ZXSC100
PIN DESCRIPTIONS
Pin Name Description
No.
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
Drive current sense input. Internal threshold voltage set 25mV below VCC.
Connected external sense resistor. Connect emitter of external drive transistor in
higher power applications
4
VCC
Supply voltage, generally NiMH, NiCd single cell
5
ISENSE 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
7
GND
Ground
8
VDRIVE 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
EM
BAS
RE
VCC
1
8
2
7
3
6
4
5
VDRIVE
GND
FB
ISENSE
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’s in
a flashlight application.
Low Power Solution (330mW) Efficiency
6
ISSUE 1 - JANUARY 2001