ZXSC300 Datasheet. Www.s Manuals.com. Zetex

User Manual: Marking of electronic components, SMD Codes C3, C3**, C3-, C3-**, C3-***, C30, C300, C323TS, C327, C32716, C32725, C32740, C337, C33716, C33725, C33740, C3415S, C343TS, C3615, C3616, C3619, C363ES, C3=**, C3G, C3J, C3W, C3p, C3t. Datasheets 1SS226, 1SS302, 2PD601ART, 2SC3415S, 2SC3615, 2SC3616, 2SC3619, APS1016ES5-1.8, BC327, BC327-16, BC327-25, BC327-40, BC337, BC337-16, BC337-25, BC337-40, BZT52H-C56, BZX585-B3V0, CMLDM7003, CMLDM7003G, CMLDM7003J, DTC323TS, DTC343TS, DTC363ES, KST4126, RT8020BGQW, RT8020

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ZXSC300
SINGLE OR MULTI CELL LED DRIVER SOLUTION

DESCRIPTION
The ZXSC300 is a single or multi cell LED driver
designed for applications where step-up voltage
conversion from very low input voltages is required.
These applications mainly operate from single 1.5V or
1.2V battery cells. The circuit generates constant
current pulses that are ideal for driving single or
multiple LED’s over a wide range of operating voltages.

The circuit can start up under full load and operates
down to an input voltage of 0.8 volts. The solution
configuration ensures optimum efficiency over a wide
range of load currents, several circuit configurations
are possible depending on battery life versus
brightness considerations.
The ZXSC300 is offered in the SOT23-5 package which,
when combined with a SOT23 switching transistor,
generates a high efficiency small size circuit solution.
The IC and discrete combination offers the ultimate
cost vs performance solution for single cell LED driving
applications.

The ZXSC300 is a PFM controller IC that drives an
external Zetex switching transistor with a very low
saturation resistance. These transistors are the best
switching devices available for this type of switching
conversion enabling high efficiency conversion with
input voltages below 1 volt. The drive output of the
ZXSC controller generates a dynamic drive signal for
the switching transistor.

FEATURES

APPLICATIONS

• 94% efficiency

• LED flashlights and torches

• Minimum operating input voltage 0.8V

• LED backlights

• Fixed output current

• White LED driving

• Low saturation voltage switching transistor

• Multiple LED driving

• SOT23-5 package

• Solar Equipment

TYPICAL APPLICATION CIRCUIT

ORDERING INFORMATION

VBATT

DEVICE

L1
100µH

U1
Vcc
Vdrive

ZXSC300E5TA

Tapewidth

7”

8mm

Q1
FMMT617

DEVICE MARKING C300

LED1

Package SOT23-5

WHITE LED

Isense
Gnd
ZXSC300

Reel

R1
0.33R

ISSUE 3 - NOVEMBER 2006
1

Quantity
per reel
3,000

ZXSC300
ABSOLUTE MAXIMUM RATING
Operating Temperature
Storage Temperature

Supply Voltage
-0.3 to 10V
Maximum Voltage Other Pins -0.3 to VCC+0.3V
Power Dissipation
450mW

-40 to 85°C
-55 to 150°C

ELECTRICAL CHARACTERISTICS: Test conditions unless otherwise stated: VCC=1.5V, TAMB=25°C
SYMBOL

PARAMETER

CONDITIONS

MIN.

Efficiency

V CC

Recommended
supply voltage range

V CC(min)

Minimum startup
and operating
voltage

Quiescent current 2

I VDRIVE

Base drive current

MAX. UNITS

0.8

I DRIVE =-600µA, V DRIVE =0.7V

0.8

I DRIVE =-600µA, V DRIVE =0.7V,
T AMB =-10°C 3

0.9
mA

V CC -0.3

V CC

0.2

Low level drive
voltage

V ISENSE = 50mV, I VDRIVE = 5mA

V ISENSE

Output current
reference voltage

Discharge pulse width

V DRIVE = 0.7V, V ISENSE = 0V

V VDRIVE(low)

T DRV

0.92

V ISENSE = 0V, I VDRIVE =-0.5mA

I SENSE input current

3.6

High level drive
voltage

I ISENSE

0.2

V VDRIVE(high)

I SENSE
voltage temp co. 2

1.5

Supply current

T CVISENSE

V DRIVE = 0.7V, V ISENSE = 0V

I CC

(threshold)

TYP.

0.4
V ISENSE = 0V

%/°C

-30

1.2

1.7

-65
3.2

µA
µs

OPERATING CONDITIONS
SYMBOL
F OSC
1
2
3
4

PARAMETER
Recommended operating frequency

CONDITIONS

MIN.

TYP.

MAX.

UNITS

200

kHz

Application dependent, see reference designs.
These parameters guaranteed by design and characterisation
Total supply current =IQ + IVDRIVE, see typical characteristics
Operating frequency is application circuit dependent. See applications section.

ISSUE 3 - NOVEMBER 2006
2

ZXSC300
FMMT617
For the circuits described in the applications section, Zetex FMMT617 is the recommended pass transistor. The
following indicates outline data for the transistor, more detailed information can be found in the Zetex surface
mount data book or at www.zetex.com

ELECTRICAL CHARACTERISTICS (at TA = 25°C unless otherwise stated).
PARAMETER

SYMBOL MIN.

TYP.

MAX.

UNIT

CONDITIONS

Collector-Emitter
Saturation Voltage

V CE(sat)

8
70
150

14
100
200

mV
mV
mV

I C =0.1A, I B =10mA*
I C =1A, I B =10mA*
I C =3A, I B =40mA*

Collector-Emitter
Breakdown Voltage

V (BR)CEO

I C =10mA*

*Measured under pulsed conditions. Pulse width=300µs. Duty cycle ≤ 2%

ZHCS1000
For the circuits described in the applications section Zetex ZHCS1000 is the recommended Schottky diode. The
following indicates outline data for the diode, more detailed information is available at www.zetex.com

ELECTRICAL CHARACTERISTICS (at Tamb = 25°C unless otherwise stated).
PARAMETER

SYMBOL

MIN.

TYP.

Forward Voltage

Reverse Current

Reverse Recovery
Time

t rr

MAX.

UNIT

CONDITIONS

400
500

mV
mV

I F =500mA
I F =1A

100

µA

V R =30V

Switched from IF = 500mA
to IR = 500mA. Measured
at IR=50mA

*Measured under pulsed conditions. Pulse width=300µs. Duty cycle ≤ 2%

ISSUE 3 - NOVEMBER 2006
3

ZXSC300
TYPICAL CHARACTERISTICS

ISSUE 3 - NOVEMBER 2006
4

ZXSC300
DEVICE DESCRIPTION
With every on pulse the switching transistor is kept on
until the voltage across the current-sense resistor
exceeds the threshold of the ISENSE input. The on-pulse
length, and therefore the switching frequency, is
determined by the programmed peak current, the
input voltage and the input to output voltage
differential. See applications section for details.

The ZXSC300 is PFM, controller IC which, when
combined with a high performance external transistor,
enables the production of a high efficiency boost
converter for use in single cell LED driving
applications. A block diagram is shown for the
ZXSC300 in Figure 1.

The Driver circuit supplies the external switching
transistor with a fixed drive current. To maximise
efficiency the external transistor switched quickly,
typically being forced off within 30ns.

Pinout Diagram

Figure 1 ZXSC300 Block Diagram

The on chip comparator forces the driver circuit and
therefore the external switching transistor off if the
voltage at ISENSE exceeds 19mV. This threshold is set
by an internal reference circuit and divider.
The Voltage at ISENSE is taken from a current sense
resistor connected in series with the emitter of the
switching transistor. A monostable following the
output of the comparator forces the turn-off time of the
output stage to be typically 1.7µs. This ensures that
there is sufficient time to discharge the inductor coil
before the next on period.

Pin Descriptions
Pin No.

Name

Description

V CC

Supply voltage, generally Alkaline, NiMH or NiCd single cell

Gnd

Ground

N/C

Not connected

I SENSE

Inductor current sense input. Internal threshold voltage set to 19mV.
Connect external sense resistor

V DRIVE

Drive output for external switching transistor. Connect to base of external
switching transistor

ISSUE 3 - NOVEMBER 2006
5

ZXSC300
REFERENCE DESIGNS
Two typical LED driving applications are shown.
Firstly a maximum brightness solution and
secondly an optimised battery life solution.

Maximum brightness solution
This circuit provides a constant current output to
the LED by rectifying the switching pulses. This
ensures maximum LED brightness.

VBATT

100µH

U1
Vcc
Vdrive

ZHCS1000

Q1
FMMT617

Isense
Gnd
ZXSC300

LED1
WHITE LED

2.2µF

R1
0.1R

Material List
Ref

Value

Part Number

Manufacture

Comments

U1
Q1

N/A

ZXSC300E5

Zetex Plc

Single cell converter, SOT23-5

N/A

FMMT617

Zetex Plc

Low V CE(sat) NPN, SOT23

ZHCS1000

Zetex Plc

1A Shottky diode, SOT23

100mW

Generic

Various

0805 Size

2.2mF

Generic

Various

Low ESR ceramic capacitor

100µH

DO1608P-104

Coilcraft

Surface mount inductor

LED1

5600mcd

NSPW500BS

Nichia

White LED

ISSUE 3 - NOVEMBER 2006
6

ZXSC300
Maximum battery life solution
To ensure optimum efficiency, and therefore
maximum battery life, the LED is supplied with a
pulsed current. Maximum efficiency is ensured with
the removal of rectifier losses experienced in the
maximum brightness solution.

100

VBATT

Single LED Load

Vcc
Vdrive

Efficiency (%)

100µH

Q1
FMMT617

LED1
WHITE LED

Isense
Gnd
ZXSC300

0.33R

1.0

1.5

2.0

2.5

3.0

Input Voltage (V)

Input Voltage v Efficiency

Materials list
Ref

Value

Part Number

Manufacture

Comments

N/A

ZXSC300E5

Zetex Plc

Single cell converter, SOT23-5
Low V CE(SAT) NPN, SOT23

N/A

FMMT617

Zetex Plc

330mW

Generic

Various

0805 Size

100mH

DO1608P-104

Coilcraft

Surface mount inductor

LED1

5600mcd

NSPW500BS

Nichia

White LED

ISSUE 3 - NOVEMBER 2006
7

3.5

ZXSC300
APPLICATIONS INFORMATION
The following section is a design guide for optimum
converter performance.

The Zetex FMMT617 is an ideal choice of transistor,
having a low saturation voltage. A data sheet for the
FMMT617 is available on Zetex web site or through
your local Zetex sales office. Outline information is
included in the characteristics section of this data
sheet.

Switching transistor selection
The choice of switching transistor has a major impact
on the converter e fficiency. F or optim um
performance, a bipolar transistor with low VCE(SAT) and
high gain is required.

Schottky diode selection
For the maximum battery life solution a Schottky
rectifier diode is required. As with the switching
transistor the Schottky rectifier diode has a major
impact on the converter efficiency. A Schottky diode
with a low forward voltage and fast recovery time
should be used for this application.

Inductor selection has a significant impact on the
converter performance. For applications where
efficiency is critical, an inductor with a series
resistance of 500mΩ or less should be used.

The diode should be selected so that the maximum
forward current is greater or equal to the maximum
peak current in the inductor, and the maximum reverse
voltage is greater or equal to the output voltage.

The peak current rating is a design parameter whose
value is dependent upon the overall application. For
the high brightness reference designs, a peak current
of was chosen to ensure that the converter could
provide the required output power to the LED.

Peak current definition

The Zetex ZHCS1000 meets these needs. Datasheets
for the ZHCS Series are available on Zetex web site or
through your local Zetex sales office. Outline
information is included in the characteristics section of
this data sheet.

In general, the IPK value must be chosen to ensure that
the switching transistor, Q1, is in full saturation with
maximum output power conditions, assuming
worse-case input voltage and transistor gain under all
operating temperature extremes.

For the maximum brightness solution a pulsed current
is supplied to the LED therefore a Schottky rectifier
diode is not required.

Once IPK is decided the value of R SENSE can be
determined by:

Inductor selection

RSENSE =

The inductor value must be chosen to satisfy
performance, cost and size requirements of the overall
solution. For the reference designs we recommend an
inductor value of 100uH with a core saturation current
rating greater than the converter peak current value
and low series resistance.

VISENSE
IPK

where VISENSE=19mV

ISSUE 3 - NOVEMBER 2006
8

ZXSC300
Output Power Calculation
By making the above assumptions for inductance and
peak current the output power can be determined by:
(VOUT- VIN) x (IPK + IMIN)
TOFF
x
(TON + TOFF )
2

POUT =

Operating frequency can be derived by:
1
F=
(TON + TOFF )
Capacitor selection

Note: VOUT = output voltage + Schottky rectifier voltage
drop

For pulsed operation, as in the maximum battery life
solution, no capacitors are required at the output to
the LED. For rectified operation, as in the maximum
brightness solution, a small value ceramic capacitor
is required, typically 2.2uF.

where
Generally an input capacitor is not required, but a
small ceramic capacitor may be added to aid EMC,
typically 470nF to 1uF.

TOFF ≅ 1.7µs (internally set by ZXSC300)
and
TON

Demonstration board
T (V
− VIN)
= OFF OUT
VIN

A demonstration board for the Maximum battery life
solution, is available upon request. These can be
obtained through your local Zetex office or through
Zetex web pages. For all reference designs Gerber
files and bill of materials can be supplied.

and
IMIN = IPK −

( VOUT - VIN ) x TOFF
L

Layout of Maximum battery life solution

Top Copper

Drill Holes

Bottom Copper

Silk Screen

ISSUE 3 - NOVEMBER 2006
9

ZXSC300
SUPPLIER LISTING
Manufacturer

Zetex
Tel:

EUROPE

ASIA

USA

Zetex GmbH
Germany

Zetex Asia
Hong Kong

Zetex Inc

(49) 894549490

(852) 2610 0611

(1) 631 543 7100

URL:

http://www.zetex.com

AVX

AVX UK

AVX Asia
Singapore

AVX USA

Tel:

(44) 1252 770000

(65) 6286 7555

(1) 843 448 9411

URL:

http://www.avxcorp.com

Coilcraft

Coilcraft Europe
UK

Coilcraft Inc

Tel:

(44) 1236 730595

(1) 847 639 6400

URL:

Nichia Corporation
Tel:

http://www.coilcraft.com
Nichia Europe B.V.
The Netherlands

Nichia Corporation
Japan

Nichia America
Corporation

(31) 20 5060900

(81) 3 3456 3784

Head Office
(1) 717 285 2323
San Jose
(1) 408 573 0933

URL:

http://www.nichia.co.jp

ISSUE 3 - NOVEMBER 2006
10

ZXSC300
PACKAGE OUTLINE

PACKAGE DIMENSIONS
Millimeters

Inches

DIM
MIN.

MAX.

MIN.

MAX.

0.90

1.45

0.0354

0.0570

0.15

0.0059

0.90

1.30

0.0354

0.0511

0.20

0.50

0.0078

0.0196

0.09

0.26

0.0035

0.0102

2.70

3.10

0.1062

0.1220

2.20

3.20

0.0866

0.1181

1.30

1.80

0.0511

0.0708

ISSUE 3 - NOVEMBER 2006
11

0.95 REF

0.0374 REF

1.90 REF

0.0748 REF

0.10

0.60

0.0039

0.0236

0°

30°

0°

30°

ZXSC300
Definitions
Product change
Zetex Semiconductors reserves the right to alter, without notice, specifications, design, price or conditions of supply of any product or service.
Customers are solely responsible for obtaining the latest relevant information before placing orders.
Applications disclaimer
The circuits in this design/application note are offered as design ideas. It is the responsibility of the user to ensure that the circuit is fit for the user's
application and meets with the user's requirements. No representation or warranty is given and no liability whatsoever is assumed by Zetex with
respect to the accuracy or use of such information, or infringement of patents or other intellectual property rights arising from such use or otherwise.
Zetex does not assume any legal responsibility or will not be held legally liable (whether in contract, tort (including negligence), breach of statutory
duty, restriction or otherwise) for any damages, loss of profit, business, contract, opportunity or consequential loss in the use of these circuit
applications, under any circumstances.
Life support
Zetex products are specifically not authorized for use as critical components in life support devices or systems without the express written approval of
the Chief Executive Officer of Zetex Semiconductors plc. As used herein:
A. Life support devices or systems are devices or systems which:
1. are intended to implant into the body
or
2. support or sustain life and whose failure to perform when properly used in accordance with instructions
for use provided in the labeling can be reasonably expected to result in significant injury to the user.
B. A critical component is any component in a life support device or system whose failure to perform can be reasonably expected to cause the failure of
the life support device or to affect its safety or effectiveness.
Reproduction
The product specifications contained in this publication are issued to provide outline information only which (unless agreed by the company in writing)
may not be used, applied or reproduced for any purpose or form part of any order or contract or be regarded as a representation relating to the products
or services concerned.
Terms and Conditions
All products are sold subjects to Zetex' terms and conditions of sale, and this disclaimer (save in the event of a conflict between the two when the terms
of the contract shall prevail) according to region, supplied at the time of order acknowledgement.
For the latest information on technology, delivery terms and conditions and prices, please contact your nearest Zetex sales office or visit:
www.zetex.com
Quality of product
Zetex is an ISO 9001 and TS16949 certified semiconductor manufacturer.
To ensure quality of service and products we strongly advise the purchase of parts directly from Zetex Semiconductors or one of our regionally
authorized distributors. For a complete listing of authorized distributors please visit: www.zetex.com/salesnetwork
Zetex Semiconductors does not warrant or accept any liability whatsoever in respect of any parts purchased through unauthorized sales channels.
ESD (Electrostatic discharge)
Semiconductor devices are susceptible to damage by ESD. Suitable precautions should be taken when handling and transporting devices. The possible
damage to devices depends on the circumstances of the handling and transporting, and the nature of the device. The extent of damage can vary from
immediate functional or parametric malfunction to degradation of function or performance in use over time. Devices suspected of being affected
should be replaced.
Green compliance
Zetex Semiconductors is committed to environmental excellence in all aspects of its operations which includes meeting or exceeding regulatory
requirements with respect to the use of hazardous substances. Numerous successful programs have been implemented to reduce the use of hazardous
substances and/or emissions.
All Zetex components are compliant with the RoHS directive, and through this it is supporting its customers in their compliance with WEEE and ELV
directives.
Product status key:
"Preview"
Future device intended for production at some point. Samples may be available
"Active"

Product status recommended for new designs

"Last time buy (LTB)"

Device will be discontinued and last time buy period and delivery is in effect

"Not recommended for new designs"

Device is still in production to support existing designs and production

"Obsolete"
Datasheet status key:
"Draft version"

Production has been discontinued
This term denotes a very early datasheet version and contains highly provisional information, which may change in any
manner without notice.

"Provisional version"

This term denotes a pre-release datasheet. It provides a clear indication of anticipated performance. However, changes
to the test conditions and specifications may occur, at any time and without notice.

"Issue"

This term denotes an issued datasheet containing finalized specifications. However, changes to specifications may
occur, at any time and without notice.

© Zetex Semiconductors plc 2006
Europe
Zetex GmbH
Kustermann-Park
Balanstraße 59
D-81673 München
Germany
Telefon: (49) 89 45 49 49 0
Fax: (49) 89 45 49 49 49
europe.sales@zetex.com

Americas

Asia Pacific

Corporate Headquarters

Zetex Inc
700 Veterans Memorial Hwy
Hauppauge, NY 11788
USA

Zetex (Asia) Ltd
3701-04 Metroplaza Tower 1
Hing Fong Road, Kwai Fong
Hong Kong

Zetex Semiconductors plc
Zetex Technology Park
Chadderton, Oldham, OL9 9LL
United Kingdom

Telephone: (1) 631 360 2222
Fax: (1) 631 360 8222
usa.sales@zetex.com

Telephone: (852) 26100 611
Fax: (852) 24250 494
asia.sales@zetex.com

Telephone (44) 161 622 4444
Fax: (44) 161 622 4446
hq@zetex.com

ISSUE 3 - NOVEMBER 2006
12

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