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a

ADP3152

One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.

Tel: 781/329-4700

World Wide Web Site: http://www.analog.com

Fax: 781/326-8703

© Analog Devices, Inc., 1998

5-Bit Programmable Synchronous

Switching Regulator Controller

FEATURES

5-Bit Digitally Programmable 1.8 V to 3.5 V Output

Voltage

Dual N-Channel Synchronous Driver

Total Output Accuracy

1% (0 C to 70 C)

High Efficiency

Current-Mode Operation

Short Circuit Protection

Power Good Output

Integrated Overvoltage Protection Crowbar

16-Lead SOIC Package

VRM 8.2 Compatible

APPLICATIONS

Desktop PC Power Supply for:

Pentium II Processor

Pentium Pro Processor

Pentium Processor

AMD–K6 Processor

VRM Modules

GENERAL DESCRIPTION

The ADP3152 is a highly efficient synchronous switching regu-

lator controller optimized for Pentium II Processor applications

where 5 V is stepped down to a digitally controlled output volt-

age between 1.8 V and 3.5 V. Using a 5-bit DAC to read a

voltage identification (VID) code directly from the processor,

the ADP3152 uses a current mode constant off-time architec-

ture to generate its precise output voltage.

The ADP3152 drives two N-channel MOSFETS in a synchro-

nous rectified buck converter, at a maximum switching fre-

quency of 250 kHz. Using the recommended loop compensation

and guidelines, the ADP3152 provides a dc/dc converter that

meets Intel’s stringent transient specifications with a minimum

number of output capacitors and smallest footprint. Additionally,

the current mode architecture also provides guaranteed short

circuit protection and adjustable current limiting.

SD

DRIVE1

SENSE+

SENSE–

DRIVE2

PGND

VID0–VID4

AGND

CMP

+12V

1 F

22 F

R1

R2

150pF

5-BIT CODE

IRL3103

+5V

+

10BQ015

L

2.5 H

IRL3103

+

1.8V–3.5V

14A

6.7m

1nF

ADP3152

Figure 1. Typical Application

Pentium is a registered trademark of Intel Corporation.

All other trademarks are the property of their respective holders.