SC1102

SYNCHRONOUS DC/DC CONTROLLER FOR

DISTRIBUTED POWER SUPPLY APPLICATIONS

© 2000 SEMTECH CORP.

652 MITCHELL ROAD NEWBURY PARK CA 91320

September 5, 2000

1

DESCRIPTION

The SC1102 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

SC1102 is ideal for implementing DC/DC converters

needed to power advanced microprocessors in low

cost systems, or in distributed power applications

where efficiency is important. Internal level-shift, high-

side drive circuitry, and preset shoot-thru control, al-

lows the use of inexpensive N-channel power switches.

SC1102 features include temperature compensated

voltage reference, triangle wave oscillator and current

sense comparator circuitry. Power good signaling,

shutdown, and over voltage protection are also pro-

vided.

The SC1102 operates at a fixed 200kHz, providing an

optimum compromise between efficiency, external

component size, and cost.

FEATURES

APPLICATIONS

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

DEVICE

(1)

PACKAGE

TEMP. RANGE (T

SC1102CSTR

SO-14

0 - 125°C

SC1102EVB

Evaluation Board

ORDERING INFORMATION

Note:

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

contains 2500 devices.

APPLICATION CIRCUIT

Figure 1.

Typical Distributed Power Supply

VCC

1

PWRGD

2

OVP

3

OCSET

4

PHASE

5

DRVH

6

PGND

7

DRVL

8

BSTL

9

BSTH

10

SENSE

11

VREF

12

SS/SHDN

13

GND

14

U1

SC1102

Q1

STP40NE

Q2

STP40NE

R5

3.9

L1

2uH

C9

180/4V

C10

180/4V

C11

180/4V

C12

180/4V

C7

680/6.3V

C6

680/6.3V

R1

1k

R3

1k

C2

0.1

C3

0.1

C1

0.1

R2

PWRGD

OVP

SHDN

VREF

+

_

+

_

Vin 5V

Vout=2.5V*

R7

127

R8

124*

NOTE:

*) Vout = 1.265 x (1+R8/R7)

+5V

D1

MBR0520

R6

2.2

C4

1.0

C5

10.0

C8

680/6.3V

R4

10

+12V

C13

180/4V