SC1157

PROGRAMMABLE SYNCHRONOUS DC/DC

CONTROLLER FOR ADVANCED PROCESSORS

© 2000 SEMTECH CORP.

652 MITCHELL ROAD NEWBURY PARK CA 91320

Preliminary - August 7, 2000

1

Pentium is a registered trademark of Intel Corporation

BLOCK DIAGRAM

PIN CONFIGURATION

Top View

(16-Pin SOIC)

DESCRIPTION

The SC1157 is a low-cost, full featured, synchronous

voltage-mode controller designed for use in single

ended power supply applications where efficiency is of

primary concern. Synchronous operation allows for the

elimination of heat sinks in many applications. The

SC1157 is ideal for implementing DC/DC converters

needed to power advanced microprocessors such as

Pentium

cessor configurations. Internal level-shift, high-side

drive circuitry, and preset shoot-thru control, allows for

use of inexpensive n-channel power switches.

SC1157 features include an integrated 4-bit V

temperature compensated voltage reference, triangle

wave oscillator, current limit comparator, frequency

shift over-current protection, and an internally compen-

sated error amplifier.

The SC1157 operates at a fixed 140KHz, providing an

optimum compromise between efficiency, external

component size, and cost.

FEATURES

(1% tolerance)

APPLICATIONS

TEL:805-498-2111 FAX:805-498-3804 WEB:http://www.semtech.com

DEVICE

(1)

PACKAGE

(2)

TEMP. RANGE (T

SC1157CS.TR

SO-16NB

0 - 125°C

ORDERING INFORMATION

Note:

(1) Only available in tape and reel packaging. A reel

contains 2500 devices.

(2) “NB” indicates 150 MIL body.

R

S

Q

+

-

70mV

+

-

+

-

ERROR

AMP

D/A

SHOOT-THRU

CONTROL

VCC

CS-

BSTH

DH

SHUTDOWN

CS+

BSTL

DL

PGND

VOSENSE

REF

VID2

VID1

VID0

GND

REF

CURRENT

LIMIT

LEVEL SHIFT AND

HIGH SIDE DRIVE

SYNCHRONOUS

MOSFET DRIVE

OSCILLATOR

VID3