SC2422A

BIPHASE CURRENT MODE

CONTROLLER

© 2000 SEMTECH CORP.

652 MITCHELL ROAD NEWBURY PARK CA 91320

PRELIMINARY - August 7, 2000

4

PIN CONFIGURATION

Top View

(16-Pin SOIC)

FUNCTIONAL BLOCK DIAGRAM

PIN DESCRIPTION

Pin 1: VID4 , MSB

Pin 2: VID3

Pin 3: VID2

Pin 4: VID 1

Pin 5: VID0 , LSB

Pin 6: ERROUT Error-amplifier output.

Pin 7: FB Error-amplifier inverting input.

Pin 8: RREF Frequency setting resistor pin. Also pro-

grams the DAC current step size. (see application in-

formation for programming the frequency)

Pin 9: GND Chip ground.

Pin 10: UVLO Programmable Under Voltage Lock-

Out. This pin may be connected to the MOSFET driver

supply through a voltage divider to inhibit the SC2422A

until the drivers are on. The UVLO comparator trip

point is 1.5V.

Pin 11: OC- Input current sense, negative input. This

pin is connected to the input supply side of the current

sense resistor.

Pin 12: OUT2 PWM output for phase 2. Drives exter-

nal Power MOSFET driver.

Pin 13: OUT1 PWM output for phase 1. Drives exter-

nal Power MOSFET driver.

Pin 14: OC+ Input current sense positive input. This

pin is connected to MOSFET side of the current sense

resistor.

Pin 15: BGOUT Soft start and reference. Bypass to

ground (GSEN) with a .022µF - 0.1µF capacitor to im-

plement soft start in conjunction with internal 3K

Ω re-

sistor. To ensure output voltage accuracy, the maxi-

mum current source/sink from this pin should be lim-

ited to 0.5 uA.

Pin 16: VCC Chip positive supply.