PROGRAMMABLE, HIGH PERFORMANCE

MULTI-PHASE, PWM CONTROLLER

SC1144

© 1999 SEMTECH CORP.

652 MITCHELL ROAD NEWBURY PARK CA 91320

Preliminary - August 24, 1999

1

The SC1144 is patent pending

Pentium is a registered trademark of Intel Corporation

BLOCK DIAGRAM

PIN CONFIGURATION

FEATURES

APPLICATIONS

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

DEVICE

(1)

PACKAGE

TEMP. (T

SC1144ABCSW

SO-24

0 - 85°C

ORDERING INFORMATION

Note:

(1) Add suffix ‘TR’ for tape and reel.

DESCRIPTION

The SC1144 is a high performance, multi-phase

(PWM) controller designed for high power micropro-

cessors requiring ultra fast transient response, such as

the Pentium

unique design, the controller distributes the output load

across (up to) four converter channels by digitally

phase shifting the PWM outputs. This approach

greatly reduces the stress and heat on the output

stage components while lowering input ripple current

by as much as 80%. Accurate current sharing among

the four phases is achieved by precision design tech-

niques and trimming of critical elements.

The high speed transconductance error amplifier is

externally initialized using a soft-start capacitor allow-

ing the controller to “wake-up” without overshoot, thus

protecting the low voltage microprocessor loads. The

output drive voltage to the power MOSFETs is pro-

grammable to minimize switching losses in the drive

circuitry.

The floating feedback ground allows remote sense ca-

pability. The output voltage is digitally programmable

by means of a 5 bit DAC. A single resistor programs

the master clock frequency (8MHz max) or the con-

troller may be synchronized using an external oscilla-

tor. The number of operating phases is programmed

independently of the external clock. The parts features

under-voltage lock-out with hysteresis and over-

current protection.

(24-Pin SOIC)

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