. Modulation of a series pass control element to maintain
a well-regulated, prescribed, output voltage is a straightforward design technique. Safeoperating-area protection circuits such as overvoltage, fold-back current limiting, and shortcircuit protection are additional functions that series regulators can supply. The primary
disadvantage of the series regulator is its power consumption. The amount of power a
series regulator (Figure 17) will consume depends on the load current being drawn from
the regulator and is proportional to the input-to-output voltage differential. The amount

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:::s

tn

VI----I

SERIES
REGULATOR

I----VO

---+
IL

Figure 17. Series Regulator
4-24

of power consumed becomes considerable with increasing load or differential voltage
requirements. This power loss limits the amount of power that can be delivered to the
load because the amount of power that can be dissipated by the series regulator is limited.
The equations that describe these conditions are listed below. PREG is the power
lost in the regulator, II is the input current, IREG is the regulator current and IL is the
load current. The differential voltage across the regulator is (VI - VO).
PREG
II

= VIII - VOIL
= IREG+IL

Since IL is much greater than IREG
II
PREG

= IL
=

IL (VI - VO)

Floating Regulator
The floating regulator (Figure 18) is a variation of the series regulator. The output
voltage remains constant by changing the input-to-output voltage differential for varying
input voltage. The floating regulator's differential voltage is modulated such that its output
voltage when referenced to its common terminal VO(reg) is equal to its internal reference
(VREF). The voltage developed across the output-to-common terminal is equal to the
voltage developed across Rl(VRI).

II

.r---VDIFF ----,~

o

i

FLOATING
REGULATOR

1

•

VO(REG)

VIIREG)

I

c

•t
VCOM

i1I
....--1
R1

V

R1

Vo

~ R2

+
Figure 18. Floating Regulator

j

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',=
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'mC
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cC)

'm
Q)

c

4-25

VO(reg) = VREF = VRI
VRI = Vo

[Rl~lR2 ]

VO=VREF[I+~J
The common-terminal voltage is:
VCOM = VO-VRI = VO-VREF
The input voltage seen by the floating regulator is:
VI(reg) = VI - VCOM
VI(reg) = VI - Vo + VREF
VI(reg) = VDIFF + VREF
Since VREF is fixed, the only limitation on the input voltage is the allowable
differential voltage. This makes the floating regulator especially suited for high-voltage
applications (VI> 40 V). Practical values of output voltage are limited to practical ratios
of output-to-reference voltages.
R2 =

•

o
Q)

Rl

Vo -1
VREF

The floating regulator exhibits power consumption characteristics similar to that of
the series regulator from which it is derived, but unlike the series regulator, it can also
serve as a current regulator as shown in Figure 19.

en

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::s
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Vo = VREF

[1 +~~ ]

Vo = VL+VO(reg)

c:

VO(reg) = VREF

....CIl

VL = VREF

[1

VL = VREF

[~~]

Q)

S·
::s
en

IL = VLOAD
RL
ILOAD = VREF
RS
4-26

+

~~] - VREF

:--

FLOATING
REGULATOR

I

RS

.

T

VO(REG)

•

•

!I

T
~

~RL

Figure 19. Floating Regulator as a Constant-Current Regulator
Shunt Regulator
The shunt regulator, illustrated in Figure 20, is the simplest of all regulators. It
employs a fixed resistor as its series pass element. Changes in input voltage or load current
requirements are compensated by modulating the current which is shunted to ground through
the regulator.
For changes in VI:

~IZ

For changes in IL: .!lIZ

=

~ VI
RS

= - ~IL
RS

VI

----~~~--~__---------

~
R
E
G
H U
U L
N A

s

Va

1':

T T

a

R

CI)

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Figure 20. Shunt Regulator

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The inherent short-circuit-proof feature of the shunt regulator makes it particularly
attractive for some applications. The output voltage will be maintained until the load current
required is equal to the current through the series element (see Figure 21). Since the shunt
regulator cannot supply any current, additional current required by the load will result
in reducing the output voltage to zero.

4-27

VI-VO
RS
w
C!I
~1-_......;l""_.....1:;"'_ _

IZ

w

...I

o
>

a:
a:

I-

:::>

Q.

I-

u

:::>

z

I-

:::>

:::>

o

:r:

en
VI-VO
RS

o
RS

Figure 21. Output Voltage vs Shunt Current of a Shunt Regulator

The short-circuit current of the shunt regulator then becomes:

Vo
ISC

•

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(II

cE'
;:,

o
VI

RS
Switching Regulator
The switching regulator lends itself primarily to the higher power applications or
those applications where power supply and system efficiency are of the utmost concern.
Unlike the series regulator, the switching regulator operates its control element in an onor off-mode. Switching regulator control element modes are illustrated in Figure 22.

(')

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(II

Vo

Vo

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;:,
(II

ON-STATE

OFF-STATE

Psw=Vsw ISW
Vsw= OV
Psw = OW

Psw=Vswlsw
Isw=O A
Psw=ow

Figure 22. Switching Voltage Regulator Modes
4-28

In this manner, the control element is subjected to a high current at a very low voltage
or a high differential voltage at a very low current. In either case, power dissipation in
the control element is minimal. Changes in the load current or input voltage are compensated
for by varying the on-off ratio (duty cycle) of the switch without increasing the internal
power dissipated in the switching regulator. See Figure 23(a).
For the output voltage to remain constant, the net charge in the capacitor must remain
constant. This means the charge delivered to the capacitor must be dissipated in the load.
IC

IL/-IL

IC

-IL for IL'

IC

IL(pk) - IL for IL = IL(Pk)

=

0
I

The capacitor current waveform then becomes that illustrated in Figure 23(b). The
charge delivered to the capacitor and the charge dissipated by the load are equal to the
areas under the capacitor current waveform.

~Q + = ~ (IL(pk) -IU2 t (VI)
2

IL(pk)

Vc

4Q- IL ['Period - H~~) -~te~~I~(~~)]
By setting
be determined;

~Q

+ equal to ~Q - , the relationship of IL and IL(Pk) for

~Q

= 0 can

IL ~ i IL(Pk) [~~ tpe~od]
As this demonstrates, the duty cycle tltperiod can be altered to compensate for input
voltage changes or load variations.
The duty cycle t/tperiod can be altered a number of different ways.
ton (inductor charge time)
tperiod

Total time (ton +toff+tI) where tI is the time from toff until the start
of the next charge cycle.

Knowing tperiod then:

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1
f=-tperiod

4-29

IL'
---.

~!Tlc ~
-=

/

1X

0.2 0.4 0.6 0.8
t

tperiod
(a)

CHANGES IN THE LOAD CURRENT WITH DUTY CYCLE

2
I-

Z

LU

a:
a:
=>
u
a:
0

0
-IL

l-

t)


I-

::J

0..

I-

::J

o

ISC
OUTPUT CURRENT

Figure 32. Constant-Current Limiting
This normally requires the use of a pass transistor with power handling capabilities much
greater than those required for normal operation i.e.:
VI

=

20 V

NOMINAL PD
For ISC

=

=

Vo

=

12 V

10

(20 V-12 V)xO.7 A

=

700 rnA

= 5.6 W

I A(150% lOUT):

SHORT-CIRCUIT PD

=

20 V x 1 A

=

20 W

This requirement may be reduced by the application of fold-back current limiting.

Fold-Back Current Limiting
Fold-back current limiting is used primarily for high-current applications where the
normal operating requirements of the regulator dictate the use of an external power
transistor. The performance characteristics of a fold-back current limiting regulator are
illustrated in Figure 33. The principle of fold-back current limiting provides limiting at
a predetermined current (II(). At this predetermined current, feedback reduces the load
current as the load continues to increase (RL decreasing) and causes the output voltage
to decay.
The fold-back current-limiting circuit of Figure 34, behaves in a manner similar
to the constant-current limit circuit illustrated in Figure 31. In Figure 34, the potential
developed across the current limit sense resistor (RCO must not only develop the baseemitter voltage required to turn on Q 1, but it must develop sufficient potential to overcome
the voltage across resistor RI.
VBE(Ql)
.
.. IK

= RCUL
=

II
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- VO+RCULXRI
Rl+R2

VBE(Ql) (Rl +R2)+VORI
RCLR2

4-39

w VO~-------------------------~

C!J

~
o
>

..J
~

:l
Q.
t:l

o

ISC
LOAD CURRENT

Figure 33. Fold-Back Current Limiting
As the load current requirement increases above IK, the output voltage (Vo) decays.
The decreasing output voltage results in a proportional decrease in voltage across Rl. Thus,
less current is required through RcL to develop sufficient potential to maintain the forwardbiased condition ofQ1. This can be seen in the above expression for IK. As Vo decreases,
IK decreases. Under short-circuit conditions, (VO = 0) IK becomes:
ISC

= IK @

(VO

= 0) = VBE(Ql)
RCL

[1 + Rl]

R2

The approach illustrated in Figure 34 allows a more efficient design because the
collector current of the pass transistor is less during short-circuit conditions than it is during
normal operation. This means that during short-circuit conditions, when the voltage across
the pass transistor is maximum, the collector-emitter current is reduced. As illustrated
in Figure 35, fold-back current limiting fits closer to the typical performance characteristics
of the transistor, thus allowing a better design match of the pass transistor to the regulator.
EXTERNAL PASS
TRANSISTOR -..

ILOAD

---.

~'-JVo,"""""'~
RCL

REGULATOR

Vo

R2
CURRENT-LIMIT
"'::" SENSE ELEMENT

Figure 34. Fold-Back Current Limit Configuration
4-40

w

~

FOLD-BACK CURRENT
LIMITING

I..J

o
>
a:

VI

w

T.--

------

I-

1-(;

~Q
LI;I w
a: u

0>

CONSTANT-CURRENT
LIMITING

+- TYPICAL TRANSISTOR

t;

w

SOA CURVE

..J
..J

o

U

ISC
LOAD CURRENT/COLLECTOR CURRENT Q3

Figure 35. Fold-Back Current Limit Safe Operating Area

Three-Terminal Regulators
Three-terminal IC regulators have been especially useful to the designer of small,
regulated power supplies or on-card regulators. Three-terminal regulators are popular
because they are small and require a minimum number of external components.

Stabilization
Mounting and using three-terminal regulators usually presents no problem, however,
there are several precautions that should be observed. Positive regulators, in general, use
n-p-n emitter follower output stages whereas negative regulators use n-p-n common-emitter
stages with the load connected to the collector. The emitter follower output stage
configuration is not used in negative regulators because monolithic p-n-p series-pass
transistors are more difficult to make. Due to their output stage configuration, positive
regulators are more stable than negative regulators. Therefore, the practice of bypassing
positive regulators may be omitted in some applications. It is good practice, however,
to use bypass capacitors at all times.

•

For a positive regulator, a 0.33-J'F bypass capacitor should be used on the input
terminals. While not necessary for stability, an output capacitor of 0.1 J'F may be used
to improve the transient response of the regulator. These capacitors should be on or as
near as possible to the regulator terminals. See Figure 36.

CJ

en

c
o

"';::;
CO

...

CI)

"C

.C;;
C

o

cC)
"C;;
CI)

C

When using a negative regulator, bypass capacitors are a must on both the input
and output. Recommended values are 2 J'F on the input and 1 J'F on the output. It is
considered good practice to include a 0 .1-J'F capacitor on the output to improve the transient
response (Figure 37). These capacitors may be mylar, ceramic, or tantalum, provided
that they have good high frequency characteristics.

4-41

POSITIVE
REG

t-.--+Vo
0.1/oL F

Figure 36. Positive Regulator

NEGATIVE
REG

t-...-~....--Vo
0.1/oL F

Figure 37. Negative Regulator

Fixed Dual Regulators

cCD
til

cE'
::s

n
o
::s

til

c:
CD

...0'
~

I»

::s
til

4-42

When building a dual power supply with both a positive and a negative regulator,
extra precautions should be taken. If there is a common load between the two supplies,
latch-up may occur. Latch-up occurs because a three-terminal regulator does not tolerate
a reverse voltage of more than one-diode drop. To prevent this latch-up problem, it is
good design practice to place reversed-biased diodes across each output of a dual supply.
While the diodes should not be necessary if the dual regulator outputs are referenced to
ground, latch-up may occur at the instant power is turned on, especially if the input voltage
to one regulator rises faster than the other. This latch-up condition usually affects the positive
regulator rather than the negative regulator. These diodes prevent reverse voltage to the
regulator and prevent parasitic action from taking place when the power is turned on.
The diodes should have a current rating of at least half the output current. A recommended
circuit for a dual 15-V regulated supply is illustrated in Figure 38.
In Figure 38, IN4001 diodes are placed directly across the regulators, input to output.
When a capacitor is connected to the regulator output, if the input is shorted to ground,
the only path for discharging the capacitor normally is back through the regulator. This
could be (and usually is) destructive to the regulator. The diodes across the regulator divert
any discharge current, thus protecting the regulator.

1N4001

t-.....~.--....- +15 Vo
+20 V ~......_-t
INPUT
'---..,..---'
1N4001

1N4001
-20 V ~......_-t
t-~H"""",-~"",--1S Vo
INPUT
L..._ _ _......

1N4001.

Figure 38. Regulated Dual Supply

Series Adjustable Regulator
Figure 39 illustrates a typical circuit for an LM317 adjustable positive regulator with
the output adjustable from 1.2 V to 17 V and up to 1.S A of current. (A typical input
supply uses a 2S.2-V transformer and a full-wave bridge rectifier.)
Stabilization, as described earlier for fixed three-terminal regulators, is usually not
required. Although the LM317 is stable with no output capacitors, like any feedback circuit,
certain values of external capacitance can cause excessive ringing. This effect occurs with
values between SOO pF and SOOO pF. Using a lO-p,F aluminum electrolytic on the output
swamps this effect and ensures stability.

en
C

o
-;::
~

01

CD

"0
'Ci)
1N4002
INr----....,OUT
+ --41~""'"
LM317
F~t-...- - - -...----4.....+
+
10 j.lF
INPUT
AOJ

35 V _ C1

1_

2000 j.lF

10j.l F

27...,0.n~~R_1_1_N_4_00_2---'

....+_ _ _

J_

C2

OO-F-

C

o

OUTPUT
1.2 V TO 17 V
AT 1.SA

o

c

C)

'Ci)
CD

C

"::" R2 Skn

Figure 39. Positive Adjustable Series Regulator

4-43

C 1 is the power supply ftlter capacitor following the rectifier section and should
be connected close to the regulator input for maximum stability. If the input were to be
shorted, 01 would divert the discharge current around the regulator, protecting it. Also,
with both 01 and 02 in the circuit, when the input is shorted, C2 is discharged through
both diodes. In general, a diode should be used in the position occupied by 01 on all
positive regulators to prevent reverse biasing. This becomes more important at higher output
voltages since the energy stored in the capacitors is larger. Bypassing the adjustment terminal
(C2) improves ripple rejection. Output capacitor C3 is added to improve the transient
response of the regulator.
In both the negative (LM337) and the positive (LM317) series adjustable regulators,
there is an internal diode from the input to the output. If the total output capacitance is
less than 25 p.F, 01 may be omitted.

Layout Guidelines
As implied in the previous sections, component layout and orientation plays an
important, but often overlooked, role in the overall performance of the regulator. The
importance of this role depends upon such things as power level, the type of regulator,
the overall regulator circuit complexity, and the environment in which the regulator
operates. The general layout rules, as well as remote voltage sensing, and component layout
guidelines are discussed in the following text.

Layout Design Factors
Most integrated circuit regulators use wide-band transistors to optimize their response.
These regulators must be compensated to ensure stable closed-loop operation. This
compensation can be counteracted by a layout which has excess external stray capacitance
and line inductance. For this reason, circuit lead lengths should be held to a minimum.
Lead lengths associated with external compensation or pass transistor elements are of
primary concern. These components, especially, should be located as close as possible
to the regulator control circuit. In addition to affecting a regulator's susceptibility to spurious
oscillation, the layout of the regulator also affects its accuracy and performance.

Input Ground Loop
Improper placement of the input capacitor can induce unwanted ripple on the output
voltage. Care should be taken to ensure that currents in the input circuit do not flow in
the ground line that is in common with the load return. This would cause an error voltage
resulting from the peak currents of the ftlter capacitor flowing through the line resistance
of the load return. See Figure 40 for an illustration of this effect.

4·44

REGULATOR
RECTIFIER

RCL

~--------~~IN

OUT~~~~~
SENSE~----~

G

(a) TYPICAL LAYOUT

RECTIFIER

R3'

R"

tI)

C

(b) LAYOUT ERROR CONTRIBUTIONS

Figure 400 Circuit Layout Showing Error Contributions

o

..

o~

m
CD

"0

Output Ground Loop

Similar in nature to the problem discussed on the input, excessive lead length in
the ground return line of the output results in additional error. Because the load current
flows in the ground line, an error equivalent to the load current multiplied by the line
resistance (R3') will be introduced in the output voltage.

°iii

c

o

()

cC)
"iii
CD
C

4-45

Remote Voltage Sense
The voltage regulator should be located as close as possible to the load. This is true
especially if the output voltage sense circuitry is internal to the regulator'S control device.
Excessive lead length will result in an error voltage developed across the line resistance
(R4').

Vo
ERROR

VO(reg) - (R2'+ R3'+ R4') IL +R2'I reg
IL(R3' + R4') - I reg R2'

If the voltage sense is available externally, the effect of the line resistance can be
minimized. By referencing the low current external voltage sense input to the load, losses
in the output line are compensated. Since the current in the sense line is very small, error
introduced by its line resistance is negligible (Figure 41).
REGULATOR
HIGH-CURRENT PATH.
RCL

RECTIFIER
~--------~~IN

OUT~--~VVr--------O

SENSE~--------~------~

G

LOW-CURRENT
LOOP

cCD

ce·VI::::I

Figure 41. Proper Regulator Layout

(")

o

::::I
VI

c.:CD

......

II)

o·::::I

Input Supply Design
When the power source is an ac voltage, the transformer, rectifier, and input filter
design are as important as the regulator design itself for optimum system performances .
This section presents input supply and filter design information for designing a basic
capacitor input supply.

VI

Transformer/Rectifier Configuration
The input supply consists ofthree basic sections: (1) input transformer, (2) rectifier,
and (3) filter as illustrated in Figure 42. The first two sections, the transformer and the
rectifier, are partially dependent upon each other because the structure of one depends
upon that of the other. The most common transformer configurations and their associated
rectifier circuits are illustrated in Figure 43.
4-46

I

~ ...-

AC
INPUT

TRANSFORMER

I

I
I
I

I
I

I
RECTIFIER I

.1..

;r
FILTER

DC

I OUTPUT
I
I
I

I
I

Figure 42. Input Supply

TRANSFORMER
SECONDARY ---....

(8)

LOAD

SINGLE-PHASE HALF-WAVE

TRANSFORMER
SECONDARY
""(CENTER TAPPED)

•..
fI)

...oca
C

LOAD

Q)

"C

·0
C

(b) SINGLE-PHASE CENTER-TAPPED FULL-WAVE

o

o

c
en
·0

TRANSFORMER
SECONDARY ---...

Q)

C
LOAD

(c)

SINGLE-PHASE FULL-WAVE BRIDGE

Figure 43. Input Supply Transformer/Rectifier Configurations
4-47

The particular configuration used depends upon the application. The half-wave circuit
[Figure 43(a)] is used in low-current applications. This is because the single rectifier diode
experiences the total load current and its conversion efficiency is less than 50%. The fullwave configurations [Figure 43(b) and 43(c)] are used for higher current application. The
characteristic output voltage waveforms of these configurations are illustrated in Figure 44.
INPUT SIGNAL

HALF-WAVE

1\

FULL-WAVE

, IV\

Figure 44. Rectifier Output-Voltage Waveforms
Before the input supply and its associated filter can be designed, the voltage, current,
and ripple requirements of its load must be fully defined. The load, as far as the input
supply is concerned, is the regulator circuit. Therefore, the input requirements of the
regulator itself become the governing conditions. Because the input requirements of the
regulator control circuit govern the input supply and filter design, it is easiest to work
backwards from the load to the transformer primary.

Capacitor Input Filter Design

•

The most practical approach to a capacitor-input filter design remains the graphical
approach presented by D.H. Schadel in 1943. The curves illustrated in Figures 45 through
48 contain all of the design information required for full-wave and half-wave rectifier
circuits.
Figures 45 and 46 illustrate the ratio of the dc-output voltage developed (V C) to
the applied peak input voltage (V (PK) , as a function of ",CRL for half-wave and fullwave rectified signals, respectively. For a full-wave rectified application, the voltage
reduction is less than 10% for ",CRL > 10 and Rs/RL < 0.5%. As illustrated, the voltage
reduction decreases as ",CRL increases or the RS/RL ratio decreases. Minimizing the
reduction rate, contrary to initial impressions, may prove to be detrimental to the optimum
circuit design. Further reduction requires a reduction in the series to load resistance ratio
(RS/RL) for anr given ",CRL. This will result in a higher peak-to-average current ratio

IO.H. Schade, "Analysis of Rectifier Operation", Proc. IRE., VOL. 31, 343, 1943.

4-48

100

I
.... ,

I
RS

f-

I

I

I

I

T

vIr ~ vf

f-

0.05

~

~v ",;'

I

i

-n
90

I

RL

A~

f-

0.5

I---

2

I/'; /

80

/J V V

A~ 7

70

~

4

I-"'

6

I---

&vv /'"...-

8

I--'"

rh v
I........

60

Vc

-- %

10
12.5

p
J~v

50

V(PK)

~

40

~

~
c:::v

E:-

---

~

15

20

...-

25
30

~~

35

~~ v

30

I-I--

~~~
=::::
~V
.J'

40
50

100"

60
70

--

80
90
100

r~ V
I .....
~V

t:::. I..--'

20

RS
-%
RL

•.
I/)

c

o

'';:;

as

CI)

'C
'u)
C

10

o
CJ

c

en

o
0.1

0.2

0.4

0.7 1

2

4

7

10

20

40

70 100

200

400 700 1000

wCRL - C IN FARADS. RL IN OHMS, w = 2 "f, f = LINE FREQUENCY

'u)

CI)

c

Figure 45. Relation of Applied Alternating Peak Voltage to Direct Output
Voltage in Half-Wave Capacitor-Input Circuits
(From O.H. Schade, Proc. IRE, Vol. 31, p. 343, 1943)

4-49

FULL·WAVE
RS

100

]

..

t

J

, "hfi
~

I

CT

RL

~

~~

FULL·WAVE BRIDGE

90

RS

l

80

~ /"

i"~ "
,/

l~ V ,.,...
J. ~ ~ ,.,...,.,...
~ "".,...

",

",

J"

70

~

:;;::; ~~ V/

~%
V(PKI

60

~~

--

/ V

~~

I- :::::.---I,...-

i--

c

:::J

a:CD

..o·
;

:::J
(I)

4

6
8
1o
12.5
15

"

.-

30

.........

35
40

,...

60

50

70
80

90
100

30

0.1

0.2

0.4

0.7. 1

2
4
7 10
20
40
70 100
200
400
wCRL - C IN FARADS, RL IN OHMS, W = 2 nf, f = LINE FREQUENCY

700 1000

Figure 46. Relation of Applied Alternating Peak Voltage to Direct Output
Voltage in Full-Wave Capacitor-Input Circuits
(From O.H. Schade, Proc. IRE, Vol. 31, p. 344, 1943)
through the rectifier diodes (see Figure 47). In addition, and probably of more concern,
this increases the surge current experienced by the rectifier diodes during tum-on of the
supply. It is important to realize that the surge current is limited only by the series resistance
RS·
ISURGE

4-50

2

-~

(I)

(I)

~

0.5

....-

i--

CD

o
o

-

-'

40

:::J

----

- - --- ------f--"

50

cC·

:::::--

O.OS
0.1

VSEC(PK)
RS

iii 10
Q

o

7

C

0.02

V 0.05

-

a:

;'

~ 4

>

.e

1

:!

t:: 1052

~ 2
iii
:;;
a:

~

0.1
0.2 ..J
0.5 a:

if

....

30
~ 100

0.1

0.2

0.4

0.7

1

4

2

7

10

20

40

70 100

200

400

700 1000

100
70
_

40

w

C

0.02
0.05
0.1
0.2

~~

o
C

a: 20

Ld ~

w

~

~ I--

I---

~

> 10

:!

0.5
1

2 a:
5 ....
10
30
100

IL

:::

7

~

4

~


·S

C'

w

I

a:
en
w
00

0.1

0.2

O. 3

0.4

0.5

0.6

0.7

0.8

.1IL -Load Current Range-A
(b) ESR vs WAD CURRENT

Figure 49. Typical Response Curves for the TL750MXX Series

4-54

Thermal Considerations in Design of Power Supplies
Introduction
Power supply circuit designers place emphasis on suppressing transients, improving
regulation, and increasing efficiency, yet concentrate minimum effort toward thermal
considerations and packaging of the power supply. Serious efforts must be given to thermal
design and packaging to minimize power supply failures in the field. If sufficient attention
is given to the important parameters supplied by the semiconductor manufacturers (e.g.,
maximum junction temperature, junction-to-case, and junction-to-ambient thermal
resistance), proper heat removal can be achieved. Thermal resistance is the temperature
difference between two points divided by the power dissipation, normally stated in °C/W.
The reference temperature can be the ambient temperature or the temperature of a heat
sink that the integrated circuit (IC) package is attached to.
Heat can be transferred from the transistor or integrated circuit package by three
methods; conduction, convection, and radiation.
ConductiC!,n is transmission of energy by a medium not involving movement of the
medium itself. This method is predominate in junction to the case or from the case to
a heat sink heat transfer from the semiconductor. Length, cross-section, and temperature
differential of the medium are key parameters that determine conduction.
Convection is transmission of energy or mass by a medium involving movement
of the medium itself. This method predominates in the transfer of heat from the case to
ambient or a heat sink to ambient. Surface conditions, convecting fluids, velocity, and
temperature difference are dominant factors in convection.
Radiation is the emission and propagation of waves transmitting energy through space
or some medium. This method is important in heat transfer from the cooling-fin surface
of a heat sink. Thermal emissivity, surface-area, and temperature difference between
radiating and adjacent mediums are key factors that determine radiation.

Basic Thermal Circuit and Symbols
Figure 50 illustrates the various heat flow paths, temperatures, and thermal resistances
of a steady-state thermal model using a KC package with formed leads. A popular concept
is to display this thermal model as a network of series resistors as shown on Figure 51,
comparing the thermal circuit analogy to an electric circuit. Extending this Ohm's-law
concept of this thermal circuit, temperature is analogus to voltage and thermal resistance
to ohmic resistance. Inspection of Figure 51 will provide an expression for:

= TA + Po(RoJC + ROCS + ROSA)
or TJ = TA + Po(RoJN for a regulator without external heat sink
TJ

II
U)

r:::

o

'.j:i

...

CO
G)

"C

'iii
r:::
o
CJ
r:::
en
'iii
G)

o

(1)

4-55

where

= junction temperature in °c
= ambient air temperature in °c
= thermal resistance, junction-to-case in °C/W
= thermal resistance, case-to-heat sink °CIW
= thermal resistance, heat sink-to-ambient in °C/W
= thermal reaistance, junction to ambient °C/W
Po = power dissipated by semiconductor device in W

TJ
TA
RoJC
Rocs
RosA
RoJA

PLASTIC FLANGE-MOUNTED CASE

T

R8JA

1

ATMOSPHERE X
OR AMBIENT

Figure 50. Semiconductor Thermal Model

c
CD
tI)

cO'
:::I

n
o
:::I

tI)

c:
CD

...D;c)'
:::I

tI)

4-56

The junction-to-ambient thermal resistance RoJA can be expressed as a sum of thermal
resistances listed below:
RoJA

= ROJC + ROCS +

RoSA

(2)

Equation 2 is applicable only when an external heat sink is used. If only a mounting
(internal) heat sink is used, or the device does not have a heat sink, the RoJA is equal
to the RoJA specified on the product data sheet. ROJC normally will be given on the data
sheet also, and the junction-to-case thermal resistance is a function of the material, and
size of the package, die area and thickness, and integrity of the die bond to the case, lead
frame, or chip carrier. ROCS depends on the package, heat-sink-interface (mounting of
the regulator to the heat sink) area, and integrity of the contact surface. Typical values
for Rocs for different packages are shown in Table 1.

Po (POWER-W)
TJ. JUNCTION TEMPERATURE
TJ > TC

T C. CASE TEMPERATURE
TC > TS

TS. HEAT-SINK TEMPERATURE
TS

> TA

T A. AMBIENT TEMPERATURE
(REFERENCE TEMPERATURE)

Figure 51. Basic Semiconductor Heat Sink Steady State Thermal Circuit
Table I"
PACKAGE
TO-3
KC

(TO-220)

Rocs for Different Types of Packages and Mounting Conditions
METAL TO

METAL-TO-METAL WITH

CONTACT WITH MICA WASHER

METAL

THERMAL COMPOUND

AND THERMAL COMPOUNDt

0.52 DC/W

0.14DC/W

0.36 DC/W

1.1 DC/W

1.0DC/W

1.7DC/W

tTypical values extracted from heat-sink manufacturer's curves

II

...
II)

C

o

"

ca

Q)

"C

"in
c
o

(,)

The RoSA found on the heat sink data sheets depends on the attributes of the heat
sink and the ambient conditions. Convection and radiation are heat flow methods affecting
the heat sink to ambient thermal resistance.

c

C)

"in
Q)
C

4-57

Typically, the ambient temperature (TA), maximum junction temperature (TJ), power
dissipation (PD), thermal resistance fromjunction-to-case (RoJc), and thermal resistance
from junction to ambient air (ROJA) are known. To ensure safe operations of any
semiconductor, the device junction temperature must be maintained below the maximum
value given on the product data sheet. As with any semiconductor component, these devices
have thermal and electrical limitations that must be adhered to if desired performance and
service time are to be achieved. In addition, improved reliability can be obtained by selecting
conservative operating procedures and thermal ranges. Normally, the electrical and thermal
characteristics are interrelated with the actual operating ranges that are heavily dependent
on the component application.

Thermal Design Examples
The following examples are given to illustrate the design procedure in:
I. Ascertaining the maximum allowable power dissipation of a semiconductor
device
2. Determining the maximumjunction-to-ambient air temperature (TAmax) using
a mounting (internal) heat sink, or regulator without internal heat sink
3. Selecting an external heat sink by calculating the heat sink-to-ambient thermal
resistance (RosA).
To ascertain the maximum allowable power dissipation of a semiconductor device,
use equation 3:
P

cCD

_ TJmax - TA
D ROJA

(3)

tn

cO'
::s
(')

o

::s
tn

a:CD

..

m
"'
0'
::s
tn

where
TJmax = 150°C (design limit)
TA = 75°C
RoJA = 1Iderating value = 118.2 mW/oC (DW package)
TJmax = TA + Po(RoJC + Rocs + RosA)

121.95°C/W

To ascertain the maximum TA for an uA78MI2C regulator with an internal heat
sink, use equation 4:
TJ
TA
TA
TA

4-58

=

= TA + Po(ROJA)
= TJ - Po(ROJA)
= 125 - (0.8 X 62.5)
= 75°C

(4)

where
PD
TJ

= 0.8 W
= 125°C

RoJA

= 1Iderating factor = 110.016 = 62.5°C/W
Derating factor of KC (TO-220) package is 16 mW/oC (from uA78M12C data
sheet)

To ascertain the heat sink-to-ambient thermal resistance (R8SA) for selection of
external heat sink using the uA7915C regulator, the heat sink should be mounted metalto-metal using thermal compound.

RosA =

TJ - TA
PD

-

(5)

RoJC - Rocs

RosA = 125 - 75 - 4 - 1 = 11.7 0 C/W
3

where
PD =3W
TJ = 125°C
TA = 75°C
RoJC = 4°C/W (from the uA7915C data sheet)
Rocs = I°C/W from Table 1 (KC or TO-220 case).
TJ - TA
R8JA =
= RoJC + Rocs + RosA
PD
A Thermalloy 7019 or Staver V3-5 heat sink will meet the desired requirements
(see Table 3).
Table 2" Available Heat Sinks for TO-3 Packages
STAVER

°C/W
3 to 5

V3-5-2

5 to 8

V3-3-2

8 to 13

V1-3,V1-5,V3-3, V3-5, V3-7-96

..

"+:0

ca
CD

"C

";;

MANUFACTURER*

ROSA RANGEt

fI)

C

o

THERMALLOY

6004.6053.6054.6214.6216
6002.6003.6015,6016,
6052,6060,6061,6213
6001,6013,6014,6051

C

o

o

cC)
";;
CD

C

t All values are typical as determined from characteristic curves received from manufacturers.
:l:This table is a representative of two heat sink manufacturers, many others are available.

4-59

Table 3. Available Heat Sinks for KC (TO-220) Packages
MANUFACTURER:!:

ROSA RANGEt
°C/W
3 to 5
5 to 8
8 to 13

STAVER
V3-5-2
V3-3-2
V3-3, V3-5

THERMALLOY

6072/6071
6072,7021,7025
6021,6030,6032,7019,7020

t All values are typical as determined from characteristic curves received from manufacturers.
*This table is a representative of two heat sink manufacturers, many others are available.

General Suggestions for Efficient Thermal Management
Suggestions are as follows:
1. Place regulator components away from heat-dissipating components and mount
hardware in an area that provides a good heat-dissipation path for the regulator.
2. For applications requiring electrical insulation of the heat-sink from the
regulator use a thin (0.003 inch) mica washer. A thermal lubricant must be
placed on both sides of the washer.
3 . If a heat sink with fins is used with the regulator, align the fins in a vertical
plane for a more efficient transfer of heat.

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4. Select heat sink with a mounting surface that has a finish and flatness
comparable to the regulator package. Use thermal compounds to minimize
voids, scratches, and imperfections between the mating surfaces. Use of
thermal compounds with an insulating washer is more significant than with
a metal-to-metal contact.
S . Attach regulator heat sink to the regulator before soldering and mounting on
the PC board. Maximum lead temperatures are 260 °C for ten seconds with
plastic packages or 300 °C for sixty seconds for cermanic packages at a distance
of 1I16th inches from case.

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Conclusion

...

Thermal considerations in the design of power supplies are straight-forward, and
with emphasis on heat reduction and conservative operating techniques; more efficient
and reliable designs will be realized. The design parameters are normally under the control
of the circuit designer and, with compromises, the variables can be controlled to achieve
a product that will experience fewer failures in the field. On the other hand, if the thermal
design considerations are overlooked or minimized, many of the power supply failures
in the field may result from an inadequate thermal design approach.

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4-60

Switching Power Supply Design

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TEXAS
INSTRUMENTS

4-61

IMPORTANT NOTICE
Texas Instruments (Tn reserves the right to make changes to or
to discontinue any semiconductor product or service identified
in this publication without notice. TI advises its customers to
obtain the latest version of the relevant information to verify,
before placing orders, that the information being relied upon is
current.
TI warrants performance of its semiconductor products to current
specifications in accordance with TI's standard warranty. Testing
and other quality control techniques are utilized to the extent TI
deems necessary to support this warranty. Unless mandated by
government requirements, specific testing of all parameters of
each device is not necessarily performed.

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4-62

TI assumes no liability for TI applications assistance, customer
product design, software performance, or infringement of patents
or services described herein. Nor does TI warrant or represent that
any license, either express or implied, is granted under any patent
right, copyright, mask work right, or other intellectual property
right of TI covering or relating to any combination, machine, or
process in which such semiconductor products or services might
be or are used .

Copyright

© 1988, Texas Instruments Incorporated

Contents
Title

Page

Introduction ............................................-......... .

4-69

Basic Operation of Switching Regulators ............................. .

4-69

Advantages of a Switching Regulator .................................. .
Disadvantages of a Switching Regulator ................................ .
Basic Switching Regulator Architecture ................................ .
The Step-Down Regulator ...................................... .
The Step-Up Regulator ........................................ .
The Inverting Regulator ........................................ .
Forward Converters .................................................•
Push-Pull Converter ........................................... .
Half-Bridge Converter ......................................... .
Full-Bridge Converter ......................................... .

4-70
4-71
4-72
4-72
4-72
4-73
4-74
4-75
4-75
4-76

TL493 Floppy Disk Power Supply ................................... .

4-77

Transformer Construction ........................................... .

4-78

TL594 12-V to 5-V Step-Down Regulator ............................. .

4-79

Specifications ..................................................... .
The TL594 Control Circuit .......................................... .
Reference Regulator ........................................... .
Oscillator ................................................... .
Dead-Time and PWM Comparators .............................. .
Error Amplifiers .............................................. .
Output Logic Control .......................................... .
The Output Driver Stages ...................................... .
Soft Start ........................................................ .
Overvoltage Protection ............................................. .

4-81
4-81
4-83
4-83
4-83
4-84
4-84
4-85
4-86
4-86

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4-63

Contents (Continued)
Designing a Power Supply (5-V/I0-A Output) .......................... 4-87
Design Objective . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..
Input Power Source .................................................
Control Circuits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..
Oscillator ....................................................
Error Amplifier . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..
Current Limit Amplifier . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..
Soft Start and Dead Time .......................................
Inductor Calculations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..
Output Capacitance Calculations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..
Transistor Power Switch Calculations ...................................

4-87
4-87
4-88
4-88
4-89
4-89
4-90
4-91
4-92
4-93

TL497A Switching Voltage Regulator ................................. 4-94
Step-Down Switching Regulator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..
Step-Up Switching Regulator .........................................
Inverting Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..
Design Considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..

4-96
4-98
4-98
4-100

A Step-Down Switching Regulator Design Exercise with TL497A ......... 4-102
Design and Operation of an Inverting Regulator Configuration ........... 4-105
Adjustable Shunt Regulator TL430-TL431 ............................ 4-106
Shunt Regulator Applications (Crowbar) .............................. 4-110

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Controlling Vo of a Fixed Output Voltage Regulator .................... 4-111

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Current Limiter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 4-111

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Voltmeter Scaler . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 4-112

en

Voltage-Regulated, Current-Limited Battery Charger
for Lead-Acid Batteries .......................................... 4-113

...Dlcr

Battery Charter Design ..............................................
Rectifier Section . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..
Voltage Regulator Section .......................................
Current Limiter Section .........................................
Series Pass Element ............................................
Design Calculations ............. ; . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..
Power Dissipation and Heat Sinking ...............................

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4-64

4-113
4-114
4-115
4-116
4-117
4-118
4-119

Contents (Concluded)
Voltage Supply Supervisor Devices ................................... 4-120

GeneralOperation ..................................................
TL77XXA Series Supervisor Chips ....................................
Operation During a Voltage Drop .................................
TL77XXA Series Applications. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..

4-120
4-121
4-123
4-124

uA723 Precision Voltage Regulator ................................... 4-127

Typical Applications ................................................ 4-129
General-Purpose Power Supply . ..................................... 4-131
8-A Regulated Power Supply for Operating Mobile Equipment ........... 4-133

± 15-V at I-A Regulated Power Supplies .............................. 4-134
Positive Supply .................................................... 4-134
Negative Supply. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 4-135
Overvoltage Sensing Circuits ........................................ 4-137

The Crowbar Technique. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 4-137
Activation Indication Output . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 4-140
Remote Activation Input ............................................. 4-140

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4-66

List of Illustrations
Figure
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36

Title

Basic Switching Regulator Block Diagram .......................... .
Step-Down or "Buck" Switching Regulator Circuit ................... .
Step-Up or "Boost" Switching Regulator Circuit ..................... .
Inverting or "Flyback" Switching Regulator Circuit .................. .
Forward Converter Switching Regulator ............................ .
Basic Push-Pull Converter Circuit ................................. .
Half-Bridge Converter Circuit .................................... .
full-Bridge Converter Circuit .................................... .
TU93 Floppy Disk Power Supply ................................. .
Transformer Winding Layout ..................................... .
TL594 12-V to 5-V Step-Down Regulator .......................... .
12-V to 5-V Series Switching Regulator Waveforms .................. .
TL594 Block Diagram .......................................... .
Output Pulses vs Sawtooth Control Voltage ......................... .
Deadtime Comparator Operation .................................. .
Amplifier Performance Curves ................................... .
Soft-Start Circuit .............................................. .
Overvoltage Protection Circuit .................................... .
Input Power Source ............................................ .
Switching and Control Section ................................... .
Error Amplifier Section ......................................... .
Current Limit Circuit ........................................... .
Soft-Start Circuit .............................................. .
Switching Circuit .............................................. .
Power Switch Section ........................................... .
TL497 A Block Diagram ........................................ .
Basic Power Supply Configurations ................................ .
Step-Down Switching Regulator .................................. .
Positive Regulator, Step-Down Configurations ....................... .
Step-Up Switching Regulator .................................... .
Positive Regulator, Step-Up Configurations ......................... .
Basic Inverting Regulator Circuit ................................. .
Inverting Applications .......................................... .
Basic Step-Down Regulator ...................................... .
15-V to 5-V Step-Down Regulator ................................ .
Step-Down Regulator ........................................... .

Page
4-70
4-72
4-73
4-73
4-75
4-75
4-76
4-76
4-77
4-78
4-80
4-80
4-82
4-82
4-84
4-85
4-86
4-86
4-87
4-88
4-89
4-90
4-91
4-92
4-93
4-94
4-95
4-96
4-97
4-98
4-99
4-100
4-101
4-102
4-104
4-104

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List of Illustrations (Continued)

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37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63

5-V to 15-V Switching Regulator ..................................
+ 5-V to - 5-V Switching Regulator ...............................
TL430/TL431 Adjustable Shunt Regulators ..........................
Basic Operating Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..
Reference Input Voltage vs Ambient Temperature .....................
Basic Operational Circuit. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..
Series Regulator Circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..
Shunt Regulator in Crowbar Circuit ................................
Fixed Output Shunt Regulator ............ . . . . . . . . . . . . . . . . . . . . . . . ..
Current Limiter ................................................
Voltmeter Scaler ................................................
Current-Limited and Voltage-Regulated Battery Charger . . . . . . . . . . . . . . ..
Full-Wave Rectifier Section of Circuit ...............................
Voltage Regulator Section of Circuit ................................
Current Limiter Section of Circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..
Series Pass Element .............................................
Voltage and Current Path .........................................
Discrete Solution of a Voltage Supply Supervisor .....................
TL77XXA Series Function Block Diagram ...........................
Graph for Calculation of CT ......................................
Timing Diagram ................................................
TL7705A in 5-V Microcomputer Application .........................
TL7715A in TMSIXXXNLP Application ...........................
Voltage Supervision of a Multiple Power Supply ......................
Delayed Triggering ..............................................
Circuit Diagram for Memory Protection .............................
uA723 Functional Block Diagram ..................................
64 uA 723 Schematic ...............................................
65 Typical Applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
66 General-Purpose Power Supply ....................................
67 8-A Regulated Power Supply ......................................
68 + 15-V at I-A Regulated Power Supply .............................
69 -15-Vat I-A Regulated Power Supply .............................
70 MC3423 Overvoltage Crowbar Sensing Circuit Block Diagram ..........
71 Typical Crowbar Circuit ..........................................
72 Overvoltage Protection Circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
73 Minimum RGvs Supply Voltage ...................................
74 Capacitance vs Minimum Overvoltage Duration . . . . . . . . . . . . . . . . . . . . . . .

4-104
4-106
4-107
4-107
4-109
4-109
4-110
4-110
4-111
4-112
4-112
4-114
4-115
4-115
4-116
4-117
4-119
4-121
4-122
4-123
4-123
4-125
4-125
4-126
4-127
4-127
4-128
4-128
4-130
4-132
4-134
4-134
4-135
4-137
4-138
4-138
4-139
4-139

Introduction
Modem electronic equipment usually requires one or more dc power sources. The
usual method of supplying dc power is a power supply which converts ac power to dc
power. The two types of dc power supplies in common use are classified by the type of
regulator employed; linear regulator and switching regulator.
Linear power supplies consist of a power transformer, rectifier and filter circuits, and
a linear regulator. Switching power supplies do not require line transformers; the ac input
is rectified and filtered, chopped by a high frequency transistor switch/transformer
combination, then rectified and filtered again.
Switching power supplies have been used for some time in the military and space
industry due to their smaller size and higher efficiency. In 1975, switching power supplies
were more cost effective than linear power supplies from approximately the 500-W power
level. Now the breakeven point is down to approximately 5 W.

Basic Operation of Switching Regulators
Figure 1 is a block diagram of a typical switching power supply which consists of
four basic circuits:
1. Input rectifier and filter
2. High frequency inverter
3. Output rectifier and filter
4. Control circuit.
The ac line voltage is applied to an input rectifier and filter circuit. The dc voltage
output from the rectifier and filter circuit is switched to a higher frequency (typically
25 kHz to 100 kHz) by the transistor switch in the high frequency inverter circuit. This
circuit contains either a high frequency transformer or inductor, depending on the output
voltage required.
Output from the high frequency inverter circuit is applied to the output rectifier and
filter circuit. The circuit is monitored and controlled by the control circuit which attempts
to keep the output at a constant level.

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Figure 1. Basic Switching Regulator Block Diagram

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The control circuit consists of an oscillator driving a pulse-width modulator, an error
amplifier, and a precision voltage reference. The error amplifier compares the input
reference voltage with a sample of the voltage from the output rectifier and filter circuit.
As the load increases, the output voltage drops. The error amplifier senses this drop and
causes the pulse-width modulator to remain on for a longer period of time, delivering
wider control pulses to the transistor switch.

.....

The width of the pulse determines how long the transistor switch allows current to
flow through the high frequency transformer and, ultimately, how much voltage is
available at the output. If the load decreases, narrower control pulses are delivered to the
switching transistor until the output voltage remains at a constant value .

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Advantages of a Switching Regulator

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The primary advantages of switching regulators are higher efficiency and smaller
size. Conventional linear series and shunt regulators operate in a continuous conduction
mode, dissipating relatively large amounts of power. The efficiency of linear regulators is
typically around 40% to 50%. When the input-to-output voltage differential is large, the
resultant efficiency is much lower than 40%.

4·70

Switching regulators have typical efficiencies of 60% to 90%; much higher than
either the linear series or shunt regulator. Switching regulators achieve their higher
efficiency as a result of three factors:
1. The power-transistor switch is always turned completely on or off, except
when it is switching between these two states, resulting in either low voltage
or low current during most of its operation.
2. Good regulation can be achieved over a wide range of input voltage.
3. High efficiency can be maintained over wide ranges in load current.
Switching regulators use the on-off duty cycle of the transistor switch to regulate the
output voltage and current. By using a frequency much higher than the line frequency
(typically 20 kHz to 500 kHz), the transformers, chokes, capacitors, and other filter
elements can be made smaller, lighter, and less costly. The smaller elements used in
switching regulators result in smaller power losses than the larger components used in
linear regulators. The highest cost elements of a switching power supply are the transistor
switches. The remaining costs, in descending order, are due to the magnetic components,
capacitors, and rectifiers.

Disadvantages of a Switching Regulator
Switching regulators can generate some electromagnetic and radio frequency
interference (EMI/RFI) noise due to high switching currents and short rise and fall times.
EMIIRFI noise, which is generated at higher frequencies (100 kHz to 500 kHz), is easily
filtered. In those applications where a large series impedance appears between the supply
and the regulator, the rapid changes in current also generate a certain amount of noise.
These problems may be overcome or significantly reduced by one or more of the
following steps:
1. Reducing the series impedance
2. Increasing the switching time
3. Filtering the input and output of the regulator.
Switching regulators with a fixed frequency are easier to filter than regulators with a
variable frequency because the noise is at only one frequency. Variable frequency
regulators with a fixed "on" time increase or decrease the switching frequency in
proportion to load changes, presenting a more difficult filtering problem.

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Basic Switching Regulator Architecture
There are three basic switching regulator configurations from which the majority of
present day circuits are derived:
1. Step-down or "buck" regulator
2. Step-up or "boost" regulator
3. Inverting or "flyback" regulator (which is a variation of the "boost"
regulator).

The Step-Down Regulator
Figure 2 illustrates the basic step-down or "buck" regulator. The output voltage of
this configuration is always less than the input voltage. In the buck circuit, a
semiconductor switch is placed in series with the dc input from the input rectifier/filter
circuit. The switch interrupts the dc input voltage providing a variable-width pulse to a
simple averaging LC filter. When the switch is closed, the dc input voltage is applied
across the filter and current flows through the inductor to the load. When the switch is
open, the energy stored in the field of the inductor maintains the current through the load.
In the buck circuit, peak-switching current is proportional to the load current. The output
voltage is equal to the input voltage times the duty cycle.
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4-72

The Step-Up Regulator
Another basic switching regulator configuration is the step-up or "boost" regulator
(Figure 3). In this type of circuit, the output voltage is always greater than the input
voltage. The boost circuit first stores energy in the inductor and then delivers this stored
energy along with the energy from the dc input voltage to the load. When the switch is
closed, current flows through the inductor and the switch, charging the inductor but
delivering no current to the load. When the switch is open, the voltage across the load
equals the dc input voltage plus the charge stored in the inductor. The inductor discharges,
delivering current to the load.

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Figure 3. Step-Up or "Boost" Switching Regulator Circuit
The peak switching current in the boost circuit is not related to the load current. The
power output of a boost regulator can be determined by the following equation:
POUT

LI2f

=2

where:
POUT = power output
L = inductance
I = peak current
f = operating frequency

The Inverting Regulator
The third switching regulator configuration is the inverting or "flyback" regulator.
This circuit is a variation of the step-up or "boost" circuit discussed previously. The
flyback circuit is illustrated in Figure 4. Flyback regulators, which evolved from "boost"
regulators, deliver only the energy stored by the inductor to the load. This type of circuit
can step the input voltage up or down. When the switch is closed, the inductor is charged,
but no current is delivered to the load because the diode is reverse biased. When the switch
is open, the blocking diode is forward biased and the energy stored in the inductor is
transferred through it to the load.

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4-73

The flyback circuit delivers a fixed amount of power to the load regardless of load
impedance. It is widely used in photo flash, capacitor-discharge ignition circuits, and
battery chargers.
To determine the output voltage of an electronic equipment supply, the load (RL)
must be known. If the load is known, the output voltage may be calculated using the
following equation:

Vo

=

y'PORL = I yLfr;L

where:

v0

= voltage output
Po = power out
RL = load resistance
I = inductor current
f = operating frequency

The inductor current is proportional to the "on time" (duty cycle) of the switch and
regulation is achieved by varying the duty cycle. However, the output also depends on the
load resistance (which was not true with the step-down circuit).
Transient response to abrupt changes in the load is difficult to analyze. Practical
solutions include limiting the minimum load and using the proper amount of filter
capacitance to give the regulator time to respond to this change. Flyback type circuits are
used at power levels of up to 100 W.

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Forward Converters

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The forward converter family, which includes the push-pull and half-bridge circuits,
evolved from the step-down or "buck" type of regulator. A typical forward converter
circuit is illustrated in Figure 5. When the transistor switch is turned on, the transformer
delivers power to the load through diode Dl and the LC filter. When the switch is turned
off, diode D2 is forward biased and maintains current to the load.

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Without the third winding and diode D3, the converter would lose efficiency at
higher frequencies. The function of this winding is to return energy stored in the
transformer to the line and reset the transformer core after each cycle of operation. This is
a popular low-power (up to about 200 W) converter and is almost immune to transformer
saturation problems.

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Figure 5. Forward Converter Switching Regulator

Push-Pull Converter
The push-pull converter is probably one of the oldest switching regulator type
circuits. It was first used in the 1930s with mechanical vibrators functioning as the switch.
When transistors became available, push-pull converters were used as free-running
oscillators in the primary of many automobile communication converters. Some
recreational vehicles still use this free-running type of oscillator converter in dc-to-dc
converters as well as in dc-to-ac inverters. A typical push-pull converter circuit is shown
in Figure 6.
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Figure 6. Basic Push-PuD Converter Circuit

Half-Bridge Converter
The most popular type of high-power converter is the half-bridge circuit illustrated
in Figure 7. The half-bridge converter has several advantages over the push-pull circuit.
First, the midpoint between the capacitors (point A) can be charged to VI/2. This allows
4-75

the use of transistors with lower breakdown voltage. Second, because the primary is driven
in both directions (push-pull), a full-wave rectifier and filter are used which allows the
transformer core to be more effectively utilized.
+--",--,

Vo

Figure 7. Half-Bridge Converter Circuit

Jibll-Bridge Converter

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In contrast to the half-bridge, the full-bridge (or H-Bridge) converter uses four
transistors as shown in Figure 8. In a full-bridge circuit, the diagonally opposite transistors
(QI/Q2 or Q3/Q4) are turned on during alternate half cycles. The highest voltage any
transistor is subjected to is VI, rather than 2 X VI as is the case in the push-pull converter
circuit. The full-bridge circuit offers increased reliability because less voltage and current
stress is placed on the transistors. The disadvantage of this circuit is the space required by
the four transistors and the cost of the two additional transistors.

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Figure 8. Full-Bridge Converter Circuit

4-76

TL493 Floppy Disk Power Supply
The TL493 incorporates, on a single monolithic chip, all the functions required for a
pulse-width modulation control circuit. The TL493 is similar to the TL594, from which it
was derived, except that the TL493 includes a current-limit amplifier instead of a seconderror amplifier.
The current-limit amplifier of the TL493 has an offset voltage of approximately
80 mV in series with the inverting input (pin 15). This makes it easier to design the
current-limit portion of the power supply and also requires fewer components. With
80 mV on the inverting input, it is only necessary to apply an 80-mV control voltage to the
noninverting input (pin 16). This is easily accomplished by taking the voltage across a
resistor in series with the load.
The floppy disk power supply schematic is shown in Figure 9. The power supply
uses a pair of TIP34 p-n-p transistors in a push-pull configuration. The oscillation
frequency is set at 25 kHz and - 5 V at 500 rnA by the .01-f.LF capacitor on pin 5 and the
5-kO resistor on pin 6.
20 VOLTS

4A

INPUT

5.6 kn

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25 kHz ':'

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Figure 9. TL493 Floppy Disk Power Supply

4-77

The center connection of the two 5.6-kn resistors on pins 13 and 14 establishes a
2.5-V reference voltage on pin 2, which is the inverting input of the voltage control error
amplifier. The voltage feedback to pin 1, the noninverting input, comes from the center
connection of the two 5.6-kn resistors located on the 5-V/2.5-A power supply output
terminal. Because this voltage supplies the logic circuits, it requires closer regulation.
The 24-V winding, on the other hand, is not critical as it furnishes voltage for the
stepping motor. The - 5-V supply is regulated separately with a uA 7905 three-terminal
regulator. In choosing components for this circuit, the same precautions taken in the
construction of any switching power supply should be observed; be careful of layout,
ground loops, and heatsinking of the power transistors. In the output section, where highfrequency rectifiers are needed, either Schottky or fast recovery diodes should be used.
For output capacitors, low equivalent series resistance (ESR) types should be considered.
The output ripple depends more on this resistance than on the capacitor value.

Transformer Construction
The transformer for this circuit was wound on a toroid core. The core used was 3C8
ferrite material (F-42908-TC). The winding layout is shown in Figure 10.

A

20V
INPUT

tE:
tE:

:3 tE
B

:

}

26VDC@2.5A

}

6VDC@2.5A

~;}

10

9 VDC @ 0.5 A

Figure 10. 1ransformer Winding Layout
'kansformer Winding Data

Primary A + B = 20 turns bifilar #20 HNP
Secondary C + D = 28 turns bifilar #20 HNP over A + B
Secondary E + F = 6 turns bifilar #20 HNP over C + D
Secondary G + H = 10 turns bifilar #26 HNP over E + F
NOTE: All windings to be center tapped.

4·78

DC Resistance
Winding
Winding
Winding
Winding

1- 3
0.11 n
4-6
0.11 n
7-9
0.025 n
10 - 12 = 0.15 n

TL594 12-V to 5-V Step-Down Regulator
The TL594 switching voltage regulator operates as a step-down converter in a
discontinuous mode. When the output current falls below a specified minimum value, the
inductor current becomes discontinuous. The advantages of a step-down converter in this
mode of operation are:
1. The ripple voltage at the output can be kept low, even in high-current designs.
2. The ratio of peak current in the switching device to output current is
determined by the inductor value and is typically low. For a specific output
current requirement, the current rating for the switching transistor can be
lower than for a transistor operating in a continuous mode.
3. Pulse-width modulation occurs with input voltage variations. Load variations
are compensated for by modulation of the dc current level in the inductor, as
well as by pulse-width modulation. This allows high efficiency to be
maintained over the entire load range (from 10 max to 10 min) .
The disadvantages of this type of converter are:
1. The size of the inductor used may result in a high-inductance value.
2. Transient response is impaired by high-inductance values.
3. Although peak current in the rectifier is reduced, losses due to reverse
recovery current are increased.
The complete circuit for the TL594 step-down regulator is shown in Figure 11. For
this application, the two switching transistors operate in phase with each other by
grounding the output control, pin 13. The switching transistors supply input to the
inductor, L for part of the oscillator cycle. For the remaining part of the oscillator cycle,
the voltage across the inductor reverses and diode DI starts conducting, maintaining
current flow in the inductor while the transistors are off (see Figure 12).

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4-79

2.2 mHo 10.4AI
r---------~-J~L~--f-------.--+5V

+12v------------------------f_--,
100 11

R7

MR852

Rl

5.6kl1

+ 1000 "F
C4

10V

R8

4.9kl1

R2

5.6 kl1

C3
R4

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1 kl1

Figure 11. TL594 12-V to 5-V Step-Down Regulator

o

INDUCTOR VOLTAGE

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(I)

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...0'ED

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1 =1

1.1 INDUCTOR VOLTAGE

=L
------r
--~

~---

INDUCTOR CURRENT

D

T

III IS THE PK·PK CURRENT

D - RECTIFIER CONDUCTING
T - TRANSISTOR CONDUCTING

::::I

(I)

0 - - - - - -- - - - - - - - - - -

Ibl INDUCTOR CURRENT

PULSE WIDTH
MODULATED SIGNAL

'ON' - - - . ,

'OFF'-

L

leI PULSE WIDTH MODULATED SIGNAL

Figure 12. 12-V to 5-V Series Switching Regulator Waveforms

4-80

The input supply through Rl to pin 12 is decoupled by capacitor C2. Capacitor C4
filters the output voltage. The timing components C3 and R6 set the oscillator frequency
to 15 kHz. The 2.2-mH inductor can be made on an RM7 ferrite core with 94 turns of #28
transformer wire.
Output-current limiting of 500 rnA is provided by sensing the overcurrent level with
Rll and feeding the resultant error voltage to the positive input of the current error
amplifier on pin 16. The negative input to this error amplifier is biased to 500 mV from
reference divider R2, R3, and R4. This resistor network also furnishes about 2.3-V bias to
the voltage control error amplifier. An output error voltage signal is taken from the
junction of R7 and R8 and fed to the positive input of the voltage control error amplifier.
The voltage control loop gain is set by feedback resistor R5.

Specifications
Input Voltage

12 V nominal (10 V to 15 V)

Output Voltage

5 V ± 10%

Output Ripple

50 mVpp

Output Current

400 rnA

Output Power

2 W at 5-V output

Short Circuit Protection

500-rnA constant current

Efficiency

typically 70%

The TL594 Control Circuit
The TL594 is a fixed frequency pulse-width-modulation control for switching power
supplies and voltage converters. The TL594 includes an adjustable oscillator, a pulsewidth modulator, and an error amplifier. Additional functions include over-current
detection, independent dead-time control, a precision 5-V reference regulator, and output
control logic which allows single-ended or push-pull operation of the two switching
transistors. Figure 13 shows a block diagram of the TL594.
Modulation of the output pulses is accomplished by comparing the sawtooth
waveform created by the internal oscillator on timing capacitor CT to either of two control
signals. The output stage is enabled when the sawtooth voltage is greater than the voltage
of the control signal. See Figure 14. As the control signals increase, the output pulse
width decreases. The control signals are derived from two sources: the dead-time control
and the error amplifiers. The dead-time comparator has a fixed offset of 10 mV which
provides a preset dead time of about 5%. This is the minimum dead time that can be
programmed with pin 4 grounded.

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4-81

PIN ASSIGNMENT
PIN NO.

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1.
2.
3.
4.
5.
6.
7.
8.

FUNCTION

FUNCTION

PIN NO.

ERROR AMP. 1, NON INVERTING INPUT
ERROR AMP. 1, INVERTING INPUT
COMPENSATION INPUT
DEAD TIME CONTROL INPUT
OSCILLATOR TIMING CAPACITOR
OSCILLATOR TIMING RESISTOR
GROUND
DRIVE TRANSISTOR l,COLLECTOR

9.

ORIVE TRANSISTOR 1, EMITTER
DRIVE TRANSISTOR 2, EMITTER
DRIVE TRANSISTOR 2, COLLECTOR
INPUT SUPPL Y
OUTPUT MODE CONTROL
STABILIZED REFERENCE VOLTAGE
ERROR AMP 2, INVERTING INPUT
ERROR AMP 2, NON INVERTING INPUT

10.
11.
12.
13.
14.
15.
16.

Figure 13. TL594 Block Diagram

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4.5V-

<

0.5 V-

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1
1

1

I

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en
PWM CONTROL RANGE, PIN 3
RESULTANT OUTPUT PULSE WITH
PIN 3 VOLTAGE AS ABOVE PIN 13WIRED FOR
SINGLE ENDED OPERATION

Figure 14. Output Pulses vs Sawtooth Control Voltage

4-82

The pulse-width-modulation (PWM) comparator generates the control difference
signal created by the input from either of the error amplifiers. One error amplifier is used
to monitor the output voltage and provide a change in control signal voltage. The other
error amplifier monitors the output current and its change in control voltage provides
current limiting.

Reference Regulator
The internal 5-V reference at pin 14 provides a stable reference for the control logic,
pulse-steering flip-flop, oscillator, dead-time-control comparator and pulse-widthmodulation circuitry. It is a band-gap circuit with short circuit protection and is internally
programmed to an accuracy of ± 5%.

Oscillator
The internal oscillator provides a positive sawtooth waveform to the dead-time and
PWM comparators for comparison with the various control signals. The oscillator
frequency is set by an external timing capacitor and resistor on pins 5 and 6. The oscillator
frequency is determined by the equation:
fose = _1_ (single-ended applications)
RTCT
The oscillator frequency is equal to the output frequency only for single-ended
applications. The output frequency for push-pull applications is one-half the oscillator
frequency as shown by the equation:
fose

=

1
(push-pull applications)
2 RTCT

There is a frequency variation of ± 5% between devices due to internal component
tolerances. The oscillator charges the external timing capacitor, CT, with a constant
current which is determined by the external timing resistor, RT. This circuit produces a
linear ramp voltage waveform. When the voltage across the timing capacitor reaches 3 V,
the circuit discharges and the charging cycle is initiated again.

Dead-Time and PWM Comparators

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Both the dead-time and PWM comparator functions use a single logic comparator
with parallel input stages. The comparator output is a pulse-width-modulated signal,
whose width is determined by comparison with the oscillator ramp waveform. The
comparator outputs drive the output control logic. A fixed 100-mV offset voltage input to
the dead-time comparator allows a minimum dead time between output pulses to be
maintained when the dead-time control input (pin 4) is grounded (Figure 15).

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4-83

0.2V
100mV

l~

DEADTIME OFFSET PIN 4 = 0 V

90%

OSCILLATOR RAMP, PIN 5
MAXIMUM OUTPUT PULSE WIDTH
SINGLE ENDED OPERATION, PIN 4

=0

V

Figure 15. Deadtime Comparator Operation
The full range of pulse-width control (0% - 90%) is available when the dead-time
control voltage (pin 4) is between 3.3 V and 0 V. The relationship between control voltage
and maximum output pulse width is essentially linear. A typical application for this may
be in a push-pull converter circuit where overlap of the conduction times of power
transistors must be avoided.
The PWM comparator input is coupled internally to the outputs of the two error
amplifiers. This input is accessible on pin 3 for control loop compensation. The output
pulse width varies from 90% of the period to zero as the voltage present at pin 3 varies
from 0.5 V to 4.5 V (Figure 14).

Error Amplifiers

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Both error amplifiers are high-gain amplifiers which operate as single-ended,
single-supply amplifiers, in that each output is active high only. This allows each amplifier
to pull up independently for a decreasing output pulse-width demand. With the outputs
ORed together, the amplifier with the higher output level dominates. The open-loop gain
of these amplifiers is 60 dB. Both error amplifiers exhibit a response time of about 400 ns
from their inputs to their outputs on pin 3. Figure 16 shows the amplifier transfer
characteristics and a Bode plot of the gain curves .

g.

Output Logic Control

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4-84

The output control logic interfaces the pulse-width modulator to the output stages.
In the single-ended mode (both outputs conducting simultaneously), the pulse-widthmodulated signal is gated through to both output stages when the output control (pin 13) is
connected to ground.

4

3
Va

2

10

20

Vin(mV)
AMPLIFIER TRANSFER CHARACTERISTICS

80

ai 60
~

:2

40

(!)

20

~

0

lK

10K

lOOK

1M

FREOUENCY (Hz)
AMPLIFIER BODE PLOT

Figure 16. Amplifier Performance Curves
For push-pull operation (each output stage conducting alternately), the output
control (pin l3) is connected to the internal reference voltage (pin 14) enabling the pulse
steering flip-flop. The flip-flop is toggled on the trailing edge of the pulse-widthmodulated signal gating it to each of the outputs alternately; therefore, the switching
frequency of each output is one-half the oscillator frequency. The output control (pin 13)
must never be left open. It may be connected to the internal voltage reference (pin 14) or
ground (pin 7).

The Output Driver Stages
The two identical Darlington output drivers may be operated in parallel or push-pull
mode. Both the collector and emitter terminals are available for various drive
configurations. VCE(sat) of each output at 200 rnA is typically 1.1 V in common-emitter
configuration and 1.5 V in common-collector configuration. These drivers are protected
against overload but do not have sufficient current limiting to be operated as current
source outputs.

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4-85

Soft Start
Use of a soft-start protection circuit is recommended. This circuit prevents current
surges during power-up and protects against false signals which might be created by the
control circuit when power is applied. Implementing a soft-start circuit is relatively simple
using the dead-time control input (pin 4). Figure 17 shows an example.
Initially, capacitor Cs forces the dead-time control input to follow the internal 5-V
reference which disables both outputs (100% dead time). As the capacitor charges through
RS, the output pulse width increases until the control loop takes command.

TYPICAL VALUE
1.0j.lF

--+ Cs

TL494
...-

........ 4

DEAD-TIME CONTROL

TYPICAL VALUE
<100 kn

--+ RS

Figure 17. Soft-Start Circuit

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Overvoltage Protection
The dead-time control input (pin 4) also provides a convenient input for over-voltage
protection, which may be sensed as an output voltage condition, or input voltage
protection as shown in Figure 18.

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MONITORED SUPPLY RAIL

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TL494

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4

DEAD-TIME CONTROL

Figure 18. Overvoltage Protection Circuit

4-86

A TL431 is used as the sensing element. When the monitored supply rail voltage
increases to the point that 2.5 V is developed across R2, the TL431 conducts, Q1 becomes
forward biased, and the dead-time control is pulled up to the reference voltage which
disables the output transistors.

Designing a Power Supply 5-V/lO-A Output
Design Objective
This design uses the TL594 integrated circuit based on the following parameters:

Vo
VI
10

= 5V
=

=

32 V
lOA

f = 20 kHz switching frequency
VR = 100 mV peak-to-peak (Vripple)
6.IL = 1.5 A inductor current change

Input Power Source
The 32-V dc-power source for this supply uses a 120-V input, 24-V output
transformer rated at 75 VA. The 24-V secondary winding feeds a full-wave bridge rectifier
followed by a 0.3-0 current limit resistor and two filter capacitors, as shown in Figure 19.
BRIDGE

~~~~----

+
__----32V

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20.oo01.lF'[

]O.OOOI.lF

~

-

Figure 19. Input Power Source

=

I rectifier(avg)

V secondary

= (~~)

X

X

Io

V2 =

= :2 ~

24 V

X

V2 =

X 10 A

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The output current and voltage are determined by the following equations.
V rectifier

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34 V

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C

= 1.6 A

The 3-A/50-V full-wave bridge rectifier meets these calculated conditions.
Figure 20 illustrates the switching and control section.

4·87

TL494

50 WATT POWER SUPPLV[5 V

@

IDA OUTPUT]

~P~T>------------------1~-----4~-----'-{

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R9

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R11

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Figure 20. Switching and Control Section

Control Circuits
Oscillator
The TL594 oscillator frequency is controlled by connecting an external timing
circuit consisting of a capacitor and resistor to pins 5 and 6. The oscillator is set to operate
at 20 kHz using the component values calculated by the following equations.

4-88

where:
RT = Value of timing resistor
CT = Value of timing capacitor
Choose CT

=

0.001 J.LF and calculate RT.
1

1

20

X

103

X

0.001

X

10- 6

=

50 kn

Error Amplmer
The error amplifier compares a sample of the 5-V output to a reference and adjusts
the pulse-width modulator to maintain a constant output as shown in Figure 21. The
TL594's internal 5-V reference (pin 14) is divided to 2.5 V by R3 and R4. The output
voltage error signal is also divided to 2.5 V by R8 and R9. If the output must be regulated
to exactly 5 V, a lO-kn potentiometer may be used in place of R8 to provide an adjustment
control. To increase the stability of the error amplifier circuit, the output of the error
amplifier is fed back to the inverting input through R7, reducing the gain to 100.
OUTPUT SAMPLE

I

R3

TL494 I

R5

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5100

I
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Vo

R4

5.1 kO

R7

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Figure 21, Error Amplifier Section

CurnntLindtAmplifler
The power supply was designed for a lO-A load current and an IL swing of 1.5 A;
therefore, the short circuit current should be
ISC =

10 +

Ii = 10.75 A

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The current limit portion of the circuit is shown in Figure 22. Resistors R1 and R2
set a reference of about 1 V on the inverting input of the current limit amplifier. Resistor
Rll, in series with the load, applies 1 V to the noninverting terminal of the current limit

4-89

amplifier when the load current reaches 10 A. The output-pulse width will be reduced
accordingly. The value of Rll is calculated as follows:

Rll

=~ =
10 A

0.1 fi

n

,",v OUTPUT~-=r-

0.1
~"N\...-4I"""'_4-LOAD-++
R11

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TL494

I
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Figure 22. Current Limit Circuit
Soft Start and Dead Time

To reduce stress on the switching transistors at startup, the startup surge which
occurs as the output filter capacitor charges must be reduced. The availability of the deadtime control makes implementation of a soft-start circuit, as shown in Figure 23, relatively
simple.
The "soft-start" circuit allows the pulse width at the output to increase slowly, as
shown in Figure 23, by applying a negative slope waveform to the dead-time control input
(pin 4). Initially, capacitor C2 forces the dead-time control input to follow the 5-V
reference regulator, which disables the outputs (100% dead time). As the capacitor charges
through R6, the output-pulse width slowly increases until the control loop takes
command. With a resistor ratio of 1:10 for R6 and R7, the voltage at pin 4 after startup will
be 0.1 x 5 V or 0.5 V.
The soft-start time is generally in the range of 25 to 100 clock cycles. If we select 50
clock cycles at a 20-kHz switching rate, the soft-start time is calculated as follows:
T

1
= -1 = - - =
f

20 kHz

50 j.Ls per clock cycle

The value of the capacitor is then determined by
C2

=

soft start time
R6

=

50 j.LS x 50 cycles = 2 5 F
. j.L
1 kfi

This helps to eliminate any false signals which might be created by the control
circuit as power is applied.
4-90

r-- --------I
I
1+5V=VR

9.1 kn

OSCILLATOR
RAMP

/till

OSC

RT

10l'F +
C2

R6

1 kn
TL494

PIN 4 VOLTAGE
(

--'""-'.

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r

OSCILLATOR RAMP
VOLTAGE,PIN5

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o

Inductor Calculations

o

The switching circuit used is shown in Figure 24. The size of the inductor (L)
required is calculated as follows:

'm

d

=

Duty Cycle

5V
= -Vo = -

VI

32 V

cC)
G)

c

0.156

f = 20 kHz (Design Objective)

4-91

ton = time on (Sl closed) =
toff = time off (Sl open) =

i

x d = 7.8 J.LS

i-ton

= 42.2 J.Ls

L = (VI-VO) x ton = (32 V-5 V) X 7.8 J.LS = 1404 H
aIL
1.5 A
. J.L
L

= 140 J.LH
INDUCTOR CALCULATIONS
L

i

C

Vo

~
Figure 24. Switching Circuit

Output Capacitance Calculations
Once the filter inductance has been calculated, the value of the output filter capacitor
is calculated to meet the output ripple requirements. An electrolytic capacitor can be
modeled as a series connection of an inductance, a resistance, and a capacitance. To
provide good filtering, the ripple frequency must be far below the frequencies at which the
series inductance becomes important; so, the two components of interest are the
capacitance and the effective series resistance (ESR). The maximum ESR is calculated
according to the relation between the specified peak-to-peak ripple voltage and peak-topeak ripple current.
ESR(

max

) =

aVo (. 1)
0.1 V
nppe = - - = 0.067 n
aIL
1.5 A

The minimum capacitance of C3 necessary to maintain the V0 ripple voltage at less
than the 100-mV design objective was calculated according to the following equation.
_
aIL
C3 - 8 faVO

1.5 A
8 x 20 x 103 x 0.1 V

=

94

F
J.L

A 220-J.LF, 60-V capacitor is selected because it has a maximum ESR of 0.074 nand
a maximum ripple current of 2.8 A.

4-92

Transistor Power Switch Calculations
The transistor power switch was constructed with a TIP30 p-n-p drive transistor and
a TIP73 n-p-n output transistor. These two power devices were connected in a p-n-p hybrid
Darlington circuit configuration as shown in Figure 25. The hybrid Darlington must be
saturated at a maximum output current of 10 + alL/2 or 10.8 A. The Darlington hFE at
10.8 A must be high enough not to exceed the 250-mA maximum output collector current
of the TL594. Based on published TIP30 and TIP73 hFE specifications, the required
power switch minimum drive was calculated by the following equations to be 108 rnA.

= 10
at IC of 12.0 A = 10

hFE(Q1) at IC of 1.2 A
hFE(Q2)

10

iB ;::=

+

aIL
2
hFE(Q2) x hFE(Ql)

;::= 108 rnA

The value of RIO was calculated by the following equation.
RIO :::::; VI - (VBE(Ql) + VCE(TL594)) = 32 - (1.3 + 0.7)
iB
0.108
RIO :::::; 277

n
32V-"'--"'~

02
TIP73

R11

100 n

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C

01

all
10+- - 10.8 A
2

TIP30

----- -,

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TL494

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R10

270

n

'Ui
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C

_ _ _ _ _ _ ..J

-

Figure 25. Power Switch Section
4-93

Used on these calculations, the nearest standard resistor value of 270 n was selected
for RIO. Resistors Rll and R12 pennit the discharge of carriers in the switching transistors
when they are turned off. The power supply described demonstrates the flexibility of the
TL594 pulse-width-modulation control circuit. This power supply design demonstrates
many of the power supply control methods provided by the TL594 as well as the versatility
of the control circuit.

TL497A Switching Voltage Regulator
The TL497A is a fixed-on-time, variable-frequency voltage regulator controller. The
block diagram of the TL497 A is shown in Figure 26. The on-time is controlled by an
external capacitor connected between the frequency control pin (pin 3) and ground. This
capacitor, CT, is charged by an internal constant-current generator to a predetennined
threshold. The charging current and threshold vary proportionately with Vee; thus, the
on-time remains constant over the allowable input voltage range.
BASE
BASE DRIVE

(11)t
(12)t

CUR LIM SENS

FREQCONT

OSCIL·
LATOR

(3)

INHIBIT
(10)

COMP INPUT

SUBSTRATE

CATHODE

COL OUT

EMIT OUT
(6)

~

(7)

ANODE

tThe Base pin (#11) and Base Drive pin (#12) are used for device testing only. They are not normally
used in circuit applications of the device.

Figure 26. TL497A Block Diagram
The output voltage is controlled by two series resistors in parallel with the supply
output. The resistance ratios are calculated to supply 1.2 V to the comparator input (pin 1)
at the desired output voltage. This feedback voltage is compared to the 1.2-V bandgap
reference by the high-gain error amplifier. When the output voltage falls below the desired
voltage, the error amplifier enables the oscillator circuit, which charges and discharges CT.
The n-p-n output transistor is driven "on" during the charging cycle of CT. The
internal transistor can switch currents up to 500 mAo It is current driven to allow operation

4·94

from either the positive supply voltage or ground. An internal diode matched to the current
characteristics of the output transistor is included on the chip and may be used for blocking
or commutating purposes.
The TL497 A also contains current-limiting circuitry which senses the peak currents
in the switching regulator and protects the inductor against saturation and the output
transistor against overstress. The current limit is adjustable and is set by a single-sense
resistor between pins 13 and 14. The current-limit circuitry is activated when 0.5 V is
developed across current-limit resistor RcL.
RCL

L

L
~

I
14

13

Vo

Vo

I

8

10

14

13

10

8

Rl

I

2

3

4

;;;r:: c

-----4

TL497
1

Rl

5

6

TL497

7

R2
2

3

1

4

5 6

7

/L

fT

(a)

(b)

STEP DOWN
POS -+ POS
(+)

;::r:: '

1.2kn

1

L

;::~CT

~

R2
1.2kn

STEP UP
POS -+ POS

VI> (+) Vo

(+ VO> (+) VI

I
14

r

8

10

13

.

TL497

1

/

2

3

4

~

-¥

R2
1.2 kn

5

;;; r:: CF

o

!

CD

"CI

'iii
-

;; r,;_ L

C

'

Rl
~~

..
U)

Vo

CT

c

o

(.)

c

-

(c)

INVERT
POS -+ NEG
V+

-+

en
'iii
CD
C

V-

Figure 27, Basic Power Supply Configurations

4-95

The TL497 A contains all the active elements required for constructing a singleended dc-to-dc converter. The output transistor and the rectifier are uncommitted allowing
maximum flexibility in the choice of circuit configuration. The TL497 A's primary feature
is design simplicity. Using six external components; three resistors, two capacitors, and
one inductor, the step-up, step-down, and inverting power supplies shown in Figure 27
may be constructed.
STEP-UP
POS ~ POS

STEP-DOWN
POS ~ POS

INVERTING
POS~NEG

+Vo> +VI
+VI> +Vo
Step-Down Switching Regulator

+VI> -Yo

The circuit in Figure 28(a) illustrates the basic configuration for a step-down
switching regulator. When switch SI is closed, the current in the inductor and the voltage
across the capacitor start to build up. The current increases while switch SI is closed as
shown by the inductor waveform in Figure 28(b). The peak current in the inductor is
dependent on the time SI is closed (ton).
When SI opens, the current through the inductor is Ipk. Since the current cannot
change instantaneously, the voltage across the inductor inverts, and the blocking diode
(D1) is forward biased providing a current path for the discharge of the inductor into
the load and filter capacitor. The inductor current discharges linearly as illustrated in
Figure 28(b).

S1

o
CD

rn
cC"
:::s

L

S1~~----1Ir----~4
VI

01

o
o
:::s

rn

a:CD

;....

0"
:::s
rn

4-96

(a) BASIC STEP-DOWN REGULATOR

t-..j-~ton~to-J
CHARGE !.-OISCHARGE--.!

(b) INDUCTOR CURRENT WAVEFORM

Figure 28. Step-Down Switching Regulator
For the output voltage to remain constant, the net charge delivered to the filter
capacitor must be zero. The charge delivered to the capacitor from the inductor must be
dissipated in the load. Since the charge developed in the inductor is fixed (constant ontime), the time required for the load to dissipate that charge will vary with the load
requirements. It is important to use a filter capacitor with minimal ESR. Note, however,
some ripple voltage is required for proper operation of the regulator. Figure 29 shows a
positive, step-down configuration both with and without an external pass transistor.
Design equations for calculating the external components are included.

RCL

L

Va

~

T
8

10

13

14

R1

;;::~CF

TL497

1

2

I

4

3

5

6

R2
1.2 kn

7

I

;;:: ~

BASIC CONFIGURATION
(IpK V=3VII;L

+~

o
Sljf-CLOSEO

o

*'
I

I

I

I

i
OPEN-----tj
I

_IrCH~:GE~+~ jt-IDLE--+I
\....DISCHARGE

to
(a) BASIC STEP-UP REGULATOR CIRCUIT

(b) INDUCTOR CURRENT WAVEFORM

Figure 30. Step-Up Switching Regulator

Inverting Configuration

c
CD
In
c'
::s
n
o

::s

In

c:CD
&;

r+

0'
::s

In

4-98

The inverting regulator is similar to the step-up regulator. During the charging cycle
of the inductor, the load is isolated from the input. The only difference is in the potential
across the inductor during its discharge. This can best be demonstrated by a review of the
basic inverting regulator circuit (Figure 32).
During the charging cycle (Sl closed), the inductor (L) is charged only by the input
potential, similar to the step-up configuration. In the inverting configuration, the input
provides no contribution to the load current during the charging cycle. The maximum load
current for discontinuous operation will be limited by the peak current, as observed in the
step-up configuration. The inductor current waveform looks identical to the waveform
demonstrated in the step-up configuration [see Figure 30(b)].
Figure 33 shows the inverting applications both with and without an external pass
transistor. Design equations are also included. Note that in the inverting configuration, the
internal diode is not used. An external diode must be used because pin 4 (substrate) must
be the most negative point on the chip. The cathode of the internal diode is also the cathode
of a diode connected to the substrate. When the cathodes are at the most negative voltage
in the circuit, there will be conduction to the substrate resulting in unstable operation.

--L

T
14

Va

r-

13

8

10

R1

:;;:: ~CF

TL497

1

2

I

4

3

5

6

7

I

L-

R2
1.2kn

*CT

1
-~

BASIC CONFIGURATION
(IpK <500 rnA)

...

L
~

©~

I
14

10

13

8

R1

;;::~C F

TL497

1

2

3

4

Va

•

R2
1.2kn

5

;: ~CT

II)

C

o
!

--

',t:;

CD
"C

EXTENDED POWER CONFIGURATION
(USING EXTERNAL TRANSISTOR)

'r;;
C

o

DESIGN EQUATIONS

(J

+~~J

•

IpK = 2 ILOAD max 1

•

VI
L (.uH) = ton (.us)
IpK

Choose L (50 to 500 .uHI. calculate
ton (25 to 150 .us)

c
en

'r;;
•

R1 = (VO - 1.2) kn

•

0.5 V
RCL = - IpK

•

CF=~~--~~~

(lPK -ILOAD)2
(Vripple) 2 IpK

CD

o

ton VI

x--

Vo

Figure 31. Positive Regulator, Step-Up Configurations
4-99

Iload ..

S1

+!
VI

iC
L

~

C

+

Vo

Figure 32. Basic Inverting Regulator Circuit

Design Considerations
An oscilloscope is required when building a switching regulator. When checking the
oscillator ramp on pin 3, the oscilloscope may be difficult to synchronize. This is a normal
operating characteristic of this regulator and is caused by the asynchronous operation of
the error amplifier to that of the oscillator. The oscilloscope may be synchronized by
varying the input voltage or load current slightly from design nominals.
High frequency circuit layout techniques are imperative. Keep leads as short as
possible and use a single ground point. Resistors RI and R2 should be as close as possible
to pin I to eliminate noise pick-up in the feedback loop. The TL497 A type of circuits do
not need "hi-Q" inductors. They are, in fact, not desirable due to the broad frequency
range of operation. If the "Q" is too high, ringing will occur. If this happens, a shunt
resistor (about l-kO) may be placed across the coil to damp the oscillation.

cCD

en

cE'
::::I

o
o
::::I

en

0:

...CDCD

...0'
::::I

en

4-100

While not necessary, it is highly desirable to use a toroidal inductor as opposed to a
cylindrically wound coil. The toroidal type of winding helps to contain the flux closer to
the core and in tum minimize radiation from the supply. All high current loops should be
kept to a minimum length using copper connections that are as large as possible.

-L

RCL
~

T
14

I
13

10

+

-:!:-

8

R'
TL497

1

I

R1
1.2 kn

5

4

3

2

;:~CF

~l

Vo

1

*CT

1
BASIC CONFIGURATION

(lPK <500 rnA)
L
~------------e-~~~e-~--e--,+

14

13

10

8

R2

TL497

2

3

4

R1
1.2kn

5

L--+----------~--~~--

__--~--vo

II
en
c:

o
'.j:i

..
as

Q)

"'C

EXTENDED POWER CONFIGURATION
(USING EXTERNAL TRANSISTOR)

'ec:n
o
o

DESIGN EQUATIONS

•

•

'pK = 2 'LOAD

L(ItH) =

V,
-

c:
en

max~ + ~~]
•

R2= (VO -1.2) kn

•

0.5V
RCL=--

•

CF =

'en
o

Q)

ton (Its)

'pK
Choose L (50 to 500 ItH), calculate

IPK

ton (25 to 150 Its)

_O.:..P;.:.K_-_'..=L:.::O:::A:..:D:....)2
(Vripple) 2 IPK

ton V,

x--

Vo

Figure 33, Inverting Applications
4-101

A Step-Down Switching Regulator Design
Exercise with TL497A
The schematic of a basic step-down regulator is shown in Figure 34. This regulator
will have the following design goals:

VI

15 V

Vo

5V
200 rnA

10

<

Vripple

1.0% or 50 mV (1.0% x 5 V)

Calculations:
IpK

14

2 IL max

=

400 rnA

10

13

8
R1

TL497A

•

R2

1

2

3

4

5

6

7

1.2 kn.

oCD
(11

~:
::J
(")

Figure 34, Basic Step.Down Regulator

o

::J
(11

a:CD

.....
I»

0'
::J

(11

4-102

For design margin, IpK will be designed for 500 rnA which is also the limit of the
internal pass transistor and diode .

.·.lpK

= 500 rnA

The next step will be to select ton. You may select a timing capacitor to match an
inductor you may already have. You may also assume an on-time and calculate the
inductor value. We will assume an on-time of 20 ""s.

ton

20 f1s
VI - Vo
IpK

L

X

ton

15 X 5
0.5

f1s

X

20

400 f1H

To set the TL497 A for 5-V output:
R2

1.2 kO (fixed)

Rl

(5 - 1.2) kO

=

3.8 kO

To set current limiting:
0.5

RCL

500

IL

RCL

0.5
10- 3

10

X

10

For the on-time chosen, CT can be approximated:
12

ton

f1S

240 pF
or it may be selected from a table in the data sheet.
To determine filter capacitor (CF) for desired ripple voltage:
(IPK - IL)2 X ton VI
(Vripple) 2 IpK
V0

CF
CF

=

(0.5 - 0.2)2
(0.05) 2 X 0.5

X

20

X

en
10- 6
5

X

15

=

108 f1F

c
o

'+,

ca
~

Q)

We selected CF to be 120 f1F, the next higher standard value. Figure 35 illustrates the
regulator with the calculated values applied to it.

"0

A 150-f1F filter capacitor may be used as a prefilter as well as a O.01-/-lF disc
capacitor to take care of any transients on the incoming VI rail. For peak currents greater
than 500 rnA, it is necessary to use an external pass transistor and diode. Such a technique
is illustrated in Figure 36, which is an automotive power supply. With a 12-V battery, this
step-down regulator supplies 5 V at 2 A.

(,)

'en
C
o
c

C)

'en
Q)
c

Figure 37 illustrates a basic step-up regulator. This design steps up the output
voltage from 5 V to 15 V. The equations for determining the values of the external
components are provided in Figure 31.

4-103

+V,

n. ",

400 pH

10

~

T

(15V

14

10

13

8

150 pF

3.8kO
-::::-12OpF
.... 1" 5OV

TL497A

1

2

3

I

4

5

7

6

VO=5V

1.2 kO

I 0=200mA

I

~240
'" pF

;:

+

VRIPPLE = 50 mV

Figure 35. 15-V to 5-V Step-Down Regulator
V,=
7 V TO 12 V
0.1 0
+ - ....- ....l1/li....,.

75pH

VO=5V

+
1N5187D

14

13

10

8

3.8 kO

TL497A

150pF

2

3

4

1000 pF
1.2 kn

5

cCD
en

cC"
::s

Figure 36. Step-Down Regulator

n
o
::s

en

c:
CD

;r+

0"
::s

10

V,
" = 2.54 mA
P, = 1.27 W

200 pH
,....,.,.,.,.,.

Vo = 15V

T
14

+

r13

8

10

13.8 kn

120 pF;: ~

10= 75mA
Po =1.125W
;:,12 pF

TL497A

en

1

I

2

3

4

g40
=1'pF

5

6

7

I

L-

1.2kn

1
-~

EFFICIENCY = 71%

Figure 37. 5-V to 15-V Switching Regulator
4-104

-

Design and Operation of an Inverting Regulator Configuration
Figure 38 illustrates a basic inverting regulator designed to have - 5-V output with
the design equations in Figure 33.

+ 5-V input using
Conditions:

VI
Vo

10
Vripple

5V

-5 V
100 rnA
1.0% or 50 mV (1% x 5 V)

Calculations:

2lL(max) (1
IpK

Assume

ton

CT(pP)

+ I

~~ I)

400 rnA (for design margin use 500 rnA)
20 IJ-S
12

ton

IJ-S

CT

240 pF

L

VI
ton
IpK

5
x 20 = 200 IJ-H
0.5

To set the output voltage:

II
U)

R2

1.2 ko.

R1

(5 - 1.2) ko. = 3.8 ko.

To set the current limiting:

RCL

0.5
0.5
- = - =10.
0.5
IpK

RCL

1 0.

Cp

(lpK - IL)2 x ton VI
(Vripple) 2 IpK
Vo

C

o
',ij

..
as

CD

"C

'mC
o

(J

cC)

'mCD

c

4-105

To determine Cfilter for desired ripple voltage:
Cp

=

ton VI

(IpK - IL)2 X
(Vripple) 2IpK

I Vo I

(0.5 - 0.1)2 X 20 X 10- 6 X 5
(0.05)2 X 0.5
I-5I
Cp

=

68 IJ.F)

200l'H

10

+VI
(5VI

~

I

T

11=165mA
PI =825 mW
120l'F

64 IJ.F (nearest standard value

14

13

10

8

-: r-1N4001

~~

~

10= 100mA
Po= 500mW
VRIPPLE <50 mV

3.8 kO

Efficiency = 61%

:;;::,

:;;:: ~68 I'F

TL497A
1.2kO
1

2

I

3

4

5

:::- 240I pF

:;;:: r-

Vo =-5V

.'-

NOTE - Do not use internal diode (Pins 6, 7) on an inverting circuit.

Figure 38.

+ 5-V to

- 5-V Switching Regulator

Adjustable Shunt Regulator TL430 - TL431

c

CD

o

US'
::::s

n
o
::::s

o

a:CD
;r+

0'
::::s

o

4-106

The TL430 and TL431 are three-terminal "programmable" shunt regulators. The
devices are basically the same except the TL431 contains a diode connected between the
emitter and collector of the output transistor. The standard symbol and block diagram are
shown in Figure 39.
The circuit consists of a bipolar operational amplifier driving an n-p-n transistor.
The reference on the TL430 is a band-gap reference (not temperature compensated). The
TL431 has a true-temperature compensated band-gap reference and is more stable and
accurate than other shunt regulators. The TL431 also has a diode across the emittercollector of the n-p-n output transistor. If the cathode goes negative, the diode conducts
around the transistor, emulating the performance characteristics of a normal zener diode.
The basic operating characteristics are shown in Figure 40.

TL430 - TL431

M - - - CATHODE

ANODE

REF

(a) SYMBOL
CATHODE

...----4......... -..,

*
I

REF - - - 1

TL431 ONLY

I
_J

ANODE

(b) BLOCK DIAGRAM

Figure 39. Tl430/TL431 Adjustable Shunt Regulators
TL430. TL431 PROGRAMMABLE ZENERS
50
45
RS

40

VIN

Vz

35

TL431

en

c
o
'';;
f!Q)

30

R1

25
20

Vref
R2

15

"C

10

C

'US

o

o

5
0
0

•
•
•
•

TEMPERATURE COMPENSATED

2
3
VOLTS/DIV

~

4
TL431

LOW DYNAMIC IMPEDANCE

200 ppm/"C

100ppm/"C

TYPICAL Vref

1.5 OHMS

0.2 OHMS

REGULATES FROM 1.0 -100 mA OVER
ADJUSTABLE VOLTAGE RANGE

2.75 V

2.5 V

2.75-30 V

2.5-36 V

5

cC)

'US
Q)
C

Figure 40. Basic Operating Characteristics
4-107

Their excellent thermal stability make these devices extremely attractive as a
replacement for high-cost, temperature-compensated zeners. As seen in Figure 41, the
TL431 offers improved characteristics, even at low voltages. Since the TL431 operates as
a shunt regulator, it can be used as either a positive or negative voltage reference. The
TL431 has an equivalent full-range temperature coefficient of 50 ppmJ°e (typical) and has
low output noise voltage. Note in the graph (Figure 41) that for a nominal 2.495-V
reference the curve is essentially flat from ooe to 700 e. Depending upon the zener
voltage, the TL431 also has an extremely low dynamic impedance of about 0.2 .0,
compared to a standard zener diode's dynamic impedance of about 30 to 60 n.
A 2.5-V reference voltage is developed across R2 as shown in Figure 42. lref, the
current input at the reference terminal, is about 10 fJ.A. To maintain a steady reference, it
is advisable to allow 1 mA of current flow through series resistors Rl and R2. This will
assure a stable reference voltage independent of lref variations. The TL431 is available in
either the commercial temperature range of 0° - 70 0 e or the military temperature range of
- 55° to + 125°e.
R

=

VI -

(Vbe

+

YO)

IR

c
CD

R

=

32 - (2 + 24)
10 rnA

Vo

=

(1

Rl

=

21.4 kn

R2

=

2.5 kn

+

=

600 .0

~~) Vref

(I)

cEo
::s

oo

::s
is:

(I)

....
CD

C»

c)"
::s
(I)

4-108

The circuit in Figure 43 uses a TL431 as a regulator to control the base drive to a
TIP660 series pass transistor. For good reference stability, a current flow of about 1 mA
(12) though the resistor divider is recommended. A 2.5-V reference voltage is developed
across R2, and Rl will develop a voltage drop of 21.5 V. The Darlington power transistor
is used because of the reduced base drive requirement of the TIP660 which has a Vbe
(max) of about 2 V. The hFE at 2.5-A Ie is about 1000, so it would only require about 2.5
rnA of base drive to produce 2.5 A of output current. In calculating the value of the current
limit resistor, R3, we assume about 7.5 rnA of current through the TL431. The value of
R3, therefore, would be 600 .0 and the current about 10 rnA, so a 1!2-W resistor will
suffice. This is a simple method of designing a medium output current power supply using
only four components plus the series pass transistor.

>

2600

w

2580

!

Vref MAX = 2550 mV

t:l

«

I...I

0

>

I-

::J
a..
2

Vref TYP = 2495 mV

w

U

2

w
~
w
II.
w

...I!!

~

>

2460
2440
2420
2400
-55

-25

0

25

50

75

100

125

TA AMBIENT TEMPERATURE (OCI

Figure 41, Reference Input Voltage vs Ambient Temperature
Vz

R1 ~

..._._Ire:-f_ _..-l:~ TL431

i

R2

vref

+

-~
Vz - Vref

[1 +

Vref - 2.5 V

:~J

II
en

C

o

~

Figure 42, Basic Operational Circuit

!CD

."

'US
C

o

(.)

c

en
'US
CD
C

4-109

TIP660

>r----....-VO=24 v
R3

600

n

2.5mA

112

..

~10mA
IR

--+

21.5 kn

R1

1 7 •5mA

TL431r~~+_R~E_F________•
A

2.5 kn

R2

Figure 43. Series Regulator Circuit

Shunt Regulator Applications (Crowbar)

•

o

CD

To protect solid-state electronic equipment from overvoltage due to a power-supply
component failure, it is sometimes desirable to use a "crowbar" circuit. When a preset
voltage is exceeded, the TRIAC turns on, shorting the output and blowing the fuse on the
input side of the crowbar circuit. The circuit in Figure 44 is set to trip when Vo reaches
27 V. When that occurs, the reference voltage should be 2.5 V which turns on the TL431,
thus biasing the SCR low. This turns the SCR on and immediately blows the safety fuse on
the circuit input, thus protecting the equipment using this power supply.

VL

=

(1

+ :~) Vref

(I)

ca·
~

o
o
~
(I)

c:CD
...I»

...o·

4AMP

r

"

SET FOR 27·V

FUSE
100
24.5 kO

n
MT1

R1

Vref

24V -VI

~

(I)

TL431

1

24
+ Vo

2.5 kO

TRIAC
TIC226A
~ (8A-100 VI
MT2

R2

Figure 44. Shunt Regulator in Crowbar Circuit
4-110

Controlling Vo of a Fixed Output Voltage Regulator
Sometimes, it is necessary to have a regulated output voltage different from that for
which the regulator is designed. This may be accomplished with any three-terminal
regulator, although it should be noted that the lowest obtainable voltage will be 2.5 V for
the TL431 plus the voltage of the three-terminal regulator. In the circuit in Figure 45, the
lowest possible regulated voltage would be 7.5 V (2.5 V for the TL431 + 5 V for the
7805). This particular circuit provides 9-V output using a uA 7805 three-terminal
regulator.
Note: Minimum Vo
V0 = (1 +

=

Vref

+ 5V

~~) Vref
+

I
I

7805

I
I

+

R1

VI
14.0 V

6.5 kn
Vo

C

~~

REF

9.0V

-r-

A

R2

NOTE: MINIMUM Vo - Vref
Vo

2.5 kn

+ 5.0 V

=(1 + :~ ) vref

CI)

c:

o

Figure 45. Fixed Output Shunt Regulator

"';:::;

ca
~

Current Limiter

Q)

Figure 46 is an example of a current limiter designed to limit the current from a 12-V
supply to 1. 5 A using a TIP31 n-p-n transistor as the pass element. The value ofRI is calculated
from the equation in Figure 46. The current through Rl is split almost equally in this circuit,
with about 30 rnA going to the TL431, and 30 rnA for base drive to the TIP3l. With a current
load of 6 rnA and an Rl value of 128 a, a 112- W resistor is sufficient. When the voltage
across the current limit resistor (RCL) reaches 2.5 V (TL431 reference voltage), the base
drive to the TIP31 is reduced and the output current is limited to 1.5 A.
Rl = VI - (Vbe + VRCL) = 12
11
2.5V-I
RCL -- -Vref -- - .7
IL
1.5 A

(1.8 + 2.5) = 128
0.06

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4-111

TIP31
VBE = 1.8 V
VI----.e_.....,..
RCL

+12 V
128 n

R1

1.7 n

+

121
SOmA

~

30 rnA

~

Figure 46. Current Limiter

Voltmeter Scaler
The circuit in Figure 47 is a voltmeter scaler (or multiplier) to extend the range of a
0- to 10- V voltmeter to 40 V. Most multiplier circuits extend the range with 0 V being the
low reading on any given scale. This circuit actually divides the 40-V total range into

4 separate 10-V scales.
With the selector switch in position #1, the reference input of the TL431 is bypassed
and the TL431 does not influence circuit operation. The meter is effectively connected
directly to the voltage being measured. This scale would be the normal meter range of
o to 10 V.

,....------02

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cO·

~--03

75kn

4

175
kn

C

TL431

R

::::J

oo

A

25kn

::::J

In

a:CD
D1
....

2r
::::J
In

SWITCH
POSITION

1

2

METER
RANGE
VOLTS

0·10

10·20

3

4

20·30 30·40

Figure 47. Voltmeter Scaler

4·112

METER
INPUT

When in position #2, a 75-kO and a 25-kO resistor are added in series across the
anode and cathode of the TL431. The voltmeter will remain near zero until the input
reaches 10 V. At this time, there is 2.5 V between the reference terminal and anode which
causes the voltmeter to start reading at 10 V. It will continue reading on this scale until it
reaches full scale, which is 20 V.
This sequence is repeated in 10-V steps until position #4 is reached. This circuit is
very useful when expanded-scale voltmeter multiplication is required. The precision of the
scaler depends upon the accuracy of the resistors.

Voltage-Regulated, Current-Limited Battery Charger
for Lead-Acid Batteries
There are a number of approaches to recharging lead-acid batteries. Many will
return the battery to service, but fail to fully rejuvenate the battery. To keep a battery fully
charged, and attain maximum battery life, proper charging techniques must be observed.
The status of a cell is determined by the specific gravity of the electrolyte solution.
A specific gravity of 1.280 (obtained by hydrometer reading) indicates a fully-charged
cell. A reading of 1.250 or better is considered good. A fully-discharged cell exhibits a
specific gravity of 1.150 or less.

Battery Charger Design
The battery charger design shown in Figure 48 is based on a charging voltage of
2.4 V per cell, in accordance with most manufacturers' recommendations. The battery
charger circuit pulses the battery under charge with 14.4 V (6 cells x 2.4 V per cell) at a
rate of 120 Hz.
The design provides current limiting to protect the charger's internal components
while limiting the charging rate to prevent damaging severely discharged lead-acid
batteries. The maximum recommended charging current is normally about one-fourth the
ampere-hour rating of the battery. For example, the maximum charging current for an
average 44 ampere-hour battery is 11 A.

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If the impedance of the load requires a charging current greater than the ll-A
current limit, the circuit will go into current limiting. The amplitude of the charging
pulses is controlled to maintain a maximum peak charging current of 11 A (8 A average).
The charger circuit is composed of four basic sections:

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1. Rectifier
2. Voltage Regulator
3. Current Limiting
4. Series-Pass Element
4-113

T1

01
1N1184

+

lie
RB
200!!

1N1184
Q1
TIP642

RS

Z2

S1
-ON/OFF
SWITCH

RCL
0.227
30W

R1

TL431

R2
2.5 k!!

Vo

o -15V

120 V, 60 Hz

NOTE:

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T1 is TRIAD F-275 U 115 V Primary: 10 A/40 V Center-Tap Secondary.

Figure 48. Current-Limited and Voltage-Regulated Battery Charger

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Rectifier Section

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A full-wave rectifier configuration with a center-tapped transformer (Figure 49)
achieves maximum performance with minimum component count. The breakdown voltage
requirement for the diode is:

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4-114

000

VR
VR

> Vsecondary(pk) - VF(rectifier drop)
> 20 X 2.8 - 1 = 55 V

This design is set to current limit at 11 A, therefore, a rectifier rating of 25 A is
recommended to handle the maximum current drain plus any current surges. A pair of
IN1184 diodes was chosen (35-A/50-V rectifiers).

Vp:r.V]

.!. .Vs
2

ac

L.

VPrv
VIP="

Figure 49. Full-Wave Rectifier Section of Circuit

Voltage Regulator Section
The components which make up the voltage regulator portion of the circuit are: Zl,
QI, RI, R2 and RB as shown in Figure 50. Zl is a TL431 programmable shunt regulator
which serves as the control element, QI is the pass transistor, and RI- R2 sense the output
voltage providing feedback to Zl. RI and R2 are chosen so that their node voltage is 2.5 V
at the desired output voltage. This node voltage is applied to the TL431's error amplifier
which compares it to the internal 2.5-V reference.

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RB

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Q1

TIP642

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RCL

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VBATT

Va

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Figure SO. Voltage Regulator Section of Circuit

4-115

When the feedback voltage is less than the internal 2.5-V reference, the series
impedance (anode-to-cathode) of the TL431 increases, decreasing the shunt current
through the TL431. This increases the current available to the base of pass transistor Q1,
increasing the output voltage. When the feedback voltage is greater than the internal 2.5-V
reference, the series impedance of the TL431 decreases, increasing the shunt current
through the TL431. This decreases the current available to the base of Q1, decreasing the
output voltage. Because the feedback voltage is sensed at the output, the TL431 will
compensate for any changes in the base-emitter drop of Q1 or the voltage dropped across
RCL for various currents.

Current Limiter Section
The components which make up the current-limit portion of this circuit are: Z2, Q1,
and RCL as shown in Figure 51. The value of the current-limit setting resistor, RCL, is
chosen so that 2.5 V will be developed across it at the desired limit current. The voltage
across RCL is sensed by a TL431 programmable shunt regulator (Z2). When the output
current is less than the current limit, Vref is less than 2.5 V and Z2 is a high impedance
which does not affect the operation of Q1.
When the output current reaches maximum, Vref is 2.5 V and the impedance of Z2
decreases, decreasing the current available at the base of Q1 and controlling the maximum
output current. Under this condition, shunt regulator Z2 takes control of pass transistor Q1
and maintains a constant current, even into a short circuit.

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TlP642

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til

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TL431

t

Vref = 2.5 V

RCL

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til

Figure 51. Current Limiter Section of Circuit

4-116

Series Pass Element
The series pass element used in this configuration is a conventional Darlington
power transistor, whose control is derived from either Zl or Z2 depending on the state of
the battery being charged. See Figure 52.
The performance characteristics of Ql are important in determining the circuit
design and in the choice of the transformer to be used. This relationship is shown in the
following section on the design of the battery charger.

RB

Q1
TIP642

r-------

,I
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I

I
I

I

L ________ J
Z2

Va
R1
Z1

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Figure 52. Series Pass Element

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4-117

Design Calculations

The values of Rl and R2 set the output voltage level at 2.4 V per cell or 14.4 V for
6 cells. For optimum performance of ZI, 1 rnA should flow through the Rl and R2
combination.
R1

14.4 V
1 rnA

+ R2

=

14.4 kO

R2

;.~ =

R1

14.4 kO - 2.5 kO

2.5 kO
=

11.9 kO

For ease of final adjustment, a 20-kO potentiometer may be used for Rl.
Current limiting starts when 2.5 V is developed across RcL at the desired current
limit. For a 44-A hour battery, the maximum charge rate is 11 A.
RCL =

;·i~

= 0.227 0

The average current = 0.707 x 11 A = 7.777 A or

= 8A

The average power dissipation = IZR = 8Z x 0.227 = 14.5 W

II

After the pass transistor has been selected, its base drive resistor, RB, may be
calculated. A TIP642 meets the requirements. From the data sheet:
hFE @ 11 A = 500 (min)
VCE = 2 V
VBE
1.6 V
Pmax = 160 W @ 40°C TC
IB = 22 rnA @ ll-A peak-collector current
To calculate RB, assume a worst case or short-circuit condition where:
VI - Vref - VBE(Ql)
IB(Ql)

ISHUNT(ZZ)

= 27.28 - 2.5 - 1.6 = 1630

R
B

4-118

+

0.022

+ 0.12

RB must be small enough so that it does not limit the base current of Ql at the
desired ICHG of 8 A, but large enough to limit the current during short circuit conditions.
This value should be less than the sum of the base drive current required by Ql and
ISHUNT(max) Z2.
(VI - 14.4 V - 2.5 V - VBE(Ql»

ICHG/hFE(Ql)

RB =

27.28 - 14.4 - 2.5 - 1.6
8/500
RB =

~~186

=

548.7

n

A value of RB within this range assures sufficient drive to Ql for a charging rate of
8 A, yet allows total control of Ql by Z2 during short-circuit conditions. RB was selected

to be 200

n.

Power Dissipation and Heat Sinking
To determine the power dissipation in the IN1l83 rectifier and the TIP642
Darlington, the RMS currents and voltages must be calculated. The voltage and current
paths are shown in Figure 53.
VR(CL)

II

----+
0.235 n

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Figure 53. Voltage and Current Path
VCE(Ql)
VCE(Ql)

=
=

VI - VBATT - VRCL
10.9 V

=

27.78 - 14.4 - 2.5

=

10.88 V

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The transistor power dissipation is:
PQl
PQl
PQl

I(RMS) x VCE(RMS)
(7.78 A) (7.7 V)

=

(11 A x 0.707)(10.9 V x 0.707)

59.9 W

4-119

The rectifier power dissipation is:
P(RECT)
P(RECT)

=
=

I(RMS) X VF
10.1 W total

=

(7.78 A) (1.3 V)

If the pass transistor and rectifiers are mounted on separate heat sinks, the sinks
must be capable of dissipating the heat transferred by each device and maintain a surface
temperature which satisfies the temperature requirement for each device. Mounted
separately, the respective heat sink requirements are as follows:
PASS TRANSISTOR
ReCA:::::;

150°C - 25°C
59.9 W

ReCA :::::; 2.08°CIW

RECTIFIERS
140°C - 25°C
10.1 W

ReCA

<

ReCA

< 11.4°c/W

Depending on the mass of the heat sink and the type of cabinet, forced air cooling
may be required.

Voltage Supply Supervisor Devices
Voltage supply supervisor devices deliver a digital output signal (high or low) if
supply voltage (Vcd falls below a predefined value. The digital output signal remains in
its high or low state for a certain period of time (t delay) after VCC returns to normal.
These devices are used to sequentially initialize digital systems for proper operation at
power-on or following a VCC interruption.

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The versatility, few external components, and accurate threshold voltage of the
TL7700 series make these devices easy to use in digital systems requiring VCC line
supervision.

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General Operation

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At power-on, digital systems must normally be forced into a definite initial state. In
simple microcomputer and microprocessor applications, an RC network connected to the
RESET input pin will generally suffice. However, in more complex systems, a discrete
component design as illustrated in Figure 54 may be used.
In this circuit, after VCC reaches a specific value, defined by ZD, the input voltage
divider, and VBE, the collector of Q2 becomes high and coupling capacitor C1 provides
enough power to the RESET input pin of the digital system to execute the reset function.
The major deficiency with this type of circuit is that after power-on and the system is
operating, low VCC conditions and short drops in VCC may not be recognized. A small
decrease of VCC below the recommended supply voltage can destroy the content of the
memory and registers without activating the reset circuit. This may have catastrophic

4-120

consequences. Moreover, the circuit in Figure 54 contains an excessive number of
components, one being ZD, which has to be specially selected and is therefore relatively
expensive.
~-----------e-------e---aHa-------e~VCC

Zo

R7

12,8 V
R3~~-+

____~-e~

100 kn

RESET
MICROCOMPUTER

GNO
R2

1 kn
R1

R4

560 n

1 kn

Figure 54. Discrete Solution of a Voltage Supply Supervisor
Several features are provided in larger computers to prevent some of the problems
just mentioned. In some cases, the content of the memory is protected by a battery
back-up. However, for most applications and in small microcomputer systems, these
solutions are too expensive and generally not required. After any serious voltage drop, it is
usually sufficient to force the microcomputer into a defined initial condition. To
implement this function, while preventing the problems previously mentioned, a chip with
the following features is required:

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1. Accurate detection of a serious voltage drop

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2. Generation of a continuous reset signal while the supply voltage is not in the
operational range to prevent undefined operations.

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3. Maintenance of the reset signal for a certain time after the supply voltage has
returned to its nominal value to ensure a proper reset.

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TL77XXA Series Supervisor Chips
A functional block diagram of the chip is illustrated in Figure 55. The most critical
element of this chip is the reference voltage source, which consists of a very stable,
temperature-compensated bandgap reference. An external capacitor (typically 0.1 IJ.F)
must be connected to the Reference (REF) voltage output to reduce the influence of fast
transients in the supply voltage. The voltage at the SENSE INPUT pin is divided by
resistors Rl and R2 and compared with the reference voltage. The divider is adjusted to
achieve high accuracy at the probing operation during manufacture of the chip.

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4-121

r------------------------------l

I
SENSE
INPUT

I
I

R1

vee

RESET

(Note 11

~~OJ' RESET

I
I
I
I

I
I

I

~------~--------~----------_4~~----------

"I

__

_oGND
________
J

I
1..-----____ _

0 1IJF
.

Figure 55. TL77XXA Series Function Block Diagram

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When the sensed input voltage is lower than the threshold voltage, the thyristor is
triggered discharging the timing capacitor CT. It is also possible to ftre the thyristor with a
TTL logic level (active low) at the RESIN input. The thyristor is turned off again when the
voltage at the SENSE INPUT (or RESIN input) increases beyond the threshold, or during
short supply voltage drops when the discharge current of the capacitor becomes lower than
the hold current of the thyristor. Capacitor CT is recharged by a 100-fLA current source;
the charge time is calculated as follows:
td (internal time delay)

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en

=

CT (1.3 x 104)

A second comparator forces the output into the active state as long as the voltage at
the capacitor is lower than the reference voltage. Figure 56 is a graph plotting CT versus
tct. The SENSE INPUT pin is connected to Vee in typical applications. Figure 57 shows
the timing of the supply voltage and RESET signals.
The minimum supply voltage for which operation is guaranteed is 3 V. Between
POWER-ON (0 V) and 3 V, the state of the outputs is not defined. In practical
applications, this is not a limitation because the function of the reset inputs of the other
devices is not guaranteed at such supply voltages.
Above 3 V, capacitor CT is discharged and the outputs stay in the active state. When
the input voltage exceeds the threshold voltage, VS, the thyristor is turned off and

4-122

capacitor CT is charged. After a delay of ~, the voltage passes the trigger level of the
output comparator and the outputs become inactive. The microcomputer is then set to a
defined initial state and starts operation.

10- 1
10- 2

t

§

...

10- 3

/

'tl

10-4
10-5
10-6

/

/

0.001 0,01

/

0.1

V

v

10

100

C t (~F)->

Figure 56. Graph for Calculation of CT
SUPPLY
VOLTAGE

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OUTPUTI
UNDEFINED

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Figure 57. Timing Diagram
Operation During a Voltage Drop

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The thyristor is triggered when the supply voltage drops below the minimum
recommended value. After the supply returns to its required value, the output stays in the
active state for the duration of fd.
The delay time, ~, is determined by the requirements of tpe computer system to be
controlled. Typically, in TTL systems, a reset time of 20 to 50 ns is sufficient.

4-123

Microcomputers usually require a reset signal which lasts several machine cycles. The
duration of the reset signal is dependent on the type of microcomputer, but is typically 10
to 200 IJ.S. In most practical applications, td is determined by the characteristics of the
power supply.
During and shortly after power-on make sure voltage fluctuations do not repetitively
reset the system. Delay times of 10 to 20 ns will usually prevent this problem. Four
versions of this device are available:
Threshold
Voltage

TL7702A
TL7705A
TL7712A
TL7715A

2.53 V
4.55 V
10.8 V
13.5 V

Vee

3.0-18.0 V
5.0 V
12.0 V
15.0 V

The TL7702A may be used in applications where Vee voltages up to 18 V are used.
The required trigger level (2.5 V) may be set with a resistor divider network at the SENSE
INPUT pin. The TL7705A, TL7712A, and TL7715A have an internal resistor divider
network and operate on 5 V, 12 V, and 15 V, respectively.

TL77XXA Series Applications

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Since, for most applications, the devices are already adjusted to the appropriate
voltage levels, these chips are easy to use. Figure 58 illustrates an undervoltage protection
circuit for a TMS370 microcomputer system with a 5-V power supply. External
components are the 0 .1-IJ.F bypass capacitor at the REF terminal, which reduces transients
from the supply voltage, and the CT capacitor, which sets the time delay (ld). The
TL7705A devices do not have internal pull-up (or pull-down) resistors. An externallO-kO
pull-up resistor is connected from the RESET pin to the 5-V Vee to produce a high level.
A similar application is illustrated in Figure 59.
This circuit utilizes a TL7715 A as a protection device for a TMS 1000
microcomputer system. The CT and reference bypass capacitors are also used in this
application. Note, however, the absence of the pull-up resistor used in Figure 58. This
circuit has a required internal pull-down resistor at the INIT INPUT pin on the TMSI000
microcomputer chip.
In large systems, where several supply voltages are required (e.g., TMS8080,
TMS9900), it is necessary to supervise all supply voltages that may cause dangerous
conditions if a power failure or transient occurs. The circuit illustrated in Figure 60 uses
two TL7712A devices to check the positive and negative 12-V supplies. A TL7705A is
used to check a 5-V supply.

4-124

Vcc=+S v

Vce

Vee

10
kS1

RESETb-----4....~ RESET

RESIN

TL770SA
CT

TMS370

REF

GND
~0.1j.1F

Figure 58. TL7705A in 5-V Microcomputer Application
VSS=1SV

Vce

Vee
SENSE
RESIN

RESET 1----04 INIT

TL771SA
CT

TMS1000

REF

GND

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Figure 59. TL7715A in TMSIXXXNLP Application

The outputs of the two TL7712As are fed to the RESIN input of the TL7705A. The
output of this device, a system-reset signal, becomes active when anyone of the three
supply voltages fail. The supply voltage supervisor devices were designed to detect very
short voltage drops of 150 ns. In applications where this sensitivity is not required,
the circuit may be delayed by adding an RC network ahead of the SENSE INPUT pin
(Figure 61). To avoid influence on the threshold voltage of this input, the resistor should
be less than 22 O. The capacitor Cd is then calculated to the required delay time
(Cd = tlR).

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Another application for the TL7705A is in battery-buffered memory systems. After
a line-voltage failure, the content of the memory has to be protected against spikes on the
write line. It is usually sufficient to switch the chip-select line into the inactive state;
however, some memories also require that the write line be disabled. See Figure 62.
4-125

A switch, formed by transistor Q I and diode D I, is inserted into the chip-select line
of the memory. Under normal operation (line voltage present), the RESET output of the
TL7705A is turned off (high), transistor Q2 is turned on, and transistor QI draws its base
current through transistor Q2 and resistor RI. When the chip-select line is switched from
high to low, transistor Q I conducts and the CS input of the memory goes low. Because of
the small dc load of resistor R2, the saturation voltage of the transistor is very small
(typically 40 mY). When the chip-select line is switched high again, transistor Ql is
turned off and diode DI conducts, charging the circuit capacitance.
In case of a power failure, the TL7705A is triggered and its RESET output becomes
low, turning off transistor Q2 and the base current to transistor Ql. In this way, the CS
input of the memory is separated from the chip-select line. In some cases, it is also
recommended that memory be disabled during the system reset with the RESIN input.
This protects the memory content against spikes on the write line during this time.
+12 V
+5V
Vee

22kn

Vee
SENSE
RESIN

RESET
TL7705A

CT

SYSTEM

RESET

REF
GND

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CT

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TL7712A

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~------~-------4~-------------------------+-12V

Figure 60. Voltage Supervision of a Multiple Power Supply

4-126

--e-------------~--------~--Vee

ROO;

Vee

22 n

e----t SENSE
RESET
REF

00--"'-~ 0.1 ~F

Figure 61. Delayed Triggering
Vee--.---------------~~__,

Vee

Vee (BATTERY BUFFERED)

R2

10kn

SYSTEM
RESET-

RESIN

Vee

10 kn

SENSE

r--..........-a es

RESET D--4I>-i

MEMORY

TL7705A
eT
REF

GND

GND
~0.1IlF

10kn

CHIP SELECT

Figure 62. Circuit Diagram for Memory Protection

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uA723 Precision Voltage Regulator
The uA 723 monolithic integrated circuit voltage regulator is used extensively in
power supply designs. The device consists of a temperature-compensated reference
amplifier, an error amplifier, a lSD-rnA series-pass transistor, and current-limiting
circuitry. See Figures 63 and 64 for the functional diagram and schematic.
Additional external n-p-n or p-n-p pass elements may be used when output currents
exceeding 150 rnA are required. Provisions are made for adjustable current limiting and
remote shutdown. In addition, the device features low standby current drain, lowtemperature drift and high-ripple rejection. The uA 723 may be used with positive or
negative supplies as a series, shunt, or floating regulator.

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4·127

Figure 63. uA723 Functional Block Diagram
Vee+

500 I!

1 kl!

25 kl!

Ve

1 k!l

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OUTPUT

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:

Vz

JANON

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1--_ _ _ _ _

'--______
V(refl

Figure 64. uA723 Schematic
4-128

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"- __________ ..1

rp:,~ENT
~~~:rT

When using an external series pass device, the 3-dB bandwidth of the uA 723 must
also be taken into consideration. Adequate uA723 compensation may be provided by
connecting a 100- to 500-pF capacitor from the compensation terminal to the inverting
input. Extra capacitance may be required at both the input and output of any power supply
due to the inductive effects of long lines. Adding output capacitance provides the
additional benefit of reducing the output impedance at high frequencies.

'iYPical Applications
The required output voltage and current limits for the applications shown in
Figure 65 can be calculated from the equations given in Table 1. In all cases, the resulting
resistor values are assumed to include a potentiometer as part of the total resistance.
Table 2 affords a quick reference for many standard output voltage requirements.
Table 1, Formulas for Output Voltages
Outputs from 2 to 7 V
[Figures 65(a), (e), (f)]
V

-V
x
R2
o (ref)
Rl + R2

Outputs from 7 to 37 V
[Figures 65(b), (d), (e), (f)]
Vo

=

V(ref)

x

Rl + R2
R2

Outputs from - 6 to - 250 V
[Figure 65(c)]
Vo
R3

=

=

V(ref) x Rl + R2
2
Rl

-

R4

0.65 V

I(limit) = -R--

sc

Foldback Current Limiting
[Figure 65(f)]
(knee) =

U)

C

o
'.j:l

.

ca
G)

'tl

'iii

c

o

U

Current Limiting

I

II
cC)
'iii
G)
C

VOR3+(R3+R4)0.65 V
RSC R4

0.65 V x R3 + R4
Ios=-RSC
R4
4-129

V,

Vcc+

Vc
OUT

V(reO

Vz

REGULATED

I--~>-'IM.-""'-o OUTPUT, Va

A1

CL

A3

CS
C(ref)

I

R2

R1 • R2
A. R3 = - - - for minimum aVO.
R1+R2

Rl • R2
NOTES:

A. R3 = - - - for minimum aVO.

Rl +R2

NOTES:

B. R3 may be eliminated for minimum

B. R3 may be eliminated for minimum

component count. Use direct connection (i.e., R3 = 0).

BASE LOW-VOLTAGE REGULATOR
(VO - 2 to 7 V)

(a)

component count. Use direct connection O.e., R3 = 0),

(b) BASIC H1GH·VOLTAGE REGULATOR
(VO = 7 to 37 V)

V,

A2

Vcc+

V,

Vcc+

Vc
OUT

Vtrefj

Vz

V(ref}

Vz
CL

CL
R4 '"

R3 =
3 kU

cCD

(c)

CS

REGULATED
OUTPUT, Vo

CS

3kU

Vc
OUT

L--i>-A_SC-<> REGULATED
OUTPUT, Vo
A1
A2

A1

NEGATIVE-VOLTAGE REGULATOR

(d) POSITIVE-VOLTAGE REGULATOR
(EXTERNAL N-P-N PASS TRANSISTOR)

til

cO'
::::s

V,

(')

o

2N5001

::::s

Vcc+

til

c:CD
...
I»
....
o·::::s
til

ASC

Vz

Vz
A1

CL
CS

CS
NON·
INV

1--_.....__.....--0 ~~~~C~ T~~
A2

(EXTERNAL P-N-P PASS TRANSISTOR)

R3

CL

A1
ASC

(e) POSITIVE-VOLTAGE REGULATOR

Vec-

INV

R4

Va
lOS
I
I

'knee

A2

10

(I)

FOLDBACK CURRENT LIMITING

Figure 65. 1Ypical Applications

4-130

REGULATED
OUTPUT, Vo

V(ref)

Table 2. Resistor Values for Standard Output Voltages
OUTPUT
VOLTAGE
IV)

+5.0
+6.0
+9.0
+ 12.0
+ 15.0
-9.0
-12.0
-15.0

APPLICABLE
FIGURE (65)
SEE NOTE 1

a,
a,
b,
b,
b,
c
c
c

FIXED OUTPUT
± 5%kH
R1
R2

e, f
e, f
d, e, f
d, e, f
d, e, f

}

2.15
1.15
1.87
4.87
7.87
3.48
3.57
3.57

see
note 2

4.99
6.04
7.15
7.15
7.15
5.36
8.45
11.5

R1

ADJUSTABLE
OUTPUT
± 10% kH
P1

R2

0.75
0.5
0.75
2.0
3.3
1.2
1.2
1.2

0.5
0.5
1.0
1.0
1.0
0.5
0.5
0.5

2.2
2.7
2.7
3.0
3.0
2.0
3.3
4.3

NOTES: 1. To make the voltage adjustable, the R1 /R2 divider shown in the figures must be
replaced by the divider shown here.
R1
'IN\;

0

P1

.

T

R2
'IN\

0

2. For negative output voltages less than 9 V, Vee + and Ve must be connected
to a level large enough to allow the voltage between Vee + and Vee - to be greater
than 9 V.

General-Purpose Power Supply
The general-purpose power supply shown in Figure 66 may be used for supply
output voltages from 1 to 35 V. The line transformer should be selected to give about 1.4
times the desired output voltage from the positive side of the filter capacitor, Cl, to
ground. Rl discharges the carriers in the base-emitter junction of the TIP31 when the drive
is reduced. Its value is determined as follows:
Rl =

TIP31 voltage (at point of conduction)
leakage current of TIP31 and uA723 output

where:
TIP31 voltage at point of conduction is 0.35 V, leakage current (collector-base) of
the TIP31 plus the collector-emitter leakage of the uA723 output transistor (worst
case
200 tJ.A).

II
rn

C

o

..

"';:;

ca
Q)

"'C

"iii

c
o

(J

cC)
"iii
Q)
C

therefore:

=

Rl

0.35 V
0.0002 A

1750 G max

Rl

1.5 kG (standard value)
4-131

Potentiometer R2 sets the output voltage to the desired value by adjusting the
reference input voltage. It is connected between pin 6 (7.15-V reference) and ground. The
center arm of R2, connected to pin 5, will select any point between zero and the 7.15-V
reference.
Resistors R3 and R4 are connected in series across the supply output. The junction
of these two resistors is connected to the inverting input (pin 4) of the error amplifier
establishing an output voltage reference. This voltage reference is compared to the
selected voltage at the noninverting input to the error amplifier (pin 5) to set the level of
output voltage regulation. The values for R3 and R4 are listed in Note 1 of Figure 66. RSC
is the current limit set resistor. Its value is calculated as:
0.65 V
Rsc=--

IL

For example, if the maximum current output is to be 1 A, RSC
DIDOES
5 A -50PIV

=

0.65/1.0

0.650..

A

120~11
E

____________•

~2

uA723

3

c
CD

R2
750n

o

5

4

cO'
::s

(")

o
::s
o

TRANSFORMER

7

100 pF

FROM 10 TO 40 VOLTS AT A AND B
DEPENDING ON OUTPUT REQUIRED.

a:

..
....

CD

I»

0'

::s
o

NOTE 1: FOR 14 V TO 35 V OUTPUT. R3 - 2 k. R4 - 500 {}
FOR 1 V TO 14 V OUTPUT. R3 - 2 k. R4 - 2 k
O.S5V

CURRENT LIMIT

RSC = - - I (limit)

Figure 66. General-Purpose Power Supply

4-132

The l-kO resistor, RS, on the output is a light-load resistor designed to improve the
no-load stability of the supply. The 100-flF electrolytic capacitor improves the overall
output ripple voltage. A 100-pF capacitor from the compensation terminal (pin 13) to the
inverting input (pin 4) allows for gain variations in the uA723 error amplifiers and for
parasitic capacitances.
The output voltage and current of this supply must be restricted to the specifications
of the TIP3l series pass transistor. Since it is rated at 2 W in free air at 25°C, sufficient heat
sinking is necessary.

8-A Regulated Power Supply for Operating Mobile Equipment
It is often necessary to operate or test equipment used in automotive applications.
This supply, as shown in Figure 67, provides up to 8 A at 13.8 V. The uA723 is used as the
control element, furnishing drive current to series-pass transistors which are connected in
a Darlington configuration. Two 2N3055 n-p-n transistors are used as the pass transistors,
so proper heat sinking is necessary to dissipate the power.
This supply is powered by a transformer operating from 120 VAC on the primary and
providing approximately 20 VAC on the secondary. Four 1O-A diodes with a lOO-PIV
rating are used in a full-wave bridge rectifier. A 1O,OOO-flF/36-VDC capacitor completes
the filtering, providing 28 VDC.
The dc voltage is fed to the collectors of Darlington-connected 2N3055s. Base drive
for the pass transistors is from pin 10 of the uA723 through a 200-0 current limiting
resistor, Rl. The reference terminal (pin 6) is tied directly to the noninverting input of the
error amplifier (pin 5), providing 7.15 V for comparison. The inverting input to the error
amplifier (pin 4) is fed from the center arm of a 1O-kO potentiometer connected across the
output of the supply. This control is set for the desired output voltage of 13.8 V.
Compensation of the error amplifier is accomplished with a 500-pF capacitor connected
from pin 13 to pin 4.
The l-kO resistor on the output is a light load to provide stability when the supply
has a no load condition. The l00-flF/16-VDC electrolytic capacitor completes the filter
action and reduces the ripple voltage. The current output of the supply is sampled through
resistor RSC between the output transistor and the output terminal. The resistor value for a
1O-A maximum current is calculated from the formula:

II
rn
C

o

'';:;

...ca
Q)

"C
'Ci)
C

o

U

cC')
'Ci)
Q)

RSC

=

0.65 V
I (load max)

=

0.65

=

0.065 0

o

10

If the power supply should exceed 8 A or develop a short circuit, the uA723
regulator will bias the transistors to cutoff and the output voltage will drop to near zero
until the short circuit condition is corrected. This circuit features a no-Ioad-to-full-Ioad
(8 A) voltage regulation of no more than 0.2-VDC variation (better than 2% regulation).

4-133

DIODES 1N1200
10A-1ooPIV

120~

0.0650
}--e~~-----e-----4~-4~---+

Q1

RSC
10kO

C3

R2

R3
1,0000

13.8V

~1oojtF

.f6VDCJ..":"

~

C2
2N3055
20VAC
@10A
SECONDARY

R1

2000
10
12

2

13

3
C
S

C
L

+
uA723

REF

6
7

11

Figure 67. 8-A Regulated Power Supply
± 15 V at 1 A Regulated Power Supplies
When working with operational amplifiers, a common requirement is plus and
minus supplies in the 15-V range. A positive 15-V supply is shown in Figure 68 and a
negative 15-V supply is shown in Figure 69.

Positive Supply

cCD

en

The positive supply, shown in Figure 68, receives + 20 VDC from the rectifier/filter
section. This is applied to pins 11 and 12 of the uA723 as well as to the collector of the
2N3055 series-pass transistor. The output voltage is sampled through Rl and R2 providing
about 7 V with respect to ground at pin 4.

cS'
~

n
o

120V3111

RSC

~

15V
R3
OUTPUT
1,0000

en

c:CD

..

6

en

5

D1

ci"
~

REF

2

uA723

+

3

Rl
12kn

4

C2
100pF

R2
10kn

Figure 68. + IS-Vat I-A Regulated Power Supply

4-134

The reference terminal (pin 6) is tied directly to pin 5, the noninverting input of the
error amplifier. For fine trimming of the output voltage, a potentiometer may be installed
between RI and R2. A 100-pF capacitor from pin 13 to pin 4 furnishes gain compensation
for the amplifier.
Base drive to the 2N3055 pass transistor is furnished by pin 10 of the uA723. Since
the desired output of the supply is I A, maximum current limit is set to 1.5 A by resistor
RSC whose value is calculated as:
RSC

=

=

0.65 V
I(max limit)

0.65
1.5

=

0.433 0,

A 100-f..LF electrolytic capacitor is used for ripple voltage reduction at the output. A
I-ko' output resistor provides stability for the power supply under no-load conditions. The
2N3055 pass transistor must be mounted on an adequate heat sink since the 3.5-W, 25°C
rating of the device would be exceeded at I-A load current.

Negative Supply
The negative 15-V version of this power supply is shown in Figure 69. The supply
receives - 20 V from the rectifier/filter which is fed to the collector of the Darlington
p-n-p pass transistor, a TIPI05. A different uA 723 configuration is required when
designing a negative regulator.
-20 V

"'*
NC
RS

SI

oj (OPEN TO RESET)

1.8kn

6

9

-1~---;====~

REF

]

R3
3kn

c

o

'.,ca

uA723
R2
510

5 NON
INV

Q)

n

"C

'iii

4
R4
3kn

c
o

INV

RSC
0.39

R6
7.5 kn
R7
24kn

•.
rn

Rl

TlPl0S

__~-4__~20kn

_

(.)

10l'F

+1

cC)

n

50V

15 V
OUTPUT

'iii
Q)
C

LO;D~+

Figure 69. -15· V at l·A Regulated Power Supply

4-135

The base drive to the TIP105 is supplied through resistor R5. The base of the TIPI05
is driven from pin 9 (Vz terminal), which is the anode of a 6.2-V zener diode that connects
to the emitter of the uA 723 output control transistor.
The method for providing the positive feedback required for foldback action is
shown in Figure 69. This technique introduces positive feedback by increasing current
flow through resistors Rl and R2 under short-circuit conditions. This forward biases
the base-emitter junction of the 2N2907 sensing transistor, which reduces base drive to
the TIP105.
The fmal percentage of foldback depends on the relative contributions of the voltage
drop across R2 and Rsc to the base current of the 2N2907 sensing transistor. From the
start of base-emitter conduction of the sense transistor to the full shut-off of the TIPI05
pass transistor requires a 2-j.LA base current.
The latch condition, or 100% positive feedback, is generated by any change in the
input voltage which increases the voltage drop across R2 turning on the sense transistor
(2N2907). It can only be reset by breaking the positive feedback path with switch Sl. This
allows the series pass device to once more be driven in a normal fashion.
R3 and R4 are equal in value and divide the 7.15-V reference in half. The resulting
3.6-V reference is tied to the inverting input of the error amplifier. R6 and R7 are
connected in series across the output of the power supply. The junction of R6 and R7
furnishes 3.6 V to the noninverting input of the error amplifier. At this point, the output is
regulated at -15 V with respect to ground.
Resistors Rl and R2 are calculated as follows:

cCD

Rl(kO)

VI - *VSENSE(V)
20 - 0.5
19.5 kO

til

cO"
j

n
oj

Rl

til

R2(kO)

;

Resistor R5

c:
CD

...2)"
j

til

R5
R5

20 kO (standard value)
*VSENSE(V)

=

0.5 k or 510 0 (standard value)

(min beta Q2)
(VI - Vo - VBEQ2 - VRsC) x - - - - - - 1M (max load current)

=

(20 - 15 - 2.8 - 0.4) x 1000
1

=

1800 0

1.8 kO

*VSENSE is defined as the base to emitter voltage needed to start turn-on of the 2N2907. From the data sheet this
is about 0.5 V.
4-136

The current sense resistor

is calculated as follows:

Vo
VSENSE
IM(VI - VSENSE)

RSC
RSC

Rsc

=

15

0.5

= Ibo -

0.5)

=

0.384 {}

0.39 {}

Foldback limiting, as used in this circuit, is advantageous where excessive pass
transistor power dissipation is a problem. The TIP105 can tolerate only 2-W dissipation in
free air at 25°C ambient, so adequate heat sinking is necessary.

Overvoltage Sensing Circuits
The use of SCR crowbar overvoltage protection (OVP) circuits is a popular method
for providing protection from accidental overvoltage stress for a power supply load. The
sensing function for this type of OVP circuit can be provided by a single IC, the MC3424,
as shown in Figure 70.

___~_-_~_~_it=:=:=~------------------------~(4~)CURRENT
[~~~~}-~~
VREF = 2.6 V
SOURCE

SENSE 1 _(;::2:-,)---1i--4III----a

SENSE2~(~3)~~--+-------------+---.

.

U)

c:

L....-_ _-4.,:(~8)

(7)

VEE

'
OUTPUT

l!!

CD

(5)

REMOTE
ACTIVATE

o

"0
INDICATOR
OUTPUT

Figure 70. MC3423 Overvoltage Crowbar Sensing Circuit Block Diagram

The Crowbar Technique
One of the simplest and most effective methods of obtaining overvoltage protection
is to use a crowbar SCR placed across the equipment's dc power supply bus. As the name
implies, the SCR is used much like a crowbar would be, to short the input of the dc supply
when an overvoltage condition is detected. A typical circuit configuration is shown in
Figure 71.

'iii
c:

o

(.)

c:
'iii
CD
C

C)

4-137

FUSE
t -.......- -....- - - Vo

DC
POWER
SUPPLY

Figure 71. 'iYpicai Crowbar Circuit
The MC3423 operates from a Vee minimum of 4.5 V to a maximum of 40 V. The
input error amplifier has a 2.6-V reference between the noninverting input and VEE. The
inverting input is VsenseI (Pin 2) and is the point to which the output sense voltage is
applied. This is usually done through a resistor voltage divider which sets the trip point
(Vref) at 2.6 V. The output of the device, pin 8, then triggers the gate drive terminal of the
SCR. A basic OVP circuit is shown in Figure 72.
When Vee rises above the trip point set by Rl and R2, an internal current source
(pin 4) begins charging capacitor Cl which is also connected to Pin 3. When triggered,
pin 8 supplies gate drive through the current-limit resistor (RG) to the gate of the SCR.
The minimum value of RG is given in Figure 73.

DC INPUT

cCD

>-e-c>"\JO........-t

H~"""-""""""10,..F

+

OUTPUT

SkSl

o

VTRIP

ca':::s
o
o

•

PROGRAMMABLE DELAY

•

REMOTE ACTIVATION INPUT

o

•

DELAYED TRIGGER

:::s

a:CD

;r+

0'
:::s

o

R1

VREF(1

+;;'

":'

R1
2
MC3423
47Sl
RG

3
4

6

47kSl
SET TO TRIP
AT27V

R2'; 10 kSl for minimum drift.

'\VREF = 2.6 V
R2

SkSl

,..F

Figure 72. Overvoltage Protection Circuit

4-138

=

35r-----------------------------------~

RG(min) =0
atVCC=11V

>
I 30
w
Cl

ct

!:io

25

>

>

iII..

20

::l

en

~ 15

>

10~--~--~--~--~~--L---~--~--~

o

10

20

30

40

70

RG GATE CURRENT LIMITING RESISTOR -

80

n

Figure 73. Minimum RG vs Supply Voltage
The value of capacitor C determines the minimum duration of the overvoltage
condition necessary to trip the OVP. The value of C can be determined from Figure 74. If
the overvoltage condition disappears before C is charged, C discharges at a rate which is
10 times faster than the charging rate, and resets the timing feature until the next
overvoltage condition occurs.
10r-------------------------------------~

LL
:::\.

I

....

0.1

fI)

C

w
U

2

'

ct

5

0.01

o

ca
CD

'a

ct
ct

'iii

II..

c

U

o

I 0.001

(.)

u

c

0)
0.0001~

______

0.001

~~

0.01

______

~

________

0.1
td - DELAY TIME

~

________

~

10

'iii
CD
C

-jlS

Figure 74. Capacitance vs Minimum Overvoltage Duration

4-139

Activation Indication Output
An additional output for use as an OV indicator is provided on the MC3423. This
is an open-collector transistor which saturates when the OVP circuit is activated.
It will remain in a saturated state until the SCR crowbar pulls the supply voltage, Vee,
below 4.5 V.
This output may also be used to clock an edge-triggered flip-flop whose output
inhibits or shuts down the power supply when the OVP trips. This method of protection
reduces or eliminates the heat-sinking requirements for the crowbar SCR.

Remote Activation Input
Another feature of the MC3423 is its remote activation input, pin 5, which has an
internal pull-up current source. This input is CMOS/TTL compatible and, when held
below 0.8 V, the MC3423 operates normally. However, if it is raised above 2 V, the OVP is
activated regardless of whether an overvoltage condition is present. This feature may be
used to accomplish an orderly and sequenced shutdown of system power supplies during a
system fault condition.

cCD

U)

cO"

::s

(")

o
::s
is:

U)

.....
CD

I»

0"

::s
U)

4-140

TL 77XXA Series
Supply Voltage Supervisors

II
U)

c
o

..

'+i

cu

CI)

"0

'mc
o

o

cC)

'm

CI)

c

•

TEXAS
INSTRUMENTS

4-141

IMPORTANT NOTICE
Texas Instruments (TI) reserves the right to make changes to or
to discontinue any semiconductor product or service identified
in this publication without notice. TI advises its customers to
obtain the latest version of the relevant information to verify,
before placing orders, that the information being relied upon is
current.
TI warrants performance of its semiconductor products to current
specifications in accordance with Tl's standard warranty. Testing
and other quality control techniques are utilized to the extent TI
deems necessary to support this warranty. Unless mandated by
government requirements, specific testing of all parameters of
each device is not necessarily performed.

•

cCD

en
cQ'
:::s

n
o
:::s

en

c:
CD

;

...0'
:::s

en

4-142

TI assumes no liability for TI applications assistance, customer
product design, software performance, or infringement of patents
or services described herein. Nor does TI warrant or represent that
any license, either express or implied, is granted under any patent
right, copyright, mask work right, or other intellectual property
right of TI covering or relating to any combination, machine, or
process in which such semiconductor products or services might
be or are used .

Copyright

©

1988, Texas Instruments Incorporated

Contents
Page
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4·147
Theory of Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Typical Reset Generators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Discrete Reset Generator 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Discrete Reset Generator 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Discrete Reset Generator 3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
TL77XXA Performance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
TL77XXA Circuit Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Initialization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Low RESIN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
High RESIN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Outputs Inactive . ~ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

.
.
.
.
.
.
.
.
.
.
.

4-147
4-147
4-147
4-148
4-149
4-149
4-152
4-152
4-152
4-153
4-153

TL77XXA Electrical Specifications , , , , , , , , , , , , , , , , , , , , , , , , , , , , 4·156
Absolute Maximum Ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. . 4-156
Recommended Operating Conditions . . . . . . . . . . . . . . . . . . . . . . . . . . 4-156
Electrical Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4-157
Switching Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. 4-158

Application Examples ................................... . 4·159
Generating a Reset . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Microprocessor Applications .. . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Direct Interfacing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Indirect Interfacing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Generating Dual Reset Signals . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..
TL77XXA Supply Voltage Supervisors in Multiple Supplies . . . . . . . . . . .
Speeding Up the TL77XXA Output . . . . . . . . . . . . . . . . . . . . . . . . . . .
Slowing the SENSE IN Glitch Response . . . . . . . . . . . . . . . . . . . . . . . .
Connecting a TL77XXA as an Oscillator . . . . . . . . . . . . . . . . . . . . . . . .
Building a Watchdog Circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
The TL77XXA as a Retriggerable One-Shot Circuit . . . . . . . . . . . . . . . .
Connecting VCC of the TL77XXA to a High-Voltage Une . . . . . . . . . . . .
Monitoring AC and Unregulated DC Voltages . . . . . . . . . . . . . . . . . . . .
The TL7705A in a Battery-Buffered Memory System . . . . . . . . . . . . . . . .
Eliminating Undefmed States of TL77XXA Outputs . . . . . . . . . . . . . . . .
Sensing Different Voltage Thresholds . . . . . . . . . . . . . . . . . . . . . . . . ..
Preventing Voltage Above VCC -1 at SENSE IN of the TL77XXA .....

4-159
4-159
4-160
4-160
4-161
4-162
4-163
4-163
4-164
4-165
4-167
4-167
4-168
4-170
4-170
4-172
4-173

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4-144

Ust of IDustrations
Page

Figure
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23

Discrete Reset Generator 1 in Typical System Application ......
Discrete Reset Generator 2 in Typical System Application . . . . . .
Discrete Reset Generator 3 in Typical System Application ......
TL77XXA with Very Stable Temperature-Compensated Bandgap
Reference ....................................
Circuit for Power-Up and Detection of Short Drops . . . . . . . . ..
TL77XXA Schematic Diagram ........................
Microprocessor to TL77XXA Direct Interface ..............
Indirect Interfacing ............................. ..
TL7705A Interrupt to Microprocessor and ROM ............
TL7705A Supply Voltage Monitor Circuit .................
Circuit Modification to Shorten Transition Times . . . . . . . . . . . .
Circuit to Slow SENSE IN Glitch Response . . . . . . . . . . . . . . .
TL77XXA Oscillator Circuit .........................
TL7705A Watchdog Circuit ..........................
TL77XXA Retriggerable One-Shot Circuit ................
VCC of the TL7715A Connected to a High-Voltage Line ......
TL7702A Circuit for Monitoring Input-Transformer Output .....
TL7702A Circuit for Monitoring Unregulated DC Voltage ......
TL7705A in a Battery-Buffered Memory System ............
Elimination of Undefined States .......................
Elimination of Undefined State Using P-Channel
Depletion JFET . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
TL7702A 5% Detection Circuit .......................
Clamp Circuit for TL7702A SENSE IN ..................

. 4-148
. 4-148
. 4-149
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.
.

4-150
4-152
4-154
4-160
4-161
4-161
4-162
4-163
4-164
4-165
4-166
4-167
4-168
4-169
4-170
4-171
4-172

. 4-173
. 4-174
. 4-174

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4-146

Introduction
The TL77XXA supply voltage supetvisors are a series of monolithic integrated
circuits that monitor the power supply status in digital and computer equipment and
supply a reset signal when the supply voltage falls below the operational range. Each
TL77XXA device performs all the functions required to monitor a voltage supply and
generate complementary reset outputs whenever the voltage level being monitored falls
below a defined operational range.
The reset outputs are maintained for a certain time delay after the supply voltage
has returned to its nominal value. This allows the supply voltage to stabilize and
prevents undefined operations. The amount of delay, td, is determined by an external
timing capacitor Or in accordance with the following formula:

where:

td is in seconds
CT is in farads

Theory of Operation
This section explains why a reset function is necessary in computer applications
and how this function has been typically performed. It also explains why the TL77XXA
supply voltage supervisors are a superior alternative to typical solutions, and provides a
detailed description of TL77XXA performance.

Typical Reset Generators
A reset generator is required in most digital or computer applications where vital
data is stored in volatile memory. Most digital or computer equipment uses discrete
circuits that force the system into a defined state after power-on and when a supply
voltage drop is detected.

Discrete Reset Generator 1

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In a typical application (see Figure 1) for a digital or computer system, the reset
input is connected to an RC (resistor-capacitor) reset network.
During power-up, the RC reset network maintains the reset signal until the charge
on the capacitor reaches the threshold value. However, this network does not work well

4-147

Vee
R

DIODE

__.--.....- -...- RESET

Figure 1. Discrete Reset Generator 1 in Ty,pical
System Application

Vee

RA

01

Re
RESET
OR

RESET
ZENER
'RB

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Figure 2. Discrete Reset Generator 2 in Typical
System Application
during short voltage drops because the capacitor does not have enough time to
discharge through the diode. This circuit is also characterized by a slow rise time and an
uncertain reset time.
Discrete Reset Generator 2
Discrete reset generator 2 solves the problem of slow rise time (see Figure 2).
This circuit uses a zener diode to determine the threshold of the voltage being
monitored, (Vee). A reset signal is generated when Vee drops to a level that causes
the voltage at the junction of resistors RA and RB to fall below the zener diode
breakdown voltage.

4-148

Either a high-active RESET or a low-active RESET output can be produced,
depending on the connections to the inverting and noninverting inputs of the
operational amplifier (op-amp).
For proper operation, Vee for this circuit should never drop below the zener
diode breakdown voltage or an undefined threshold point results.

Discrete Reset Generator 3
The circuit shown in Figure 3 provides a reset signal during power-up and detects
short drops in the power supply.

Vcc
RC

01

RD

RB

RA

RE
tn

Figure 3. Discrete Reset Generator 3
in Typical System Application
This circuit generates a low-active pulse when one or both comparator outputs go
low. This occurs when Vee drops below the predefined threshold.
However, this circuit has two major disadvantages:
1.
2.

It does not generate accurate reset pulse durations.
It requires an excessive amount of components. The extra components add
to the cost of the system and occupy more board space.

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TL77XXA Performance
The TL77XXA series of supply voltage supervisors, with few external
components, solves the problems associated with typical discrete reset generators. The
TL77XXA supply voltage supervisors immediately detect low voltage conditions that

4-149

can cause a computer system to lose valuable data. Most discrete reset generators
require a severe glitch before a fault is detected. However, the TL77XXA supervisors
are sensitive to power drops of very small magnitude and duration.
In addition, fast rise and fall times are provided on the reset signal, which can be
adjusted to ensure stable operating conditions.
To eliminate the need for an external inverter, two outputs, RESET and RESET,
are provided. These outputs remain active down to supply levels of 2 V during powerdown, which would not be possible with an external inverter. Hysteresis is provided on
the SENSE IN pin to improve the device performance by preventing oscillations around
the threshold point.
Each TL77XXA circuit includes a very stable, temperature-compensated
bandgap reference (see Figure 4), trimmed to 2.53 V (typically). In all but tne TL7702A,
a precision resistor-divider network (Rl and R2) reduces the voltage at SENSE IN for
comparison with the internal reference voltage.
~-----------------------'-------------'---Vcc

RESIN-12-)----~------------~
RESET

•

SENSE 17)
IN
R1

R2
14)

~--~~----r-----------------_.--r----------e---GROUND

REF

Figure 4. TL77XXA with Very Stable
Temperature.Compensated Bandgap Reference

4·150

The typical resistance values of resistors R1 and R2 differ for the various supply
voltage supervisors in the TL77XXA series. The nominal values of R1 and R2 for each
are listed below.

TL7702A
TL7705A
TL7709A
TL7712A
TL7715A

Rl

R2

Short
7.8 kO
19.7 kO
32.7 kO
43.4 kO

Open
10 kO
10 kO
10 kO
10 kO

When the voltage being monitored at SENSE IN is within the opera!ing range,
SENSE IN voltage is greater than or equal to the threshold, the reset input (RESIN) is
high, the internal silicon-controlled rectifier (SCR) is off, and the external timing
capacitor (CT) is charged to a value above the reference voltage. Both RESET and
RESET outputs are inactive (low and high, respectively). Because both outputs are only
active in one direction. RESET must be connected to a pull-down resistor and RESET
to a pull-up resistor.
The TL77XXA outputs become active to generate a reset under various
conditions.
When the SENSE IN voltage falls 10% below its operating value, the SCR is fired,
the timing capacitor is discharged, and the outputs are forced into their active states.
With a low at the RESIN input, the SCR fires independently of the state of
SENSE IN, so that an external system can generate a reset.
The SCR is turned off again after the voltages at SENSE IN and RESIN inputs
increase above the respective thresholds.

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In the TL7702A supply voltage supervisor, SENSE IN is tied directly to the input
comparator, so that the threshold voltage can be programmed through an t:xternal
voltage divider connected to SENSE IN.
For proper operation, the recommended voltage at SENSE IN should not exceed
VCC - 1 V. Voltage in excess of 6 V at this input will damage the internal circuit. With
the exception of this feature, the performance of the TL7702A supply voltage supervisor
is identical to that of the other circuits in the TL77XXA series.

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During power-up, the outputs are undefined until the supply voltage (VCC) to the
TL77XXA reaches 3.6 V (see Figure 5). During power-down, with the voltage at
SENSE IN below the threshold, the outputs remain active until the supply voltage to the
TL77XXA falls below 2 V.

4-151

For proper operation in all TL77XXA applications, an external capacitor (O.1J,lF
minimum) must be connected from the REF pin to ground. The reference capacitor
should be connected as close as possible to the TL77XXA. Using the reference output
as a source for other circuits may result in erroneous operations.
SENSE IN
VOLTAGE
THRESHOLD
VOLTAGE

Vee'" 3.6 V
Vee'" 2 V
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RESET

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OUTPUT
UNDEFINED
OUTPUT
UNDEFINED _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _'--_ _ _•

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Figure S. Circuit for Power-Up and Detection of Short Drops
TL77XXA Circuit Operation (see Figure 6)

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During power up, before the TL77XXA attains the minimum operating supply
voltage value of 3.6 V, the bandgap reference circuit is inoperative, and both the
RESET and RESET outputs are undefined. When Vee exceeds 3.6 V, the reference
circuit is ensured to be on by transistor Q32 and the 150-kfi resistor, which form the
start-up circuit. At this point, the reference voltage (pin 1) remains fixed at 2.53 V
(typical) and is applied to the base of Q8, which is the inverting input of the comparator
Q7-Q8. The noninverting input (the base of Q7) is the divided-down SENSE IN voltage
from pin 7.

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Low RESIN
When RESIN (pin 2) is tied low, transistor Q19 is turned on and Q18 is turned
off. With Q18 off, the base of Q17 is biased to the reference voltage, turning Q17 on.
This activates the current mirror Q5-Q6, regardless ofthe state ofQ8. Also with Q17 on,
Q16 turns on causing Q12 to be shunted. This causes current mirror Qll-Q12 to be
4-' 52

inactive. Even though Q5 is on, there is no collector current flowing into Ql1.
Therefore, all the collector current of Q5 flows into the base of QlO (SCR gate). This
current flow allows both QlO and Q9 to turn on and remain on even if the gate drive is
removed.
With QI0-Q9 on, the timing capacitor cr (pin 3) and the base of Q21 (inverting
input of comparator Q21-Q22) are shorted to ground. This turns on transistor 022,
which activates current mirror Q23, Q24, Q25, Q26, and Q27. With collector current
flowing from Q26 and Q27,transistors Q28 and Q turn on, which causes the outputs
(RESET and RESET, respectively) to become active.
High RESIN
When RESIN (pin 2) is tied high, transistor Q17 draws very little current, and Q16
is off. The state of the SCR (01O-Q9) now depends only on the output of comparator
Q7-Q8, which is determined by the SENSE IN voltage.

If the SENSE IN voltage is lower than the threshold, Q7 is off, disabling current
mirror Ql, Q2, Q3, and Q4. In addition, Q8 is on, causing current mirror Q5-Q6 to be
active. With Q4 off, no current flows into Q12 and mirror Qll-Q12 is disabled.
Collector current from Q5 again flows into the SCR gate (QlO base) to turn it on. cr
discharges. This turns on 022 allowing base current to flow into 028 and Q29 and
turning the outputs on (active).
Outputs Inactive

If the voltage at SENSE IN is greater than the threshold (with RESIN still tied
high), Q7 turns on and Q8 is shut off. This activates mirror Ql, 02, Q3, and Q4 and
disables mirror Q5-Q6. With collector current flowing from Q4 into Q12, current mirror
Qll-Q12 is on. Since Q5 is off, Qll pulls current from the gate of the SCR and forces
the SCR to turn off (gate turn off).
With Q9 off, collector current from Q3 charges cr to a value above the base
voltage of Q22, after the time delay td. At this point, Q22 turns off, disabling mirror
Q23, Q24, Q25, Q26, and Q27. This removes the base drive from Q28 and Q29 and
pJact:s the outputs at their inactive (off) state.

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4-153

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IN

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150

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Figure 6. (a)

TL77XXA Schematic Diagram

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6 lal A

FIGUR::~:

B

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,

RESET
161

1

, ,

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Figure 6. (b)
TL77XXA Schematic Diagram

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Design Considerations

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TL77XXA ELECTRICAL SPECIFICATIONS
The TL77XXA supply voltage supervisors offer accurate, reliable
performance over a wide range of operating conditions. The TL77XXA
maximum allowable ratings, recommended operating conditions, and
electrical characteristics are presented in the following tables.

absolute maximum ratings over operating free-air temperature (unless
otherwise noted)
Supply voltage, Vee (see Note 1) ....................... 20 V
Input voltage range at RESIN . . . . . . . . . . . . . . . . . . .. -0.3 V to 20 V
Input voltage at SENSE: TL7702A (see Note 2) . . . . . . . .. -0.6 V to 6 V
TL7705A . . . . . . . . . . . . . . . .. -0.3 V to 10 V
TL7709A . . . . . . . . . . . . . . . .. -0.3 V to 15 V
TL7712A . . . . . . . . . . . . . . . .. -0.3 V to 20 V
TL7715A . . . . . . . . . . . . . . . .. -0.3 V to 20 V
High-level output current at RESET . . . . . . . . . . . . . . . . . . .. -30 mA
Low-level output current at RESET . . . . . . . . . . . . . . . . . . . . .. 30 mA
Operating free-air temperature range: TL77XXAI . . . . . .. -25°C to 85°C
TL77XXAe . . . . . . .. ooe to 70°C
Storage temperature range .................... -65°C to 150°C

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NOTES: 1. All voltage values are with respect to the network ground terminal.
2. For the TL7702A, the voltage applied to the SENSE terminal must never exceed Vee.

recommended operating conditions

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Low-level input voltage at RESIN, VIL

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MAX

3.6

18

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TL7705A

0

10

TL7709A

0

15

TL7712A

0

20

TL7715A

0

Low-level output current at RESET, IOL
Operating free-air temperature range, TA

V

TL7702A

High-level output current at RESET, IOH
TL77XXAI
TL77XXAe

UNIT

v

20
-16

mA

16

mA

-25

85

0

70

·e

t For proper operation of the TL7702A, the voltage applied to the SENSE terminal should not exceed
Vee - 1 V or 6 V, whichever is less.

4-156

electrical characteristics over recommended operating conditions
(unless otherwise noted)
PARAMETER

TEST CONDITIONS

VOH

High-level
output
voltage

RESET

IOH

= -16 rnA

VOL

Low-level
output
voltage

RESET

IOL

= 16 rnA

Vref

Reference voltage
TL7702A

VT

Threshold
voltage

TL7705A
SENSE TL7709A Vee = 3.6 V to 18 V,
TA = 25°e
TL7712A
TL7715A

TL7705A
VT + - VT - Hysteresis:!: SENSE TL7709A Vee = 3.6 V to 18 V,
TA = 25°e
TL7712A
TL7715A
Input
current

RESIN

UNIT

V

0.4

V
V

2.48

2.53

2.58

2.48

2.53

2.58

4.5

4.55

4.6

7.5

7.6

7.7

10.6

10.8

11

13.2

13.5

13.8

V

10

TL7702A

II

TYpt MAX

VCC- 1.5 .

= 25°e

TA

MIN

15
20

rnV

35
45

VI
VI

SENSE TL7702A VI

= 2.4 V to Vee
= 0.4 V
= Vrefto Vee -

IOH

High-level
output
current

RESET

Va

= 18 V

IOL

Low-level
output
current

RESET

Va

=0

lee

Supply
current

20
-100
1.5 V

0.5

!lA

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50

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:!: Hysteresis is the difference between the positive-going Input threshold voltage, VT +, and the
negative-going input threshold voltage, VT-.

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4-157

switching characteristics
PARAMETER
tw1 Pulse duration, SENSE

VIH+
VIL:j:

= VTmax + 300 mV,
= VTmin - 300 mV

tw2 Pulse duration at RESET and RESET

CT

= 0.1

t

VI:j:

= 5V,

Propagation delay from RESIN to
pd RESET

tr

Rise time, RESET and RESET

tf

Fall time, RESET and RESET

iJF

= 5V,
= 4.7 k!l
VI:j: = 5V,
VI:j:

MIN TYpt MAX UNIT
0.5

Ils

1.3

ms

C1

= 100 pF

5

IlS

C1

= 100 pF,

1

iJs

C1

= 100 pF,

1

IlS

R1

t All typical values are at TA = 25°C.
:j: Voltages listed are at the SENSE input.

4-158

TEST CONDITIONS

R1

= 4.7 k!l

Application Examples
This section describes several sample applications for the TL77XXA series of
supply voltage supervisors. The sample applications are as follows:

1.
2.
3.
4.
5.
6.
7.
8.
9.
10.

11.
12.
13.
14.

Generating a Reset
Generating Dual Reset Signals
TL77XXA Supply Voltage Supervisors in Multiple Supplies
Speeding Up TL77XXA Output
Slowing the SENSE IN Glitch Response
Connecting a TL77XXA as an Oscillator
Building a Watchdog Circuit
The TL77XXA as a Retriggerable One-Shot Circuit
Connecting VCC of the TL77XXA to a High Voltage Line
Monitoring AC and Unregulated DC Voltages
TL7705A in a Battery-Buffered Memory System
Eliminating Undefined States of TL77XXA Outputs
Sensing Different Voltage Thresholds
Preventing Voltage Above VCC -1 at SENSE IN of the TL77XXA

Generating a Reset
The simplest application of a TL77XXA supply voltage supervisor is its use as a
reset generator. A reset signal must be generated in microcomputer or microprocessor
systems to properly initialize the system to a known state during power-on and protect
the system memory when the system power supply is below the operational range.
The TL77XXA supply voltage supervisor can be used in microcomputer or
microprocessor equipment to generate a reset. By connecting the RESET output of the
TL77XXA to the RESET input of the microcomputer or microprocessor system, an
accurate reset pulse is generated when fault conditions occur in the power 8upplj being
monitored.
Microprocessor Applications

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The microprocessors with which the TL77XXA can interface fall into two
categories according to whether they interface directly or indirectly with the TL77XXA.
The following table lists examples of microprocessors in each category.
Direct Interfacing
MC6800
R6502
TMS7040
Intel 8085
Intel 80188
Z-80

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Indirect Interfacing
MC68000
Intel 8088
Intel 80286
TMS320

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4-159

Interfacing the TL77XXA supply voltage supervisor directly with a
microprocessor is a relatively straightforward process. Interfacing it indirectly with a
microprocessor is similar, but requires an additional consideration.

Direct Interfacing
Microprocessors in the first category, such as the MC6800, can be directly
interfaced with the TL77XXA supply voltage supervisors as shown in Figure 7. Both the
V CC and SENSE IN inputs are tied to the microprocessor system supply line, so that
the voltage being monitored at SENSE IN is the system supply voltage. The RESIN
input is also tied to the supply line.

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vcc

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IN
I.....-

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MICROPROCESSOR
EQUIPMENT
RESET

RESIN

RESET

TL71XXA
,....-- CT

REF f - - GND

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1

Figure 7. Microprocessor to TL77XXA Direct
Interface

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4-160

A small capacitor connected from the REF output to ground is required to
minimize the effects of system noise, and provide a stable reference. Another capacitor
Or determines the delay between the end of the fault condition and the return of the
'RESET output to its inactive state.
The system is forced into a defined state when a high-to-Iow transition is detected
on the RESET input of the microprocessor.

Indirect Interfacing
The microprocessors in the second category, such as the 68000, the 8088, etc.,
cannot be interfaced directly with the TL77XXA supply voltage supervisor because a
clock generator,precedes the microprocessor as shown in Figure 8.
The clock generator must generate the proper logic-reset signal (with a low
external pulse) during power-fault conditions. The high-to-low transition of the clock

generator RESET output must be synchronized to the system clock. When the clock
generator RESET input is low, the RESET output goes high after a one to two clock
cycle delay, due to the synchronization of RESET to the system clock.
r

1

Vcc

.--

SENSE
IN

-

RESIN
RESET
Tl77XXA
REF r-CT

-

r

RESET

GND
CT

T

T

Vcc

Vcc

RESET

RESET
MICROPROCESSOR

RESET
ClK
CLOCK
GENERATOR

ClK
GND

-==- 1/L F
To

1

1

Figure 8. Indirect Interfacing

Generating Dual Reset Signals
A TL77XXA supply voltage supervisor can be used in a system that requires both
low-active and high-active reset signals. Figure 9 shows a circuit that uses a TL7705A to
send interrupt signals to a microcomputer and to read-only-memory (ROM). When a

':. 10 k!l

VCC
SENSE
IN

CHIP
ENABLE
VCC
RESET

GND

GND

ROM

U)

C

o

VCC

RESET

RESET
RESIN
Tl7705A
REF r-CT

;::::::;;: CT

I

GND

~

.

'';:;

ca

f--

G)

"C

'wC
o

o

c

C)

MICROCOMPUTER

>10 k!l

'w
G)

c

0.1 /LF ;:::: ::;;:

1
Figure 9. TL7705A Interrupt to Microprocessor and ROM
4-161

power failure occurs, RESET goes high and RESET goes low. RESET resets the
microcomputer; RESET sets the ROM to a standby mode. The microcomputer output
is also used to generate a signal during a reset. This signal is sent to the ROM.

TL77XXA Supply Voltage Supervisors in Multiple Supplies
Several TL77XXA supply voltage supervisors can be used in systems that have
various supplies and that require monitoring of the supplies for proper operation.
Figure 10 shows a circuit that uses two TL7712A supply voltage supervisors and one
TL7705A to monitor 12 V, -12 V, and 5 V supplies.
The RESET outputs of both TL7712A supervisors are sent to the RESIN input of
the TL7705A, which is high during normal operation. SENSE IN of the TL7705A is tied
to the 5-V line. The RESET output of the TL7705A serves as the system interrupt
signal. When one of the three supervisors detects a fault, an interrupt signal is
. generated.
12 V

•

C

"--

RESIN

-

CT

:;;:,CT1

{C'

:;;:

0.1 pF

:::s

r

(')

VCC

o

:::s
(I)

is:
CD

"--

RESIN

0'

-

CT

:::s
(I)

, - - CT
:;;:

REF IGND

'CTJ

SYSTEM
RESET

RESET

1

:;;:

r= 0.1 pF
OV

SENSE IN
TL7712A

;

~

,

~~

DL914

i" 10 kfl

Vcc
SENSE IN
TL7705A
RESIN

RB >REF ~ 10 kll :

1

(I)

-

RESET

GND

CD

I

RA >20 kll >

Vcc
SENSE IN
TL7712A

5V

:;;:r:::: CT2

RESET
REF

-

GND

:;;:

r:: 0.1 pF
-12 V

Figure 10. TL7705A Supply Voltage Monitor Circuit

4-162

Speeding Up the TL77XXA Output
The rise and fall time of the TL77XXA output can be shortened with only a minor
modification to the circuit.
The circuit shown in Figure 11 can be used in applications where the normal
'R==E=SE=T=output pulse transition time is too slow. Connecting a transistor-inverter circuit
to the RESET output provides a 'RESET at its collector. This circuit results in a faster
response because the saturation region of 01 is avoided by clamping its base-collector
junction. Under normal operating voltage levels RESET is inactive, 01 is ensured to be
off by RB, and RESET is high. When a voltage drop occurs at SENSE IN, RESET goes
high. This turns on 01 which pulls RESET low.

01
IN914

Vee
SENSE
IN

RA

RESET I----JINI~HI____I
4,7 kf!

10 kf!

Q1

2N2222

RB

RESIN
TL77XXA

10 kf!

II

0.1 pF

U)

c
o

'::;

!

CD

Figure 11. Circuit Modification to Shorten
Transition Times

"C

';;
C

o

Slowing the SENSE IN Glitch Response

o

An RC reset network can be connected to the TL77XXA supply voltage
supervisor to slow the supervisor response to voltage drops. The TL77XXA supply
voltage supervisors are designed to detect voltage drops of less than 1 IJ,s in duration.
The circuit shown in Figure 12 can be used in applications where this fast response is not
desired, such as very noisy environments.

C

cC)
';;
CD

4-163

With an external RC reset network connected to the SENSE IN pin, the device
normal response is delayed by an amount tA, such that

where:

tA is in seconds
CA is in farads
RA is in ohms

The value of RA should be small (less than 22 0,) so that RA will not affect the
SENSE IN threshold voltage.

RA
20 n

CA
27 p.F

•

c

CD

(I)

iiJ'

Vcc
SENSE
IN

10 kn

RESET

RESIN
TL77XXA
REF
CT
0.1 p.F

Figure 12. Circuit to Slow SENSE IN Glitch
Response

:::s

(')

o:::s
(I)

is:
CD
D1
0'

...
:::s

(I)

Connecting a TL77XXA as an Oscillator
The TL77XXA can be connected so that it will perform as an oscillator. Figure 13
shows a TL77XXA.performing an oscillator function. When power is turned on, both
outputs are active (RESET low, RESET high) and capacitor C is charging. When the
voltage on C reaches the SENSE IN threshold, RESET and RESET change states. At
this time, the capacitor begins to discharge until SENSE IN voltage falls below the
threshold and the outputs become active again. The cycle is then repeated.
A sawtooth waveform is generated at the junction of RA and RB. Because the
SENSE IN voltage crosses the threshold regularly, RESET alternates between high and
low. In this configuration, RESET provides a square wave suitable for main clock
output. The duty cycle of the square wave depends upon the time that the sawtooth
wave is above and below the threshold.

4-164

The rise and fall time of the sawtooth output, as well as its general shape, is
determined by the values of capacitor C, the two resistors RA and RB, and the timing
capacitor CT.

1

I

Vcc

i= 10 k!l

RESET 1--+------....,

.------if---I SENSE
IN

,....,,....,

' - - RESIN
RESET J-.....TL77XXA
,.---t CT
REF -

lr

GND
CT

10,..F

1

-'

RB

'-'

?

,.........-.

~

1 k!l .>

::::~ 0.1 ,..F

....

RA

> 1 k!l

-:::~ C
..... ~ 10,..F

Figure 13. TL77XXA Oscillator Circuit

Building a Watchdog Circuit
A TL7702A and a TL7705A can be used in building a watchdog circuit that
monitors incoming pulses and generates a reset whenever an input pulse is absent.
Figure 14 shows a TL7702A and a TL7705A in a watchdog circuit. If the microcomputer
is operating, the watchdog input is continuously strobed by input pulses that, through C1
and D1, charge C2. To allow C2 to receive an equal charge from each input pulse, C1 is
discharged through RA between pulses.

II
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c
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..
ca
CI)

"a

In the absence of input pulses, C2 discharges through RB; when this occurs, the
voltage at the TL7702A SENSE ~N drops below its threshold and a r~set signal is
generated. This reset signal causes RESIN of the TL7705A to go low, in turn causing its
'RESET to go low, which provides a reset signal to the microprocessor or computer.
When the s~pply voltage (VCC) drops below its operational range, the TL7705A
also generates a RESET to the microcomputer.

'iii

c
o

(,)

cC)
'iii
CI)

Q

When the string of input pulses is resumed, C2 again charges to a value above the
TL7702A threshold and RESET of the TL7705A becomes inactive.
Diode D2 is connected from the TL7702A RESET output to SENSE IN to allow
C2 to be charged during power-up. For proper operation, the value for CT1 must be less
than that of Cr2.
4-165

II

SUOIJBJapISU03 uSIsaC

f"

~

Ol
Ol

VCC

10 kn

PULSE
GENERATOR

.".

02

C1
PULSE
INPUT

at.

II

S1Il.fl-

•

-

0

•

RB

RA

SENSE

'N

I RESIN

10 kll

10 kll

VCC

01

""HE 1

RESET
TL7702A
CT
REF

JSENSE'N

RESIN
RESET
TL7705A
. CT
REF

C2

~MICROP~gCESSOR
RESET
-.-

0.1 I'F

.".

Figure 14. TL770SA Watchdog Circuit

OR
COMPUTER

The TL77XXA as a Retriggerable One-Shot Circuit
Figure 15 shows the TL77XXA used as a retriggerable one-shot circuit. In this
application, cOJ!1plementary active outputs (from RESET and 'RESET) are obtained
every time the RESIN input is triggered, the trigger pulse duration plus td equals the
one shot pulse duration, and SENSE IN is tied to Vee
The outputs become active when RESIN passes from a high to a low state.
Outputs remain active if the input has a period less than the delay time, td.
In this configuration, the RESIN input can be used as a panic button to provide an
interrupt signal regardless of system condition.

10 k!l

INPUT

RESIN

RESET~--~----;-­

TL77XXA

CT

REF~---'

10 k!l

Figure 15. TL77XXA Retriggerable One-Shot
Circuit

Connecting VCC of the TL77XXA to a High-Voltage Line
The TL77XXA supply voltage supervisors can be used to monitor the output of a
regulator and to generate a reset even if the sensed voltage line drops to zero. Figure 16
shows such a circuit.
The Vee input is fed from the input side of the regulator so that it is not affected
by failures in the regulator. Because the regulator input voltage cannot be 35 V, a TlA31
programmable reference is used to drop the voltage to a level that is compatible with the
TL77XXA. Therefore, the RESET output remains active with 0 V at SENSE IN,
provided that there is enough voltage at the regulator input.

II
en

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G)

"'C

'iii

c

o

CJ

cC)
'iii
G)
C

4-167

I'A7815

Vo

OUT

IN

COM
5.1 kl!

~

;;;: r: Cj

1

Co ;;;:

"

-=-

T
~;.
TL4 31 ..,

33 kl!
'--

l"

$10 k

VCC
SENSE IN
RESIN

OUTPUT

RESET

TL7715A
r--

REF

CT

.;. 8.2 kll

GND
;;;: r:CT

1

;;;: ::::: 0.1 I'F
'-

Figure 16. Vec of the TL7715A Connected to a High-Voltage Line

Monitoring AC and Unregulated DC Voltages

c
~

en

cS·
::s

oo
::s

en

c:

..

~

m

The TL77XXA can be used in a voltage regulator system to monitor either the ac
input line to the power supply or the unregulated dc input. To avoid undefined
operations, the point monitored must be one at which a power loss can be detected as
quickly as possible.
When a TL77XXA supply voltage supervisor is used to supeIVise a volt~ge
regulator system, the regulator output should not be used as a sensing point. The
preferred points in a regulator system, because they respond more quickly to a system
power loss, are the ac input line to the power supply and the unregulated d~ input to the
regulator.

P+

o·::s
en

4-168

When the ac voltage is being monitored, the output of the input transformer can
be monitored by a TL7702A, see Figure 17. Resistors RA and RB are selected for the
desired trip point above the regulator required minimum input voltage. Diode D1 acts
as a half-wave rectifier. Capacitor C1 filters this half-wave signal so that a reset does not
occur at every half cycle. Capacitor C1 also introduces a delay between the ac power loss
and the reset signal.

When a drop in the ac line voltage is detected, the dc value of the rectified signal
drops. The values of RA and RB should be such that any change greater than the
maximum allowable drop will be detected.
REGULATOR

~-4~-'--~IN

GNO

Cj

01
914

OUT~~------'-------

RA
10 k!l
RS

10 k!l

C1

10,..F

Figure 17. TL7702A Circuit for Monitoring Input-Transformer Output
Figure 18 shows a TL7702A used to monitor the unregulated dc voltage. The
regulator remains within its specified output voltage rating as long as the input voltage
remains within its minimum and maximum limits. During a power drop, the regulator
input starts to drop before the output experiences any voltage change.
When the input voltage begins to drop, the ripple voltage also starts to drop.
Resistors RA and RB should be selected so that the threshold of the TL7702A SENSE
IN voltage is below the ripple voltage at the desired detection level (which should be
above the regulator minimum input voltage). The TL7702A therefore warns of a power
failure at the regulator input before the regulator output is significantly affected.

II)

c

o

'~

ca
...
Q)

~

'iii

c

o

(,)

cC)
'iii
Q)
C

4-169

REGULATOR

~~~II

IN

OUT

Cj

TCO

-=

RA
7.8 kO

-=

10 kO
SENSE IN
RESET
RESIN
TL7702A
REF
CT

RB
10 kO

INTERRUPT
SIGNAL

GND
0.1 I'F

CT

-=
Figure 18. TL7702A Circuit for Monitoring Unregulated DC Voltage

The TL7705A in a Battery-Buffered Memory System

o

CD
In

cCi"
:::::J

()

o

:::::J

In

.....is:
CD

I»

0"
:::::J

In

The TL7705A can be used in a circuit that protects the memory contents of a
microprocessor against spikes on the "write" line after failure of the line voltage. Figure
19 shows the TL7705A in a battery-buffered memory system. A switch consisting of
transistor Q1 and diode D1 is inserted on the memory chip select line. If SYSTEM
RESET (tied to RESIN) is high, the RESET output of the TL7705A is high, which
turns on transistor Ql.
When a power failure occurs, SYSTEM RESET goes low (triggering the
TL7705A) and RESET goes low (turning off Q1 and reverse-biasing diode D1).
Therefore, the chip select input of the memory (CS) is isolated from the chip-select line.

Eliminating Undefined States of TL77XXA Outputs
An external circuit can be connected to the TL77XXA supply voltage supervisor
in applications where the state of the TL77XXA outputs is to remain defined down to
the point at which Vee is 0 V. Figure 20 shows an external circuit that, when connected
to the TL77XXA, eliminates undefined states of the TL77XXA outputs during powerup and power-down.

4-170

VCC

.......
RB ~
10 kl!

VCC
~ 10 kl!

VCC

'--- SENSE IN
TL7705A
SYSTEM
RESET

RESIN

MEMORY

RESET

..-- CT

REF

CS

RA
10 kl!

r--

Q1

D1.~~

914

GND

GND
CT ;: ::;:
0.1

?
p.F

::;:

1
TO OTHER
CS SWITCHES

l
-=

I

CHIP
SELECT

Figure 19. TL770SA in a Battery-Buffered Memory System

f'
.....,

Design Considerations

II

BATTERY
BUFFERED
VCC

The RESET output is used to switch transistor Q1 on or off. Switching Q1 on
causes the collector (the RES output) to go high. Switching Q1 off causes the collector
to go low. When Vee is above minimu~ operational value, RESET is at a low voltage.
This condition turns on Q1 and causes RES to go high. As Vee drops, the RESET
output keeps Q1 turned off. This causes the RES output to remain active down to the
point at which Vee is 0 V.

RA
750 f!
VCC

RB

--1--1 SENSE IN

2.2 kf!

RESET
TL77XXA
CT

1-------.

REF
GND

RC
1 kf!

Figure 20. Elimination of Undefined States

o

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cE'
:::J

Figure 21 shows a circuit application that eliminates the undefined state of the
TL77XXA outputs by using a p-channel depletion JFET.

:::J

To ensure that the transistor is switched off when the supply voltage reaches a
nominal value, the gate must be more positive than the source. The circuit in Figure 21
provides the advantage of less power dissipation than the circuit in Figure 10.

c:CD

Sensing Different Voltage Thresholds

0'

The TL77XXA supply voltage supervisors are capable of detecting voltage drops
of 10%. The TL7702A can be used in a modified circuit to detect even smaller voltage
drops.

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:::J

U)

The threshold voltage at SENSE IN of the TL77XXA is designed to detect a
voltage drop of approximately 10% below the rated voltage. The TL7705A, for example,
is for use in 5 V systems and the threshold voltage at its SENSE IN is typically 4.55 V.
The TL7709A, the TL7712A, and the TL7715A have typical threshold voltages at
SENSE IN of 7.6 V, 10.8 V, and 13.5 V, respectively.

4-172

5V

~

VCC

I'A7805
REGULATOR
IN
OUT

SENSE IN

...

----;

COM
r---

Co:;;: ::::

fCi

CT:;;: ::::

<

RB
25 k!

RA
> 4.7 k!2

RESET
TL7705A
REF
CT

-

~

2N3994

f---

-

GND

;;: :::: 0.1 I'F

1.
Figure 21. Elimination of Undefined State Using P-Channel Depletion JFET
In applications where a 10% drop in voltage is harmful and therefore a drop of
5% must be detected, the programmable TL7702A with a precision voitagc divider at
SENSE IN can be used as shown in Figure 22. To calculate the exact threshold voltage
for the TL7702A, the following equation is used:

Vs

=

Rl

•.

+ R2
R2

(VT-)

fI)

c
o

where:

'~

ca

VT

=

CD

2.53 V

"C

'0
For a 5-V system with a - 5 % detection level: VS = 4.75 V, VT = 2.53 V and R2 is
selected as 10 kil. Rl, therefore, is 8.775 kil.

C

o

()

c

Preventing Voltage Above Vee - 1 at SENSE IN of the TL7702A

0)

The TL7702 must be used in a circuit that ensures that the voltage at SENSE IN
never exceeds the recommended voltage. Figure 23 shows a circuit that clamps the
voltage at SENSE IN to a value below Vee

'0
CD
C

4-173

v

CCl 5V

,>

I

> 10 kf!

R1

':-

VCC
SENSE IN

VCC
RESET

RESET

' - - - RESIN

MICROPROCESSOR

TL7702A

:.: R2
CT :;;:

r--

REF

CT
GND

f:

GND

:;: F: 0.1 ,..F

I

.l
Figure 22. TL7702A 5% Detection Circuit

Vs
VCC
4V

RA
25 kf!

RB

10 kf!

5 kf!

cCD

. - - - - t - - I SENSE IN

RESET 1-----4-

UJ

cO'
:::s

oo
:::s
UJ

a:CD

RC
10 kf!

RESIN
TL7702A
REF
GND
0.1 ,..F

....DI"'"

Cr
:::s

UJ

4-174

Figure 23. Clamp Circuit for TL7702A SENSE IN

To select the resistor values, a minimum V CC (VCCmin) and a maximum SENSE
IN voltage (VTmax) must be selected. Resistors RB and RC are chosen such that:

VTmax

=

RC
RB

+ RC

V CCmin

+ Vdiode

With this accomplished, the value for RA is calculated for the desired trip point
(VS) such that:
RC
VTnom

= RA + RB + RC

(VS)

where:
VTnom

= 2.53 V

tI)

c

o

;;

1!
G)
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';;
C

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C)

';;
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C

4·175

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en

4-176

soo-w,

SO-A, Off-the-Line,

Half-Bridge Converter,
Switching Power Supply

U)

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(1)

'C

.;
C

o

(.)

c

.;C)
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(1)

~

TEXAS
INSTRUMENTS

4-177

IMPORTANT NOTICE
Texas Instruments (TI) reserves the right to make changes to or
to discontinue any semiconductor product or service identified
in this publication without notice. TI advises its customers to
obtain the latest version of the relevant information to verify,
before placing orders, that the information being relied upon is
current.
TI warrants performance of its semiconductor products to current
specifications in accordance with TI's standard warranty. Testing
and other quality control techniques are utilized to the extent TI
deems necessary to support this warranty. Unless mandated by
government requirements, specific testing of all parameters of
each device is not necessarily performed.
TI assumes no liability for TI applications assistance, customer
product design, software performance, or infringement of patents
or services described herein. Nor does TI warrant or represent that
any license, either express or implied, is granted under any patent
right, copyright, mask work right, or other intellectual property
right of TI covering or relating to any combination, machine, or
process in which such semiconductor products or services might
be or are used.

c
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4-178

Copyright © 1989, Texas Instruments Incorporated

Contents
Title

Page

Introduction .................................................... .

4-183

Power Supply Definitions ......................................... .

4-183

Specifications .................................................... .
Block Diagram .................................................. .
Half-Bridge Converter Description .................................. .

4-183
4-184
4-184

Preliminary Calculations ......................................... .

4-186

Input Voltage Range ..............................................
Power Transformer Turns Ratio Estimate ............................
Power Transformer Current Calculations .............................
Efficiency Estimate ...............................................

.
.
.
.

4-186
4-187
4-188
4-189

Output Filter Design ............................................. .

4-189

Choke Inductance Calculations ..................................... .
Output Capacitance Calculations .................................... .

4-189
4-190

Magnetic Design ................................................ .

4-192

20-kHz Power Transformer ........................................ .
20-kHz Base-Drive Transformer .................................... .
Current Sense Inductor ............................................ .

4-192
4-193
4-196

II
U)

c
0

',tj

Local Power Supply ............................................. .

4-198

as
~

Q)

Control Circuit ................................................. .

4-199

Description .....................................................
Oscillator .......................................................
Dead-Time Generator .............................................
Error Amplifier ..................................................

.
.
.
.

4-199
4-199
4-200
4-201

Protection Networks ............................................. .

4-201

Soft-Start Capability ..............................................
Undervoltage Protection ...........................................
Overcurrent Protection ............................................
Overvoltage Protection Circuit .....................................

.
.
.
.

4-201
4-203
4-204
4-205

Base Drive Section .............................................. .

4-207

"C

'ecn
0

(J

cC)

'eQ)n
C

4-179

Contents (Continued)
Title

•

oCD
(I)

cO'
::s

n
o
::s
(I)

is:
CD

;

...0'
::s
(I)

4-180

Page

Feedback Loop Stabilization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

4-207

Km: Pulse-Width Modulator Gain. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Kc: Converter Gain. . . . . . . . . . . .. .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
G(s): Output Filter Response .......................................

4-209
4-209
4-209

Measurement Results and Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

4-213

Acknowledgment...... . .. ...... . .... ........ . .... ...... . . . . .... ..

4-221

References. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

4-221

Parts List. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

4-222

List of Illustrations
Figure

Title

Page

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27

500-W, 80-A Half-Bridge Converter Switching Power Supply
Half-Bridge Inverter Waveforms and Power Converter Section ... .
Input Filter Circuit ....................................... .
Core Dimensions ......................................... .
Coil Construction ........................................ .
Winding Sequence ........................................ .
Simplified Transformer Equivalent Circuit and Calculations ..... .
20-kHz Base-Drive Transformer Waveform ................... .
Simplified Equivalent Circuit ............................... .
TIA94 Block Diagram and Pin Assignments .................. .
Dead-Time Generator ..................................... .
Error Amplifier .......................................... .
Soft-Start Circuit ......................................... .
Undervoltage Protection Circuit ............................. .
Overcurrent Protection Circuit .............................. .
Overvoltage Protection Circuit. ............................. .
Base Driver Section for Power Converter .................... .
Linearized Loop Model ................................... .
Output Filter Model ...................................... .
Frequency Response Curves ................................ .
Error Amplifier and Loop Compensation Network ............. .
The 4O-kHz 5-V Output Filter Ripple ........................ .
The 6O-Hz Input Line Filter Ripple ......................... .
Power Transformer Primary Current ........................ .
TIPL755 Power Transistor Switching Characteristics ........... .
TIPL755 Power Transistor txo Switching Characteristics ........ .
The 500-W, 80-A, Off-the-Line, Half-Bridge Converter
Switching Power Supply ............................... .
500-W, 80-A Switching Power Supply ....................... .
Linear Post Regulators .................................... .

4-184
4-184
4-186
4-192
4-193
4-194
4-195
4-197
4-197
4-200
4-201
4-202
4-203
4-204
4-205
4-206
4-208
4-208
4-210
4-211
4-213
4-214
4-214
4-216
4-217
4-217

28
29

4-218
4-219
4-220

II
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C
0

"';:;
CIS
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CD

"'C
";

c
0

0

cC)

";

CD

C

4-181

List of Tables

•

4-182

Table

Title

Page

1
2
3

Power Transformer Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Measured Regulation Characteristics ..........................
Power Supply Efficiency and Power Factor. . . . . . . . . . . . . . . . . . . .

4-193
4-215
4-218

Introduction
The power supply was designed and built for the purposes of demonstrating and
evaluating switching power supply components under operating conditions. The primary
consideration of the mechanical design was to facilitate instrumentation, not particularly
to achieve a compact modular design.
The half-bridge circuit configuration was selected because it is one of the more
common types of converter circuits in use today. The half-bridge power converter is very
popular because of its many advantages which include: (1) voltage stress on the power
switches is no greater than the rectified power mains voltage; (2) power transformer dc
core flux can be eliminated by the use of a capacitor in series with the primary of the
power transformer; (3) reverse energy created by the transformer leakage inductance can
be commutated back to the de bus and therefore need not be absorbed by the power switches;
and (4) a simple power transformer primary is required.
Although the half-power bridge converter is very popular, it does require additional
consideration for the base drive of the power switches. These considerations include
switching speed and isolation requirements. This work details the construction of such
a base driver section that very successfully interfaces between a TIA94 control circuit
and the bases of the TIPL755 power inverter transistors.
The discussion will begin with a power supply specification and then proceed with
the detailed design considerations.

II
U)

C

The selection of the operating frequency is a compromise between physical size of
the magnetics and fIlters and loss of efficiency due to increased switching losses. The
frequency of this design was set at 20 kHz.

'';:;
CO

Power Supply Dermitions

"'ecn

Specifications
Regulated Output Power:
1) +5 volts ± 0.5% at 80 A
2) + 10 volts ±2% at 2.5 A
3) +26 volts ±2% at 2 A.
Ripple: Shall be ::5125 mV peak-to-peak on all outputs
Input Power: 120 V or 240 V, lc/>, 60 Hz
Efficiency: 65 % minimum at full load

o
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(.)

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4-183

Protection Circuits:
1) All regulated outputs shall be current limited.
2) The 5 V/SO A output shall have overvoltage protection.
Input Voltage Range:
Minimum
Nominal
Maximum

120-V ac Input

240-V ac Input

96
120
132

192
240
264

Holdup Time, th: 10 ms (time outputs remain in regulation following loss of input
power)

Block Diagram
A block diagram of the half-bridge converter switching power supply is shown as
Figure 1.

Half-Bridge Converter Description
The idealized waveforms of Figure 2 define the voltage and current characteristics
of the Power Converter Section.

en

60Hz
LOCAL
POWER
SUPPLY
XFRMR

::l
(")

RECTIFIERS

C

CD

cE"
0

TlPL755
POWER

20kHz
POWER
XFRMR

&

::l

en

......0:
CD

I»

0"
::l

en

UNDERVOLTAGE
PROTECTION
MODULATOR

Figure I" 500-W, 80-A Half-Bridge Converter Switching Power Supply

4-184

SASE CURRENT (lSi

I
I

0-

PRIMARY CURRENT (lpl

I

I

vccl 2

i_

- -

I

PRIMARY VOLTAGE (Vpl

CAPACITOR VOLTAGE (VCI

RECTIFIED SECONDARY
VOLTAGE (VFI
OUTPUT INDUCTOR
CURRENT (ILl

HALF-BRIDGE INVERTER IDEALIZED WAVEFORMS
+Vcc
D4
TJ
C7

Ll

Va
+5 V
80 A

III
t/)

C

0

'.j:i
INPUT
RECTIFIERS
AND
FIL TER

Va

BASE
DRIVER
SECTION

+10 V
2.5 A

...CO

CI)

"0

'iii
c
0

TlPL755

()
D5
Va
26V
2A
C8

C

C)

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CI)
C

HALF-BRIDGE POWER CONVERTER SECTION

Figure 2. Half-Bridge Inverter Waveforms and Power Converter Section
4-185

Preliminary Calculations
Input Voltage Range
The input rectifiers and filter capacitors are designed to operate as a standard fullwave rectifier with 240-V ac input and as a doubler with 120-V ac input (Figure 3). Switch
S2A is closed for the 120-V ac operation.

ae

Figure 3. Input Filter Circuit
Based on the specification, the theoretical minimum converter voltage, Vee, with
120-V ac input and switch S2A closed is:
Vee

c

CD

= .J2X96 Vrms x2 =

271 V

(Eq.l)

By allowing 10 V for EMI filter, surge limiting, thermistor, rectifier, and wiring
losses, the value of Vee is reduced to 261 V. This value represents Veel in Figure 3
and Equation 2. From the specification, the holdup time, th, is 10 ms. The value of minimum
filter capacitance is calculated by allowing Vee2 to be 220 V.

en

cEo
:::l
(")

o

:::l

en

c:
CD
...
I»

...o·

e

=

2PIN th
[(Vee 0 2 -(Vee2)2]

The term PIN is the input power supplied to the converter and based on a 65 %
efficiency, it is estimated to be:
5 Vx80 A

PIN

=

PIN

= 734 W

+ 10 Vx2.5 A + 26 Vx2 A
0.65

:::l

en

(Eq.2)

Therefore:
e

= 2x734 Wx lOx 1O- 3s = 744 p,F
[(261 V)2 - (220 V)2]

4-186

(Eq.3)

The capacitors Cl and C2 are connected in series for 240 Vrms operation, so the
minimum value required of each is 2 x C or "'" 1488 p.F.

Power Transformer Turns Ratio Estimate
Equation (4) is used to estimate the transformer turns ratio.
N

~[v~cl

= Np = Vp = =---:~=-:-::--=J,-:-:__
NS

Vs

Vo+Vn+VW+VREG

(Eq.4)

where
Np = number of turns on primary
NS = number of turns on secondary
Vp = transformer primary voltage [or (VCC)/(2)]
~ = duty cycle (80% assumed)
Vo = regulated output voltage
VS = transformer secondary voltage
Vn = rectifier conduction voltage
Vw = power supply wiring voltage
VREG = linear regulator voltage
Turns Ratio Calculation for + 5 V Output
Assume:
Vo = 5 V
Vn = 0.6 V
Vw = 0.1 V
VCC = 220 V
~ = 0.8

0.8[22~

_ Nl _
V] _
N - N2 - 5 V+0.6+0.1 V - 15.43 max
Turns Ratio Calculation for + 10 V Output
Assume:
Vo = 10 V
Vn = 0.7 V
Vw = 0.1 V
VREG = 5 V
VCC = 220 V
~ = 0.8
Nl
N = N3

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.....
C

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CI)

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0.8e2~

.
V]
_
10 V +0.7 V +0.1 V +5 V - 5.56 max
4-187

Turns Ratio Calculation for + 26 V Output
Assume:
Vo = 26 V
VD = 0.7 V
Vw = 0.1 V
VREG

VCC
~

=5 V

= 220 V
= 0.8

0.8e2~

_ Nl _
V]
_
N - N4 -26 V +0.7 V +0.1 V +5 V - 2.76 max
Pulse Engineering Transformer PE63203 has turns ratio Nl: N2: N3: N4 of 14:
1: 3: 6 and was selected for the application (see Figure 2).
Based on the PE63203 transformer turns ratio of (Nl)/(N2) = (14)/(1) = 14, the
converter duty cycle, ~, is calculated for various 120-V ac input voltages (assume 35-V
filter loss):

•

o

Input (V)
96
120
132

~

0.68
0.52
0.42

Power Transformer Current Calculations
The total power provided to the transformer secondaries is

(1)

UI

cS'
::J

oo
::J
UI

a:

.....
(1)

p(sec) :::::: 80 A (5 V + 0.6 V + 0.1 V)
+2 A (26 V + 0.7 V + 0.1 V + 5 V)
+2.5 A (10 V + 0.7 V + 0.1 V + 5 V)
p(sec) :::::: 559.1

w.

Assuming the inverter transformer efficiency is 95 %, the inverter input power is

C»

O·
::J

UI

4-188

p( )
559 W
P(INV) :::::: ~ .., - - .., 588 W.
0.95
0.95

Under low line conditions, the maximum duty cycle is 0.68 and the voltage applied
to the transformer primary Vp is
VCC

2

= 236 V =
2

118 V

The peak primary current is
Ip "'" P(INV) "'"
588 W
"'" 7.3 A.
Vp
0.68 X 118 V
The actual peak current is estimated to be about 10% higher or "'" 8 A due to
magnetizing current in the inverter transformer and current variations in the output filter
choke.

Efficiency Estimate
Regulated Output Power
Po
Po

= 5 V X 80 A
= 488 W

=

Po

+ 10 V X 2.5 A + 26 V X 2 A

Input Power for 65 % efficiency
PIN

= :'~5

= PIN.

46~6-: = 734 W.

A power of 588 W has already been accounted for, so 146 W remains for power
transistors, input rectifiers and wiring losses.

Output Filter Design

.1iL

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The output inductor is selected to limit the ripple current the output capacitors must
filter. Equation (5) is used to calculate the required inductance, L, once the .1iL is defined.
A .1iL is equal to 15% of the maximum output current, 10, is used in this design.

= (Va +Vo +VW+VREG) (l-i)t

en

C

"~

Choke Inductance Calculations

L

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(Eq.5)

C

All Equation (5) symbols have been previously defined in Preliminary Calculations
except t, which is the clock period of 25 p.s. i is the converter duty cycle of 0.42 , previously
calculated, for 132-V ac input voltage.

4-189

Filter Inductance Calculations for + 5 V Output
.:liL = 0.15 X 80 A = 12 A
L1 > (5 V+0.6 V+O.l V)(1-0.42)25XIO- 6 s
12 A
L1 2: 6.9 "H
Filter Inductance Calculations for + 10 V Output
.:liL = 0.15 X 2.5 A = 0.37 A
L2 >(IOV+0.7V+0.l V+5V)(1-0.42)25xlO- 6 s
0.37 A
L2 2: 619 "H
Filter Inductance Calculations for + 26 V Output
.:liL = 0.15x2 A=0.3 A
L3 > (26 V+0.7 V+O.l V+5 V)(1-0.42)25XIO- 6s
0.3 A
L3 2: 1537 "H
Pulse Engineering laminated output inductors PE50742 (8 "H), PE50731 (590 "H)
and PE50732 (2350 "H) were selected for L1, L2, and L3 respectively.

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Output Capacitance Calculations
Since the filter inductances have been chosen, the output capacitors can be selected
to meet the ripple requirements. An electrolytic capacitor can be modeled as a series
connection of an inductance, a resistance, and a capacitance. If good filtering is to be
provided, the ripple frequency must be far below those at which the series inductance
becomes important, so the two components of interest are the capacitance and the series
resistance, RC. To estimate the ESR ripple voltage, .:lVO(ESR), it is assumed that all
the ripple current in the inductor, .:liL, flows through the output capacitance.
.:lVO(ESR) = .:liL RS
where
.:lVO = peak-to-peak ripple voltage due to ESR
.:liL = peak-to-peak ripple current
RS = capacitor ESR.

4-190

(Eq.6)

The peak-to-peak ripple voltage due to the capacitance is
~VO(C)

=

~iLt

(Eq.7)

8C

where

= clock period =
Capacitance Calculation for

25 X 10 - 6s.

+ 5 V Output

The peak-to-peak output ripple must, by specification, be less than 125 mY.
The

~iL

will be limited by the 8 pH filter inductor to :510.3 A.

The maximum capacitor ESR is then
0.125 V
RS :5 10.3 A :5 0.012 {}
The Sprague 674D159H7R5JT5A, 15,OOO-/LFI7.5-V capacitor was selected because
it has a maximum ESR 0.01 {} and a maximum ripple current 12.3 A. The ripple due
to capacitance is

~V
O(C) =

10.3 Ax25 X 1O- 6s
2 V
8 X 15 X 10 - 3F
... m

which is negligible.
Capacitance Calculation for

+ 10

V Output

0.125 V
RS :5 0.37 A :5 0.337 {}

U)

..
c::

o

"

C < 0.37 Ax25x 10- 6 < 74 F
0.125 V
/L.
The Sprague 672D687H020ET5C, 680-/LF/20-V capacitor was selected because it
has a maximum ESR 0.08 {} and a maximum ripple current 2.5 A.
Capacitance Calculation for

+ 26

V Output

0.125 V
RS :5 0.3 A :5 0.416 {}

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C

C < 0.3 Ax25x 10- 6 < 60 F
0.125 V
/L
The Sprague 672D337H04OET5C, 330-/LF/40-V capacitor was selected because it
has a maximum ESR 0.2 {} and a maximum ripple current 2 A.
4-191

Magnetic Design
20-kHz Power Transformer
A ferrite "E" core with a rectangular center leg is used for the power transformer.
Dimensions are shown in Figure 4. This is generally the most economical shape and is
easy to wind and insulate. The core has a throughput power rating of 620 W for a 40 °C
temperature rise.

1.

4f----- 2.160

T
1
2.170

---·.1 --1
-

r--

-

---.

I+-

1-----

-

~

0.812

r

1.480

1 -----

+-

0.42 0 ....

--..

0.660

+-

Figure 4. Core Dimensions
The coil is designed with 8-mm creepage/clearance and three layers ofO.l-mm thick
insulation between the primary and secondaries to comply with the most common
international safety requirements for construction. The 5-V winding is wound with copper
foil for low ac winding resistance at 20 kHz. To further reduce ac resistance and to minimize
leakage inductance of the 5-V output, windings are arranged as shown in Figure 5. Low
leakage inductance is illustrated by the low voltage overshoot at the start of "dead-time"
in Figure 26. Data for this application are tabulated in Table 1.

4-192

Table 1. Power Transformer Data
1/2

5V

10 V

26 V

Primary

Secondary

Secondary

Secondary

28

2-0-2

6-0-6

12-0-12

Conductor Size

19 AWG

2X.01 Cu

22 AWG

22 AWG

Pk Term, Voltage

100

7.96

23.57

47.1

-

5.66

16.97

33.9

Turns

DC Term, Voltage

@

DC Current, A
RMS Wdg Current

@

Throughput Power,

W

5.72
562.2

80

2.5

2.0

52.5

1.64

1.31

452

42.4

67.8

DC Resistance,

0.079

0.0007

0.095

0.185

AC Resistance,

0.130

0.0007

0.100

0.194

2.130

1.93

0.27

0.33

@

Copper Loss, W
Total Cu Loss: 4.66

CD

Core Loss: 1 .04

Total Loss: 5.7 W

@

Primary halves parallel connected.

@

Nominal primary leakage inductance: 3 ",H (5-V Secondary shorted)

@
@
@

Primary throughput power = E (dc Term Voltage) x (dc Current)
Transformer efficiency = 99% at 562 W throughput power.
At 72% duty cycle.

10 V SECONDARY

I I 26 V SECONDARY

1/2 PRIMARY

en

5 V SECONDARY
1/2 PRIMARY

c

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'.jj
as
~

Q)

"'0

COIL FORM

=----.J'

Figure 50 Coil Construction

20-kHz Base-Drive Transformer
The design objectives for the base-drive transformers were to provide:
1) Base current of 1.0 A minimum
2) Fast base-current rise time
3) Simple means to clamp dead-time voltage
4) Balanced secondary waveforms
5) Insulation for off-line operation.

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cC)
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o

4-193

To meet the first objective, ferrite E cores sized to limit temperature rise to 40°C
were selected. E cores are easier to insulate reliably for off-line operation than toroids
or more complex shapes. Units are fully encapsulated for improved insulation and thermal
characteristics. The transformers will withstand 1500 Vrms dielectric strength test between
base windings. Temperature rise is under 40°C at 1.5 A base current.
To obtain fast base-current rise time, minimum turns limited by core saturation are
used and the base windings are tightly coupled to the primary. The clamp winding is also
·tightly coupled to the primary to assure effective core shorting during the dead time using
the circuitry described in the Preliminary Calculations Section.
The winding sequence of Figure 6 is used to obtain coupling requirements. Base
windings are multifilar wound for balanced drive.
BASE WINDINGS
PRIMARY
CLAMP

COIL FORMJ

Figure 6. Winding Sequence
A simplified equivalent is shown in circuit Figure 7 and calculations are discussed.

cCD
(I)

cO'
j

oo
j

(I)

c:CD

...0'0;

From catalog data for Pulse Engineering PE62129, the internal secondary resistance
(RsD is 0.14 0, yielding a typical internal voltage drop of 0.14 VIA amp ofload current.
Since this is usually negligible, the following are reasonable approximations:
Secondary terminal voltage (V s):
Vs =:Vin/n

(Eq.8)

Peak secondary current (Is):
I

- Vs-VBE
Rb

s -

(Eq.9)

j

(I)

Note: Is=IB1
Solving Eq. 9 for Rb:
Rb

4-194

= V.....s --:-V~B=E
Is
_

(Eq.lO)

IDEAL
n : 1

r----'

Ip--'
Lp

I

I

I
I
I
I

I
I

I

I

..r.

I

- (Rs + Rser + Rt)
n2

If 1m < 

e>
N

}
10l's/DIV

Figure 8, 20-kHz Base-Drive Transformer Waveform

lin-+

,

R'

e

R~er

I'

,

1m

t

~

Lp

I DEAL
1:n
--,

i-

~ i~
....
I

R,

Rser

V

I

0

~Rt
I

---'

R't

Im~--

voJ:i~r~;;"

en
r:::

o
'';:;
ca
~

Q)
Rp

= PRIMARY WINDING

RESISTANCE

R, = SECONDARY WINDING RESISTANCE
Rser

= EXTERNAL RESISTANCE
TERMINATING RESISTOR

Rt

= TERMINATING

RESISTOR

IN SERIES WITH

Lp

= PRIMARY

"C
INDUCTANCE

n = PRIMARY-TO-SECONDARY TURNS RATIO OR
SECONDARY TURNS FOR ONE TURN PRIMARY
lin = INPUT CURRENT
1m = MAGNETIZING CURRENT
I, = SECONDARY CURRENT

NOTE: PRIMES FOR SECONDARY VALUES REFERRED TO PRIMARY.

'in
r:::

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'in
Q)
C

Figure 9, Simplified Equivalent Circuit
If the primary is one turn and the terminating resistor ohmic value equals turns,
output voltage is 1 VIA of output current (scale factor). The scale factor is proportional
to the terminating resistor and independent of winding and other series resistances.

4-197

For minimum output voltage droop, magnetizing current must be low. For rectangular
pulses, magnetizing current is approximately:
1m

== VP ton == lin (Rs + Rser + Rt) ton
Lp
n2Lp

This neglects voltage droop.
The PE51719 has 100 turns on each side of the center tap. Resistance of each side
is 2 O. A one-turn primary has 2-ItH inductance and will support a 4 V-itS unipolar, or an
8 V -itS bipolar waveform.
For this application, peak input current is 8 A and maximum ton is 18 itS. A diode
is in series with the 100-0 terminating resistor R32. Assuming 0.6-V drop, effective diode
resistance is approximately 0.6 n/lin = 0.6(100)8 =7.5 O. Shunting ofR31, R30, and Q6
is negligible. Magnetizing current is approximately:

I
m

== 8(2+7.5+ 100)(18 x 10- 6) == 0.79 A

1002

(2x 10-6)

This results in output voltage droop of about 10 %. Vpion is 1. 75 V-itS which is well within
the 8 V -itS rating. Droop and scale factor could be reduced by using a smaller terminating
resistor.

Local Power Supply

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:::s
en

a:CD
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:::s
en

The function of the local (auxilliary) power supply is to provide the TIA94 control
circuit and the base drive section with a source of regulated power. The anticipated power
requirement for the TIA94 is 100 rnA at 15 V and the anticipated base drive section power
requirement is 500 rnA at 15 V. The estimated total regulated power is therefore 600 rnA
at 15 V. A 60-Hz transformer, rectifier, linear regulator system was selected.
The secondary voltage rating, VS, of the transformer was then calculated based on
(Eq.13).
Vs

= VD+~VC+VREG+VO

where
VREG = linear regulator ~ Voltage
3 V
VD = rectifier voltage = 1 V
~V C = ftlter capacitor voltage swing = 4 V
Vo = regulated output voltage = 15 V
Vs = 1 V+4 V+3 V+15 V

~
4-198

(Eq.13)

~

=

16.3 Vrms

The nearest commercial transformer secondary voltage value to 16.3 V is probably
24 V, therefore the wattage rating of the 6O-Hz transformer should be 14.4 W, i.e.,
VA = (24 V) (0.6 A) = 14.4 W.
The input filter capacitor, CI0, minimum value was determined to be 846 p.F based
on (Eq.14). A l000-p.F/50-V capacitor was selected.
CI0

(Eq.14)

where
PIN
th
VCCI
VCC2

= 0.6 Ax18 V = 10.8 W
= hold-up time = 10 X 10 - 3s
= .j2x24 V = 33.9 V
=.j2 X 24 V - 4 V = 29.9 V

Control Circuit
Description
The TlA94 integrated circuit (Figure 10) was selected for the control of the power
supply over a discrete design to take advantage of the lower component count with the
TlA94.
In addition to the basic functions of oscillator, pulse-width modulator, and error
amplifier, the circuit also provides independent dead-time control and overcurrent detection.
The TlA94 supply voltage can be varied in the range 7 V - 40 V. The reference
voltage developed on the integrated circuit is 5 V ± 5 % and is set by a bandgap reference
giving excellent immunity to supply and temperature variation.
The TlA94 also has an output control logic feature which allows single-ended (90 %
max duty cycle) or push-pull operation (45% max duty cycle at each output).

Oscillator
The TlA94 , s oscillator frequency is programmed with an external capacitor and an
external resistor, pins 5 and 6. The oscillator clock frequency, fop, must be set at 40 kHz
for the converter to operate at the specified 20 kHz.

II
rn

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4-199

f.
_
1
op - 2 RT CT
Choose CT
RT

= 0.001

(Eq.15)

p,F and calculate RT.

1
= ----;:------:;:
3
6

2x20x 10 x 0.001 x 10-

= 25 leO
Dead-Time Generator
The duty cycle must not be limited to less than 68 % or the supply may not be able
to output rated voltage at low input line voltage. It is also important to limit the maximum
duty cycle to 86% or less to allow the TIPL755 power switches 3.5 p,s of storage time.
An 80% duty cycle design was selected. By choosing R23 = 1 kG, R22 was calculated
to be 9 kG.
t

1d

3V
=----.....,..---==--_=r
0.1

(Eq.16)

V+5 V[iu:;~2]

where
t = 25 p,s = clock period
p,s = dead time

1d = 5
R23

= 1 kG

The dead-time generator circuit is shown in Figure 11.

c

CD

CIl

cS'
~

0
0

~

CIl

a:CD

..

m
....

0'
~

CIl

PIN NO.
1.
2.
3.
4.
5.
6.

1.

8.
9.
10.

11.
12.
13.
14.
15.
16.

FUNCTION
ERROR AMP. 1, NONINVERTING INPUT
ERROR AMP. 1, INVERTING INPUT
COMPENSATION INPUT
DEAD TIME CONTROL INPUT
OSCILLATOR TIMING CAPACITOR
OSCILLATOR TIMING RESISTOR
GROUND
DRIVE TRANSISTOR 1, COLLECTOR
DRIVE TRANSISTOR 1, EMITTER
DRIVE TRANSISTOR 2, EMITTER
DRIVE TRANSISTOR 2, COLLECTOR
INPUT SUPPLY
OUTPUT MODE CONTROL
STABILIZED REFERENCE VOLTAGE
ERROR AMP 2, INVERTING INPUT
ERROR AMP 2, NONINVERTING INPUT

Figure 10. TIA94 Block Diagram and Pin Assignments
4-200

r-------------

OSCILLATOR RAMP

OUTPUT POWER SWITCHES

1

T

~

~

1
3 V

-~td~ ~ "f
~ 01 U 03 L
I

Figure 11o Dead-Time Generator

Error Amplifier
The error amplifier (Figure 12) compares a sample of + 5-V output to a voltage
reference and adjusts the pulse-width modulator to maintain the proper output. It also
contains the compensation input for the network which shapes the frequency response of
the regulator so that it is stable over the range of the line and load variations.

Protection Networks

II
en

c
o
0,i:

.

(U

CD

Soft-Start Circuitry
In order to reduce the stress on the TIPL755 power switches at power supply startup,
it is necessary to reduce the startup surge which is otherwise seen as the output filter
capacitors charge.
By applying a negative slope waveform to pin 4 of the TIA94's dead-time comparator,
this "soft-start" characteristic is achieved, allowing the pulse width at the output stage
to increase slowly (Figure 13).

."

°iii

c
o

(.)

c0)
°iii
CD
C

4-201

The soft-start timing capacitor is selected to provide a time constant, tconst, which
is approximately one-third the desired output rise time, tr, of 50 ms.
t -onst
"C

= 1/3 t = (C 15) (R22 x R23)
[R22 + R23]

r

or
C15

= [1/3 tr][:;;~:;~]

(Eq.17)

C15 is calculated to be 18 p,F
where
tr = 50 ms
R22 =9kO
R23 = 1 kO

TO OUTPUT. +5 V = Va

R17

R13

R14

R18

R15

COMPENSATION
NETWORK

~ ~(

V = V
a
R

R13 +-2R14)
R18
) (1 +
R17 + R18

R14
R15+ -

2
WHERE V R =5V
R14 POTENTIOMETER SET MID VALUE

Figure 12. Error Amplifier
4·202

r----------I
I
I +5 V = V R

/1/1

OSCILLATOR
RAMP

j ,-_--.
OSC

"----( 7 }-+-..,
TL494

I

PIN 4 VOLTAGE
/

OSCILLATOR RAMP

VOLTAGE, PIN 5

->6.444<1

II
U)

C

o

..

DRIVE
SIGNAL

"';:

ca

Q)

"'0

Figure 13" Soft-Start Circuit

"in

c
o

Undervoltage Protection

(.)

In the low supply condition, (VCC :s 7 V), correct operation of the control logic
cannot be guaranteed even when pin 13 is correctly wired to the regulated voltage source
and the pUlse-steering flip-flop is enabled. Under this low voltage condition, simultaneous
conduction of both outputs may occur and, of course, TIPL755 immediate destruction
is certain to follow.

c

en
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Q)
C

The circuit shown in Figure 14 is designed to cause Q5 to be turned on when
VCC :s 9.4 V. This Q5 on condition causes the reference voltage to be applied to pin 4
of dead-time comparator which causes both outputs to be disabled. (The TL494A has a
monolithic undervoltage protection network and its use eliminates the Figure 14 circuit.)
4-203

TO AUX 60 Hz SUPPLY

r----J---~I-vcc

.

= INPUT SUPPLY

OUTPUT MODE CONTROL
R11

R12

TL494

Figure 14. Undervoltage Protection Circuit
The Rll, R12 voltage divider was designed according to Equation 18.
(Eq.18)

c

"en
iiJ'
:::J

oo
:::J

where
VCC(min)
VR
VBE(Q5)
R12

= 9.4 V
= 5 V = reference voltage
= 0.7 V (assumed)
= 4.7 kO

en

Overcurrent Protection

I»

A current sense inductor, T4, is placed in the primary side of the power transformer,
T3, so that it will be responsive to core saturation as well as provide overcurrent limiting
by use of the TlA94 dead-time control input (Figure 15).

"......

is:
0'
:::J

en

The load fault primary current, Ip , chosen for the design is 8 A based on the peak
primary current calculation of the Preliminary Calculations Section.
Pulse Engineering current sense inductor PE51719, when connected to a 100-0
terminating resistance, is designed to generate an output voltage, V0, of 1 V/ A. Therefore,
at the 8-A fault condition, an output voltage, Yo, of approximately 8 V will be produced.
At V0 = 8 V, the voltage divider network consisting of R30 and R31 is designed to tum

4-204

I

I • • POWER TRANSFORMER
PRIMARY CURRENT

R31

1

R32

R30

va

CONTROL VOLTAGE, Vo~
PIN

0

OSC

RAMP~

~,~

,1
,"

,,"

,,'

---

I

,"

I

I.,,'

......---OEAO-TIME VOLTAGE, PIN8

~

"

I

I

I

I

J

',"

O~~--------~----------~----------~----------~----------~
POWER
TRANSISTORS
O~~________J _____________-L__~______________________________

II)

C

o

O-r----------__ ________J -_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

".j:i

Figure 15. Overcurrent Protection Circuit

"C

~

L_J_

e
Q)

"iii

on Q6 which turns on Q5. The turned-on Q5 applies the +5 V reference voltage to pin 4
of the dead-time comparator. The reference voltage on pin 4 causes the output drive to
be terminated and also toggles the pulse-steering flip-flop to the other output drive prior
to the completion of the oscillator period. However, both output drives are inhibited because
CIS is discharged through the turned-on Q5 and this action causes a voltage to remain
on pin 4 until C15 can charge through R23 according to the normal "soft-start" mode
described in this section.

c

o

(J

c

C)

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Q)

o

Overvoltage Protection Circuit
The MC3423 is used to sense an overvoltage condition at the 5-V/80-A output and
will trigger the crowbar SCR2. The trip voltage is programmed at 5.3 V, reference
Equation 15. See Figure 16.
4-205

+5V

TO AUX POWER SUPPL Y

C19
R34

R33

Figure 16. Overvoltage Protection Circuit
Vtrip

cCD
o

cS·
::s
("')
Q

::s
o

c:CD
...I»

...o·
::s
o

-= VREF r, +

e

R36]
R37

(Eq.19)

where
R36
R37
VREF

= 4.7 kG
= 5.1 kG
= 2.75 V max

The MC3423 is also programmed for a 40-JLs minimum duration of overvoltage
condition, td, before triggering, thus supplying noise immunity, reference Equation 20.

td -= [1.2 x 104]C20

(Eq.20)

where
C20

td

= 0.0033 JLF

= JLS duration overvoltage

Any overvoltage condition that causes crowbar SCR2 to fire also causes a signal
to be concurrently sent to SCRI and it is also caused to fire. The turned-on SCRI provides
base current to Q5. Q5 turns on and provides -= 4 V to the TIA94 dead-time control,
which shuts down the converter and thereby prevents the crowbar SCR from destruction.
To reset, the power supply must be turned off for at least 15 seconds.
4-206

Base Driver Section
The base driver section is designed to provide an electrical isolation interface between
the TIA94 control circuit and the TIPL755 power transistor switches. This driver section
also provides current outputs of approximately 1 A to the bases of the power switches.
It is necessary to provide about I-A base drive in order for the TIPL755s to switch as
much as an 8-A transformer primary current.
To provide the required isolation, Pulse Engineering's 20-kHz Base-Drive
Transformer PE62129, with two secondaries, was selected. This transformer is designed
with a 15: 15:5 turns ratio and 15-V input, 5-V/1.5-A output. An important feature of this
base drive transformer is that a clamp winding is provided to eliminate switching transients
during the turnoff or converter "dead-time" interval. The clamp winding is shorted to
ground during the converter "dead-time" by means of a 112 SN75413 OR driver that
has its two inputs connected to the respective TIA94 outputs. The TIA94 is operating
in a push-pull mode so that one output is high while the other is low, except during the
"dead-time" interval when both emitter follower outputs are low, e.g.:
TIA94 Outputs
(SN75413 Inputs)
SN75413
Output A
OutputB
Output
H
L
H
("Dead-Time")
L
L
L
L
H
H
("Dead-Time")
L
L
L

II

When driving a I-A load, the PE62129 primary current is estimated to be = 0.44 A
(see the Magnetic Design Section). The maximum current of the TIA94 output transistors
is only 250 rnA, therefore a predriver stage was needed. To meet this requirement, the
ULN2066, which has a 1.5-A current rating, was selected to drive the transformer primary.
Because the transformer primary is connected in a push-pull configuration operating from
+ 15 V, the ULN2066 must switch 30 V or double the + 15-V supply. The ULN2066
has a 50-V rating; therefore, an approximate 20-V safety margin exists. To provide a low
impedance off-drive for a reduction of storage time and fall time of the power switches,
the circuit shown in Figure 17 was incorporated into the design to provide approximately
1.5-A IB2 reverse-bias current.

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II)

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c

o

o

C

t»

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II)
C

Feedback Loop Stabilization
Many papers have been written concerning the mathematical analysis of feedback
loop phase-gain calculations and equipment measurement techniques. Some of these papers
are listed in the references. The error amplifier and loop compensation network design
methods used in this report are based on techniques presented in the Texas Instruments
Incorporated, Switching Power Supply Design Student Guide, Chicago Regional Technology
Center.

4-207

15V
TL494

5V

1/2 ULN2066

TlPL755

50

510

TIP41

68 !l

1N4001

510

~.

PWR DEV:CE

NOTE,
20 kHz BASE-DRIVE TRANSFORMER
PULSE ENGINEERING
PE 62129/2 SECONDARIES

Figure 17. Base Driver Section for Power Converter
This power supply system is described by a total linearized single-loop model made
up of five stages, as shown in Figure 18.

c

(1)

en
cEo
~

n
o
~
en

c:

.

Km
MODULATOR
GAIN

f-+

Kc
CONVERTER
GAIN

r---

G(s)
OUTPUT
FILTER

4-

Ol
SAMPLE
NETWORK

4f'
H(s)
ERROR AMP

+
COMPENSATION
NETWORK

(1)

C»

r+

0"
~

en

4-208

Va

-+

Figure 18. Linearized Loop Model

~

Km: Pulse-Width Modulator Gain
The pulse-width modulator converts an error voltage into a drive pulse width. Its
gain is the change in pulse width resulting from a change in error voltage. The modulator
used in the TlA94 is a comparator with a triangular wave applied to one input and the
error signal applied to the other; drive command duration is equal to the time the sawtooth
exceeds the error voltage. The drive pulse width changes from maximum to minimum
as the error signal changes from the minimum ramp value to its maximum.
Therefore

Km

=

ton(max) - ton(min)
Vramp(min) - Vramp(max)

where
ton(max) = maximum drive period
ton(min) = minimum period = 0
Vramp(min) "" 0 V
Vramp(max) 3 V

= t = 25 p,s

=

Km

= 25

p.s
-3 V

= _ 8.34 p.slV

Kc: Converter Gain
The gain of the converter is the change in output voltage relative to a change in
drive pulsewidth.
U)

I:

Vee -VD
Kc

= AVo

Aton

where
Vee
n
VD
t
Kc

o

..

2n

'~

C'CI

t

CD

"C

= converter

input voltage
= turns ratio = 14
= rectifier drop "'" 1 V
= clock period = 25 p.s
290 V -1 V

'U;

=

290 V

2x 14

= - - - - = 0.37 V/p.s.

I:

o

(J

I:

C)

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CD

C

25 p,s

G(s): Output Filter Response
The model shown in Figure 19 is used to predict the low-pass filter response and
filter break frequency, ff.

4-209

L

c

Figure 19. Output Filter Model
where
L
C
RS

= output choke inductance =- 8 Jili
= output capacitance =- 15,000 p.P

RL

= load resistance

= wiring and choke resistance =- 0.01
Rc = output capacitor ESR =- 0.006 (}

(}

=- 0.0625 (} minimum

without going through the mathematics,
G(s)

= Vo (s)
Vi (s)

= __~~_R~C~R=L~(s_+_I_/Rc~C~)/_L_(~R~L.+_Rc~)~_____
s2+sC
1
+Rs+ RL Rc ] + RS+RL
~RL + Rc)C L L(RL + Rc~ L(RL + Rc)C
The open-loop response of the regulator is

Vo~s) = KrnxKcxG(s)
Vm

The filter break frequency is

1

ff

= -:---r.:==:===:::z:=:===::::::=:::::===::::;::::==z=2 'II".J8XlO 6Hx15,OOOxl0 6p

A compensation network was designed to provide a zero, fzl near the filter break
frequency, ff, and a pole at a much higher frequency, fp2, where the response has already
gone through unity. Since very high gains at low frequencies are required for dc accuracy,

4-210

an additional pole, fpI, and a zero, fz2, are required. The pole, fpI, is positioned at 50 Hz
to reduce the gain sufficiently for the regulator response to go through unity gain, fr,
beyond the ftlter breakpoint but well below the regulator operating frequency,
fo = 20 kHz. The zero, fz2, is positioned at the ftlter break frequency to cancel the slope
of the response due to the ftlter low frequency pole. The net effect is an open-loop response
with a slope of approximately - 20 dB/decade through unity gain, see Figure 20.

..... r

ERROR AMP RESPONSE

... /

Ip2 -....
..............

Ip3~

.p-._._._._.-

c(

Jlc

Ipl""""\ 1 1
2"= ~

'-'-'-0.,.

",

COMPENSATION~
NETWORK
RESPONSE

I

""'" / /
~REGULATOR OPEN LOOP RESPONSE,
/..........,.,.y
- 20 dB/DECADE
. ~

\

'"

"

/
"

/

I
...... J
Z1 AND Z2--+""O

/1 "-

'"
.............
"'
IT OR UNITY GAIN AT 2 kHz

II)

C

o

'~
FILTER RESPONSE.-"'"
-40 dB/DECADE

~

CD

"C

I-Frequency 1kHz)

Figure 20. Frequency Response Curves

'in

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o

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C

tn

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C

4-211

The following equations and chosen values were used to calculate the component
values for the compensation network, see Figure 21.
1
ff =fzl = - - 2 7r.JLC

fr = 2000 Hz
f za

=

R13
(R13 +RI5) KmxKc

~---'----

27r R19 C17
1

= 50 Hz = -2-7r-(R2-0-+-R-I-9)-C-I-7

f,1=50Hz=
I
P
2 7r[(RI31 R15) + R16] Cl3

•

fzl

= 460 Hz = - -I- -

f. 2

= 460 Hz

Z

27r Rl6 Cl3

I
= -----27r (R13 + R21) C16

f, 2 = 8000Hz
p'

27r [(R13IRI5IRI6)+R21] C16

1
f, 3 = 40 000 Hz = - - - - . . . ; ; ; , . . - - - p,
27r (RI3~RI511R21 ~RI6) C14
where
L
C
Km
Kc
C17
C13

4-212

1

= ----------

=8JLH
= 15,000 JLF
= 8.34 JLsIV
= 0.37 V/JLs
= 0.02 JLF
= 0.47 JLF

r-------

TO Va = +5 V

I

I
R13

TO

R14~-""'-""'''''''

C14

I
I
I
I
I

I
I

R17

ERROR

R19
R20

R18

II
(I)

Figure 21, Error Amplifier and Loop Compensation Network

Measurement Results and Conclusions

C

o
+=
~

Q)

"C

Measurements of load and line regulation were made at various input voltages while
load conditions were changed from 5 A to 80 A at each input voltage. The overall regulation
of each of the lO-V and 26-V outputs, which are regulated by linear regulators, was
measured as better than 1 %. The overall regulation of the 5-V, 80-A output, which is
regulated by the TlA94 master control, was measured as 0%. The test results are shown
in Table 2.

';
C

o

o

c0)
';
Q)

C

The 40-kHz ripple of the 5-V output was measured as approximately 60 mV peakto-peak (Figure 22). The ripple across the 60-Hz input line voltage capacitors under 80-A
full-load conditions was measured as approximately ll-V peak-to-peak (Figure 23).

4-213

VERTICAL: 50 mV/em

HORIZONTAL: 2 ms/em
V IN

= 120 V rms

VCC = 304 V de
LOAD = 80 A/5 V

Figure 22. The 4O-kHz 5-V Output Filter Ripple

VERTICAL:

2 V/em

HORIZONTAL: 2 ms/em

V IN

= 120 V rms

Vcc=304 Vde
LOAD = 80 A/5 V

Figure 23. The 6O-Hz Input Line Filter Ripple

4-214

One of the more important accomplishments of this work was the design and a
subsequent successful evaluation of the overcurrent network described in the Protection
Network Section. This network, consisting in part of current sense inductor T4 that is
placed in the primary side of the power transformer T3, not only proved its capability
to provide short circuit protection for the 80-A output but it also eliminated the need for
a capacitor to be connected in series with the primary of the power transformer T3. Usually
in bridge-type converter circuits, a low ESR, high-voltage capacitor is required to be
connected in series with the primary of the power transformer to provide protection against
transformer core saturation due to the switching time differences of the power transistors.

Table 2o Measured Regulation Characteristics
VIN
INPUT

vee

LINE

FILTER

VOLTAGE

VOLTAGE

(Vrrnsl

(Vdcl

96

237

120

304

132

335

*% Regulation

=

Vo - 26 V

Vo - 5 V

LINE
Vorn
(VI

(AI

5.00
5.00
5.00
5.00
5.00
5.00

80
5
80
5
80
5

Vorn-V o

10

10

% REG*

Vorn
(VI

(AI

0
0
0
0
0
0

26.03
25.99
26.03
26.00
26.03
25.99

2
2
2
2
2
2

Vo - 10 V

% REG*

Vorn
(VI

(AI

0.115
-0.384
0.115
0
0.11
-0.038

10.09
10.08
10.08
10.08
10.08
10.08

2.5
2.5
2.5
2.5
2.5
2.5

10

% REG*
0.9
0.8
0.8
0.8
0.8
0.8

x 100%

Vo

Figure 24 shows the T3 power transformer primary current, thereby illustrating the
excellent current symmetry characteristic obtained under various input voltage conditions
of 96 Vrms , 120 Vrms , and 132 Vrms during constant 100% load.
Figures 25 and 26 of the TIPL755 power transistor's collector voltage and current
characteristics illustrate the TIPL755 very fast switching speed that was obtained by use
of the Base Driver Section.

II
en
c:

o
0';:;
~

CD
"C

0;;
c:

o

(.)

c:

C)

0C;;
CD

o

4-215

VERTICAL:

2 A/em

HORIZONTAL: 10 /Ls/em
V IN = 96 V rms
VCC = 237 Vde
LOAD = 100% ALL OUTPUTS

VERTICAL:

2 A/em

HORIZONTAL: 10/Ls/em
V IN = 120 V rms
VCC =304 Vde
LOAD = 100% ALL OUTPUTS

IIc
CD

(I)

;fJ'
::3

n
o

::3
(I)

a:CD

...

CIl

VERTICAL:

0'

HORIZONTAL: 10/Ls/em

::3

(I)

2 A/em
V IN = 132 V rms
VCC = 335 V de
LOAD = 100% ALL OUTPUTS

Figure 24, Power Transformer Primary Current
4-216

VERTICAL:

IC = 2 A/em
VCE = 100 V/em

HORIZONTAL: 10 Ils/em

o

V IN = 132 V rms
VCC= 335 V de
LOAD = 20 A/5 V

V CED

Figure 25. TIPL755 Power Transistor Switching Characteristics
100% . . . . .

VERTICAL:

IC = 100%
VCE = 100%

HORIZONTAL: 1 Ils/em
V IN = 132 V rms
VCC = 335 Vde
LOAD= 20 A/5 V

U)

C

Figure 26. TIPL755 Power Transistor t xo Switching Characteristics

o
'4:
f!
CD

Measurements of the overall power supply efficiency were made at various input
voltages, while load conditions were changed from 50% to 100% full load, at each input
voltage. An efficiency of 65 to 67% was measured, see Table 3.
In conclusion, the measurement results that were obtained proved the power supply
described in this report did meet or exceed all of the requirements of the Power Supply
Specification.

"0

.;
C

o

CJ

c

.;0)
CD

C

Figure 27 shows the power supply as constructed for this report.

4-217

Table 3. Power Supply Efficiency and Power Factor
VIN
(Vrmsl

liN
(Armsl

PIN
(WI

100
99.2
112.8
113.9
132
132

9.49
5.78
8.9
5.3
7.46
4.67

721
419
738
426
733
435

POWER FACTOR
PIN
VINxllN

0.759
0.731
0.735
0.704
0.744
0.705

V o ·5V
10
(AI
80
40

80
40
80
40

POWER OUTPUTS
V o .10 V
V o .26 V

P1
(WI
400

200
400
200
400
200

10
(AI

P2
(WI

10
(AI

Pa
(WI

3
3
3
3
3
3

30
30
30
30
30
30

2
2
2
2
2
2

52
52
52
52
52
52

% EFFICIENCY
Pa
". P1 +P2+
PIN

67
67
65
66
66
65

c

(I
(II

cO·
:::s

n
o
:::s

(II

c:

...o·..

(I

II)

:::s

(II

4-218

Figure 27. The SOO-W, SO-A, OtT-the-Line, Half-Bridge Converter
Switching Power Supply

S1

r--':':-':-:;

SCR2

'I--..-.W,,-~'t TIC1Z6A

"

"H+t----1

"
"
14

.12

4.7K

NOTES

I. ALL RESISTOR VALUES ARE IN OHMS. ALL RESISTORS
ARE 1/4W,5% TOLERANCE UNLESS OTHERWise NOTED.
2. ALL CAPACITANCE VlAUES ARE IN jJF UNLESS
DTttERWlSENOHO.

.lI

56'

....

Figure 28. SOO-W, 80-A Switching Power Supply

N
CD

Design Considerations

II

Q8
TlP125

FROM
PAGE 26
A

r-----'I

I
I

R43
0.5,2W

+10 V
2.5 A

I
R45
100
L ___

'C7
R44
1
1W

R48
82
R49
590
1%

A'
Q10
TlP125

FROM
PAGE 26

•

r-----'I

I
I

R50
0.5,2W

I

B

+26 V
2A

I
I

I
I

R52
100

C
CD

L ___

en
:::s

='n

I
I

__ J

C34
0.1
200 V

0

:::s
en

a:CD

R51

.

1,1 W
R55
82

C»

r+

0'
:::s
en

R56
1.6K

B'

Figure 29. Linear Post Regulators

4-220

Acknowledgment
The authors wish to thank Ira N. Frost of the Texas Instruments Linear Applications
Lab for his most valuable assistance in this project.
Acknowledgement of important technical information received from Texas
Instruments ORC engineers, Carl B. Jones and John H. Vincent, is also given with our
appreciation.

References
1.

John Spencer, Designing Switching Voltage Regulators with TIA94, A Texas
Instruments Application Report, Bulletin CA-198.

2.

Peter Wilson, The TIA9415 Switching Regulator, A Texas Instruments Application
Report, Bulletin B209.

3.

Switching Power Supply Design Student Guide, Texas Instruments Incorporated,
Semiconductor Group Regional Technology Center.

U)

C

o
'';::;

.
ca

Q)

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C

4-221

Parts List
CIRCUIT

QTY.
2

DESCRIPTION

DESIGNATOR

C1, C2

2500-/LF, 250-V Electrolytic Capacitor, Sprague
36DX252F250BF2A

2

C3, C4

25-/LF, 25-V Electrolytic Capacitor, Sprague 5000

2

C5,C6

0.0056-/LF, 600-V Polypropylene Capacitor, Sprague

2

C7,C8

4-/LF, 400-V Polypropylene Capacitor (made up of 2

1

C10

715P56296JA3
each 2-/LF Sprague 735P205X9400UTL in parallel)
1OOO-/LF, 50-V Electrolytic Capacitor, Sprague
6740108H050HL5A
1

C11

270-/LF, 50-V Electrolytic Capacitor, Sprague
6740277H050HE5A

1

C12

100-/LF, 50-V Electrolytic Capacitor, Sprague
6720107H0500T5C

c
CD

(I)

1

C13

0.47-/LF, 100-V Mylar Capacitor, Sprague 225P

2

C14, C19

0.01-/LF, 200-V Mylar Capacitor, Sprague

1

C15

25-/LF, 12-V Electrolytic Capacitor, Sprague 5000

1

C16

0.033-/LF, 100-V Mylar Capacitor, Sprague 225P

1

C17

0.022-/LF, 100-V Mylar Capacitor, Sprague 225P

1

C18

0.001-/LF, 200-V Mylar Capacitor, Sprague 192P

1

C20

0.0033-/LF, 100-V Mylar Capacitor, Sprague 225P

2

C23, C24

0.056-/LF, 200-V Polypropylene Capacitor, Sprague

1

C25

715P56392K

cE'
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C')

5

C26, C28, C30, C32,C34

1

C27

o

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15,OOO-/LF, 715-V Electrolytic Capacitor, Sprague
6740159H7R5JT5A
0.1-/LF, 200-V Polypropylene Capacitor, Sprague
715P10402L
680-/LF, 20-V Electrolytic Capacitor, Sprague
6720687H020ET5C

1

C29

1

01

25-A, 600-V Bridge Rectifier, Varo VT600S

02, 03, 06, 07, 08, 09,

1 N4001 Oiode

330-/LF, 40-V Electrolytic Capacitor, Sprague
6720337H040ET5C

12

010,011,018,019,020,
021

4-222

2

04, 05

4-A, 600-V Fast-Recovery Oiode, TRW OSR5600X

2

012,013

75-A, 45-V Power Schottky Oiode, TRW S075

2

014,015

10-A, 200-V Fast-Recovery Oiode, Varo VH248X

1

IC1

15-V, 1.5-A Positive Voltage Regulator, TI uA7815C

PARTS LIST (continued)
CIRCUIT
DESIGNATOR

QTY.

DESCRIPTION

1

IC2

5-V. 1.5-A Positive Voltage Regulator. TI uA7805C

1
1

IC3
IC4

Pulsewidth Modulator Control Circuit. TI TL494CN
Overvoltage-Sensing Circuit. TI MC3423CP

1

IC5

1

IC6

High-Current Darlington Switch. TI ULN2066B
Peripheral OR Driver. TI SN75413

2
1

IC7.IC8
L1

1

L2

Output Inductor. 590-"H. 4-A. Pulse Engineering
PE50731

1

L3

1

T1

Output Inductor. 2350-"H. 2-A. Pulse Engineering
PE50732
60-Hz Auxiliary Transformer. Triad-Utrad F-211 Z

1

T2

1.5-A. 3-Terminal Adjustable Regulator. TI LM317
Output Inductor. 8-"H. 1~O-A. Pulse Engineering
PE50742

20-kHz Base Drive Transformer. Pulse Engineering
PE62129

1

T3

20-kHz Switching Transformer. Pulse Engineering
PE63202

1

T4

Current Sense Inductor. Pulse Engineering PE51 719

1

Z1

Line Filter. 220-V. 10-A. Pulse Engineering PE622A10

1

R1

.1

R2

100-kO Resistor. 1/4 W. 5%
Thermistor. 2.50 (cold). 0.0450 (hot). 10-A. 5%.
Rodan-Surge-Guard SG-7

...
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C

2

R3. R4

3.5 kO Resistor. 10 W. 5%

2

R5. R7

5-0 Resistor. 5 W. 5%

"

2
2
1

R6. R8
R9. R10
R11

68-0 Resistor. 1/4 W. 5%
50-0. Resistor. 12 W. 5%
5.6-kO Resistor. 1/4 W. 5%

CU
't:J

"wC

2

R12. R36

4.7-kO Resistor. 1/4 W. 5%

(.)

2

R13. R15

1

R14
R16

12-kO Resistor. 1/4 W. 5%
Potentiometer. 1 kO
750-0 Resistor. 1/4 W. 5%

1
2

R17. R18

470-0 Resistor. 1/4 W. 5%

1

R19

6.8-kO Resistor. 1/4 W. 5%

1

R20

1
1

R21
R22

130-kO Resistor. 1/4 W. 5%
1.5-kO Resistor. 1/4 W. 5%
Potentiometer. 20 kO

5

R23. R33. R34. R47. R54
R24

27-kO Resistor. 1/4 W. 5%

1

o
as

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c

0)

"wCU

C

1-kO Resistor. 1/4. 5%

4-223

PARTS LIST (continued)

1
2
2

CIRCUIT
DESIGNATOR
R25
R26, R27
R28, R29

2
1
1
1
1

R30, R37
R31
R32
R35
R40

Potentiometer, 10 kD
51-D Resistor, 1/4 W, 5%
330-D Resistor, 114 W, 5%
6.1-kD Resistor, 1/4 W, 5%
56-kD Resistor, 112 W, 5%
100-D Resistor, 1/4 W, 5%
47-D Resistor, 1/4 W, 5%
10-D Resistor, 1/4 W, 5%

2
1
2
2
2

R41, R42
R43, R50
R44, R51
R45,R52
R48, R55

10-D Resistor, 112 W, 5%
0.5-D Resistor, 2 W, 5%
1-D Resistor, 1 W, 5%
100-D Resistor, 1/4 W, 5%
82-D Resistor, 1/4 W, 5%

1
1
2
2
1

R49
R56
Q1, Q3
Q2,Q4
Q5

590-D Resistor, 1/4 W, 1 %
1.6-kD Resistor, 114 W, 5%
10-A, 800-V, NPN Fast-Switching Transistor, TIPL755
6-A, 40-V, NPN Transistor, TIP41
0.2-A, 40-V, PNP Transistor, A8T3702 or MPS3702

1
2
2
1
1

Q6
Q7,Q9
Q8,Q10
SCR1
SCR2

0.8-A, 50-V, NPN Transistor, A8T3704 or MPS3704
6-A, 40-V, PNP Transistor, TIP42
5-A, 60-V, PNP Darlington Transistor, TIP125
Sensitive-Gate Thyristor, 2N5060
12-A, 100-V Thyristor, TIC126A

1
1
1
1
1

HS1
HS2
HS3
HS4
11

1
1

S1
S2

Schottky Rectifier Heat Sink, Thermalloy 6423B
Power Transistor Heat Sink, Thermalloy 6123B
Clip-On Heat Sink, Linear Regulators, Thermalloy THM 6038B
Power Transistor Heat Sink, Thermalloy THM 6025
Indicator Light
Klixon 15-A Circuit Breaker, TI MC8-122-15
Triple-Pole, Double-Throw Switch

OTY.

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cS'
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a:CD

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(I)

4-224

DESCRIPTION

~_M_e_C_h_a_ni_c_a_I_D_at_a________________L~

5-1

Contents
Page
Ordering Instructions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..
Mechanical Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..

C

....
I»
I»

•
5-2

5-3
5-4

ORDERING INSTRUCTIONS

ORDERING INSTRUCTIONS
Electrical characteristics presented in this data book, unless otherwise noted, apply for the circuit type(s) listed
in the page heading regardless of package. The availability of a circuit function in a particular package is denoted
by an alphabetical reference above the pin-connection diagram(s). These alphabetical references refer to
mechanical outline drawings shown in this section.
Factory orders for circuits described in this data book should include a four-part type number as explained in
the following example.
EXAMPLE:

TL

317M

JG

/883B

prefix----------------------------'!
MUST CONTAIN TWO OR THREE LETTERS
TL ..................... TI linear Products
STANDARD SECOND-SOURCE PREFIXES
LT. . . .. linear Technology
LTC. . .. linear Technology
LM . . . . . . . . . . .. National
MC ........... Motorola

SG ....... Silicon General
uA . . . . .. Fairchild/National
UC . . . . . . . . . . .. Unitrode

ca
ca

Unique Circuit Description Including Temperature Range - - - - - - '

~

MUST CONTAIN THREE OR MORE CHARACTERS
(From Individual Data Sheets)

C

Examples:

'2
ca

317M
497A
79M24

cau

79L15A
79L12AC

.c
u
CD

Package _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _--J

:E

II

MUST CONTAIN ONE OR TWO LETTERS
0, OW, FN, J,JG, KA, KC, KJ, KK, KV, L, LD, LP, N, P, U
(From Pin-Connection Diagrams on Individual Data Sheet)
MIL-STD-883B, Method 5004, Class B _ _ _ _ _ _ _- - J
OMIT/BB3B WHEN NOT APPLICABLE

Circuits are shipped in one of the carriers below. Unless a specific method of shipment is specified by the customer
(with possible additional costs), circuits will be shipped in the most practical carrier.
Small Outline (0, OW)
Dual-In-line (J, JG, N, P)
- Slide Magazines
-A-Channel Plastic Tubing
- Sectioned Cardboard Box
-Individual Cardboard Box

Power Tab (KA, KC,KJ, KK,KV)
-Sleeves
Chip Carriers (FN)
-Anti-Static Plastic Tubing
Flat (U)
- Milton Ross Carrier

TEXAS . "

INSTRUMENTS
POST OFFICE BOX 655012 • DALLAS, TEXAS 75265

Plug-In (L, LD, LP)
-Sectional Cardboard Box
-Individual Cardboard Box

5-3

MECHANICAL DATA

0008. 0014. and 0016 plastic "small outline" packages
Each of these "small outline" packages consists ot a circuit mounted on a lead frame and encapsulated
within a plastic compound. The compound will withstand soldering temperature with no deformation, and
circuit performance characteristics will remain stable when operated in high-humidity conditions. Leads
require no additional cleaning or processing when used in soldered assembly.

0008.0014, and 0016
(16-pin package used for illustration)

f

6.20 (0.2441

,-

I

5.80 (0.2281
4.00 (0.1571
3.81 (0.1501

*----~~::;:;=;:;::;:;:::;:;::~
1.75 (0.0691
1.35 (0.0531

r

T' NOM

4 PLACES

-i----

jl~
0.356 (0.0141

0.28 (0.0111

PIN SPACING

1.27 (0.0501

(See Note AI

~
DIM

A MIN
A MAX

8

14

16

4,80
(0.189)
5,00
(0.197)

8,55
(0.337)
8,74
(0.344)

9,80
(0.386)
10,00
(0.394)

ALL LINEAR DIMENSIONS ARE IN MILLIMETERS AND PARENTHETICALLY IN INCHES
NOTES: A.
B.
C.
D.

5-4

leads are within 0,25 (0.010) radius of true position at maximum material dimension.
Body dimensions do not include mold flash or protrusion.
Mold flash or protrusion shall not exceed 0,15 (0.006).
Lead tips to be planar within ±O,051 (0.002) exclusive of solder.

TEXAS

~

INSTRUMENTS
POST OFFICE BOX 855012 • DALLAS, TEXAS 75265

MECHANICAL DATA

DW016. DW020. DW024. and DW028 plastic "small outline" packages
Each of these "small outline" packages consists of a circuit mounted on a lead frame and encapsulated
within a plastic compound. The compound will withstand soldering temperature with no deformation, and
circuit performance characteristics will remain stable when operated in high-humidity conditions. Leads
require no additional cleaning or processing when used in soldered assembly.

DW016, DW020, DW024, and DW028
(20-pin package used for iHustTatlon)

9,0 (0.3541

0,5 (0.021 X

45"LC--~--'

rl::r-

~1ll
P

r 4" 4"
~
•

0,785 10.031)

~

,

'

U1.27

~I

\-7"NOM


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