PROGRAMMABLE SYNCHRONOUS DC/DC

CONVERTER, DUAL LOW DROPOUT

REGULATOR CONTROLLER

© 1999 SEMTECH CORP.

PRELIMINARY - December 2, 1999

652 MITCHELL ROAD NEWBURY PARK CA 91320

SC1186

1

DESCRIPTION

The SC1186 combines a synchronous voltage mode

controller with two low-dropout linear regulators

providing most of the circuitry necessary to

implement three DC/DC converters for powering

advanced microprocessors such as Pentium

The SC1186 switching section features an integrated

5 bit D/A converter, latched drive output for

enhanced noise immunity, pulse by pulse current

limiting and logic compatible shutdown. The SC1186

switching section operates at a fixed frequency of

140kHz, providing an optimum compromise between

size, efficiency and cost in the intended application

areas. The integrated D/A converter provides

programmability of output voltage from 2.0V to 3.5V

in 100mV increments and 1.30V to 2.05V in 50mV

increments with no external components.

The SC1186 linear sections are low dropout regula-

tors with short circuit protection, supplying 1.5V for

GTL bus and 2.5V for non-GTL I/O. The Reference

voltage is made available for external linear

regulators.

Pentium is a registered trademark of Intel Corporation

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

BLOCK DIAGRAM

R

S

Q

+

-

70mV

+

-

+

-

2.5V FET

CONTROLLER

1.5V FET

CONTROLLER

1.265V

REF

ERROR

AMP

D/A

SHOOT-THRU

CONTROL

VCC

CS-

BSTH

DH

PGNDH

EN

CS+

BSTL

DL

PGNDL

VOSENSE

LDOEN

LDOS2

VID3

LDOS1

VID2

VID1

VID0

AGND

REF

GATE2

GATE1

LDOV

REF

VID4

CURRENT

LIMIT

LEVEL SHIFT AND

HIGH SIDE DRIVE

SYNCHRONOUS

MOSFET DRIVE

OSCILLATOR

PIN CONFIGURATION

AGND

GATE1

LDOS1

LDOS2

VCC

REF

LDOEN

CS-

CS+

PGNDH

DH

PGNDL

1

2

3

LDOV

4

5

6

7

8

9

10

11

12

24

23

22

21

20

19

18

17

16

15

14

13

VOSENSE

EN

BSTH

BSTL

DL

VID0

VID1

VID2

VID3

VID4

GATE2

Top View

(24 Pin SOIC)

FEATURES

APPLICATIONS

ORDERING INFORMATION

Part Number

(1)

Package

Linear

Voltage

Temp.

Range (T

SC1186CSW

SO-24

1.5V/2.5V 0° to 125°C

Note:

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