SC1650 Datasheet, PDF (4/4 Pages) Semtech Corporation – HIGH-VOLTAGE INVERTING DC-DC CONVERTER

January 29, 1998
OUTLINE DRAWING - SO-8
HIGH-VOLTAGE INVERTING
DC-DC CONVERTER
SC1650
PIN CONFIGURATION
PIN DESCRIPTIONS
PIN 1: V⁺
4V to 24V input supply voltage.
PIN 2: V_REF
1.22V reference output. Bypass with a
0.047µF capacitor to GND. Sourcing
capability is guaranteed to be greater
than 250µA.
PIN 3: SHDN Logic input to shutdown the chip.
>1.5V = normal operation,
GND = shutdown
In shutdown mode DLOW and DHI
pins are high.
PIN 4: FB
PIN 5: GND
Feedback signal input to comparator.
Connecting a resistance R1 to V_OUT
and a resistance R2 to V_REF yields the
output voltage:
V _OUT
=
-
R1
R2
* V _REF
Power ground.
PIN 6: DLOW Driver sinking output. Connected to
DHI when using an external P-channel
MOSFET. When using an external
PNP bipolar transistor, connect a
resistor R_B from this pin to DHI. R_B
value depends upon V⁺, inductor value
and the PNP bipolar transistor. By
adjusting the R_B value, efficiency can
be optimized.
PIN 7: DHI
Driver sourcing output. Connect to
the gate of the external P-channel
MOSFET or base of the PNP bipolar
transistor.
PIN 8: CL
Current-limit input. This pin clamps the
switch peak current under abnormal
conditions.
© 1997 SEMTECH CORP.
652 MITCHELL ROAD NEWBURY PARK CA 91320