DM74LS390 Dual 4 Bit Decade Counter 74390

User Manual: 74390

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Revised March 2000

DM74LS390
Dual 4-Bit Decade Counter
General Description

Features

Each of these monolithic circuits contains eight masterslave flip-flops and additional gating to implement two individual four-bit counters in a single package. The
DM74LS390 incorporates dual divide-by-two and divideby-five counters, which can be used to implement cycle
lengths equal to any whole and/or cumulative multiples of 2
and/or 5 up to divide-by-100. When connected as a bi-quinary counter, the separate divide-by-two circuit can be
used to provide symmetry (a square wave) at the final output stage. The DM74LS390 has parallel outputs from each
counter stage so that any submultiple of the input count frequency is available for system-timing signals.

■ Dual version of the popular DM74LS90
■ DM74LS390...individual clocks for A and B flip-flops
provide dual ÷ 2 and ÷ 5 counters
■ Direct clear for each 4-bit counter
■ Dual 4-bit version can significantly improve system densities by reducing counter package count by 50%
■ Typical maximum count frequency...35 MHz
■ Buffered outputs reduce possibility of collector commutation

Ordering Code:
Order Number

Package Number

Package Description

DM74LS390M

M16A

16-Lead Small Outline Integrated Circuit (SOIC), JEDEC MS-012, 0.150 Narrow

DM74LS390N

N16E

16-Lead Plastic Dual-In-Line Package (PDIP), JEDEC MS-001, 0.300 Wide

Devices also available in Tape and Reel. Specify by appending the suffix letter “X” to the ordering code.

Connection Diagram

© 2000 Fairchild Semiconductor Corporation

DS006433

www.fairchildsemi.com

DM74LS390 Dual 4-Bit Decade Counter

August 1986

DM74LS390

Function Tables
Bi-Quinary (5-2)

BCD Count Sequence
(Each Counter) (Note 1)
Count

(Each Counter) (Note 2)

Outputs
QD

QC

QB

QA

0

L

L

L

L

1

L

L

L

2

L

L

3

L

L

4

L

H

5

L

H

6

L

H

7

L

H

8

H

9

H

Count

QD

QC

0

L

L

L

L

H

1

L

L

L

H

H

L

2

L

L

H

L

H

H

3

L

L

H

H

L

L

4

L

H

L

L

L

H

5

H

L

L

L

H

L

6

H

L

L

H

H

H

7

H

L

H

L

L

L

L

8

H

L

H

H

L

L

H

9

H

H

L

L

H = HIGH Level
L = LOW Level
Note 1: Output QA is connected to input B for BCD count.
Note 2: Output QD is connected to input A for Bi-quinary count.

Logic Diagram

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Outputs
QA

2

QB

Supply Voltage

7V

Note 3: The “Absolute Maximum Ratings” are those values beyond which
the safety of the device cannot be guaranteed. The device should not be
operated at these limits. The parametric values defined in the Electrical
Characteristics tables are not guaranteed at the absolute maximum ratings.
The “Recommended Operating Conditions” table will define the conditions
for actual device operation.

Input Voltage
Clear

7V

A or B

5.5V
0°C to +70°C

Operating Free Air Temperature Range

−65°C to +150°C

Storage Temperature Range

Recommended Operating Conditions
Symbol

Parameter

Min

Nom

Max

4.75

5

5.25

Units

VCC

Supply Voltage

VIH

HIGH Level Input Voltage

VIL

LOW Level Input Voltage

0.8

V

IOH

HIGH Level Output Current

−0.4

mA

IOL

LOW Level Output Current

8

mA

fCLK

Clock Frequency (Note 4)

fCLK
tW

Clock Frequency (Note 5)
Pulse Width (Note 4)

V

2

V

A to QA

0

25

B to QB

0

20

A to QA

0

20

B to QB

0

15

A

20

B

25

Clear HIGH

20

tREL

Clear Release Time (Note 6)(Note 7)

TA

Free Air Operating Temperature

MHz
MHz

ns

25↓

ns

0

°C

70

Note 4: CL = 15 pF, RL = 2 kΩ, TA = 25°C and VCC = 5V.
Note 5: CL = 50 pF, RL = 2 kΩ, TA = 25°C and VCC = 5V.
Note 6: The symbol (↓) indicates the falling edge of the clear pulse is used for reference.
Note 7: TA = 25°C and VCC = 5V.

Electrical Characteristics
over recommended operating free air temperature range (unless otherwise noted)
Symbol

Parameter

Conditions

VI

Input Clamp Voltage

VCC = Min, II = −18 mA

VOH

HIGH Level

VCC = Min, IOH = Max

Output Voltage

VIL = Max, VIH = Min

VOL

LOW Level

VCC = Min, IOL = Max

Output Voltage

VIL = Max, VIH = Min

Min

2.7

IOL = 4 mA, VCC = Min
II

IIH

IIL

Typ
(Note 8)

Max

Units

−1.5

V

3.4

V

0.35

0.5

0.25

0.4

Input Current @ Max

VCC = Max, VI = 7V

Clear

Input Voltage

VCC = Max

A

0.2

VI = 5.5V

B

0.4

0.1

HIGH Level

VCC = Max

Clear

20

Input Current

VI = 2.7V

A

40

B

80

LOW Level

VCC = Max, VI = 0.4V

Input Current
IOS

Short Circuit Output Current

VCC = Max (Note 9)

ICC

Supply Current

VCC = Max (Note 10)

V

Clear

−0.4

A

−1.6

B

−2.4
−20
15

mA

µA

mA

−100

mA

26

mA

Note 8: All typicals are at VCC = 5V, TA = 25°C.
Note 9: Not more than one output should be shorted at a time, and the duration should not exceed one second.
Note 10: ICC is measured with all outputs OPEN, both CLEAR inputs grounded following momentary connection to 4.5 and all other inputs grounded.

3

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DM74LS390

Absolute Maximum Ratings(Note 3)

DM74LS390

Switching Characteristics
at VCC = 5V and TA = 25°C
RL = 2 kΩ
Symbol
fMAX
tPLH

Parameter

Min

Maximum Clock

A to QA

25

20

Frequency

B to QB

20

15

Propagation Delay Time
Propagation Delay Time
HIGH-to-LOW Level Output

tPLH

Propagation Delay Time
LOW-to-HIGH Level Output

tPHL

Propagation Delay Time
HIGH-to-LOW Level Output

tPLH

Propagation Delay Time
LOW-to-HIGH Level Output

tPHL

Propagation Delay Time
HIGH-to-LOW Level Output

tPLH

Propagation Delay Time
LOW-to-HIGH Level Output

tPHL

Propagation Delay Time
HIGH-to-LOW Level Output

tPLH

Propagation Delay Time
LOW-to-HIGH Level Output

tPHL

Propagation Delay Time
HIGH-to-LOW Level Output

tPHL

Propagation Delay Time
HIGH-to-LOW Level Output

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Max

CL = 50 pF

To (Output)

LOW-to-HIGH Level Output
tPHL

CL = 15 pF

From (Input)

Min

Units

Max
MHz

A to QA

20

24

ns

A to QA

20

30

ns

A to QC

60

81

ns

A to QC

60

81

ns

B to QB

21

27

ns

B to QB

21

33

ns

B to QC

39

51

ns

B to QC

39

54

ns

B to QD

21

27

ns

B to QD

21

33

ns

Clear to Any Q

39

45

ns

4

DM74LS390

Physical Dimensions inches (millimeters) unless otherwise noted

16-Lead Small Outline Integrated Circuit (SOIC), JEDEC MS-012, 0.150 Narrow
Package Number M16A

5

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DM74LS390 Dual 4-Bit Decade Counter

16-Lead Plastic Dual-In-Line Package (PDIP), JEDEC MS-001, 0.300 Wide
Package Number N16E

Fairchild does not assume any responsibility for use of any circuitry described, no circuit patent licenses are implied and
Fairchild reserves the right at any time without notice to change said circuitry and specifications.
LIFE SUPPORT POLICY
FAIRCHILD’S PRODUCTS ARE NOT AUTHORIZED FOR USE AS CRITICAL COMPONENTS IN LIFE SUPPORT
DEVICES OR SYSTEMS WITHOUT THE EXPRESS WRITTEN APPROVAL OF THE PRESIDENT OF FAIRCHILD
SEMICONDUCTOR CORPORATION. As used herein:
2. A critical component in any component of a life support
device or system whose failure to perform can be reasonably expected to cause the failure of the life support
device or system, or to affect its safety or effectiveness.

1. Life support devices or systems are devices or systems
which, (a) are intended for surgical implant into the
body, or (b) support or sustain life, and (c) whose failure
to perform when properly used in accordance with
instructions for use provided in the labeling, can be reasonably expected to result in a significant injury to the
user.

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Title                           : DM74LS390 Dual 4-Bit Decade Counter
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