ISSUE 1 - JANUARY 2001

ZXSC100

6

Pin

No.

Name

Description

1

EM

Emitter of internal drive transistor. Connect to RE in lower power applications.

Must be unconnected in higher power applications

2

BAS

Not connected in lower power applications. Connect to base of external drive

transistor in higher power applications

3

RE

Connected external sense resistor. Connect emitter of external drive transistor in

higher power applications

Supply voltage, generally NiMH, NiCd single cell

Inductor current sense input. Internal threshold voltage set to 25mV. Connect

external sense resistor

6

FB

Feedback sense. Internal threshold set to 730mV. Connect external resistive

divider to output voltage

Ground

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

switching transistor. Also connect to collector of external drive transistor in

higher power applications

PIN DESCRIPTIONS

RE

EM

BAS

VDRIVE

VCC

ISENSE

FB

GND

5

6

7

8

4

3

2

1

REFERENCE DESIGNS

Three typical DC-DC step-up converter applications

for the ZXSC100 are shown. Firstly with a maximum

output power of 0.33W, secondly with a maximum

output power of 1.0W and finally driving white LED’sin

a flashlight application.

Low Power Solution (330mW) Efficiency