REV. A

Information furnished by Analog Devices is believed to be accurate and

reliable. However, no responsibility is assumed by Analog Devices for its

use, nor for any infringements of patents or other rights of third parties that

may result from its use. No license is granted by implication or otherwise

under any patent or patent rights of Analog Devices.

a

ADP3162

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

Tel: 781/329-4700

www.analog.com

Fax: 781/326-8703

© Analog Devices, Inc., 2001

5-Bit Programmable 2-Phase

Synchronous Buck Controller

FUNCTIONAL BLOCK DIAGRAM

2-PHASE

DRIVER

LOGIC

UVLO

& BIAS

3.0V

REFERENCE

OSCILLATOR

SET

RESET

CROWBAR

VCC

REF

GND

CT

COMP

PWM1

PWM2

PWRGD

CS–

CS+

FB

VID

DAC

VID3

VID2

VID1

VID0

VID25

CMP

CMP

DAC–18%

DAC+24%

ADP3162

CMP1

CMP2

CMP3

FEATURES

ADOPT™ Optimal Positioning Technology for Superior

Load Transient Response and Fewest Output

Capacitors

Complies with VRM 8.5 with Lowest System Cost

Active Current Balancing Between Both Output Phases

5-Bit Digitally Programmable 1.05 V to 1.825 V Output

Dual Logic-Level PWM Outputs for Interface to

External High-Power Drivers

Total Output Accuracy

0.8% Over Temperature

Current-Mode Operation

Short Circuit Protection

Power Good Output

Overvoltage Protection Crowbar Protects

Microprocessors with No Additional

External Components

APPLICATIONS

Desktop PC Power Supplies for:

Intel Tualatin Processors

VRM Modules

GENERAL DESCRIPTION

The ADP3162 is a highly efficient dual output synchronous

buck switching regulator controller optimized for converting a

5 V or 12 V main supply into the core supply voltage required by

high-performance processors such as Tualatin. The ADP3162

uses an internal 5-bit DAC to read a voltage identification (VID)

code directly from the processor, which is used to set the output

voltage between 1.05 V and 1.825 V. The ADP3162 uses a

current mode PWM architecture to drive two logic-level outputs

at a programmable switching frequency that can be optimized

for VRM size and efficiency. The output signals are 180 degrees

out of phase, allowing for the construction of two complementary

buck switching stages. These two stages share the dc output

current to reduce overall output voltage ripple. An active cur-

rent balancing function ensures that both phases carry equal

portions of the total load current, even under large transient

loads, to minimize the size of the inductors.

The ADP3162 also uses a unique supplemental regulation tech-

nique called active voltage positioning to enhance load transient

performance. Active voltage positioning results in a dc/dc converter

that meets the stringent output voltage specifications for high

performance processors, with the minimum number of output

capacitors and smallest footprint. Unlike voltage-mode and

standard current-mode architectures, active voltage positioning

adjusts the output voltage as a function of the load current so

that it is always optimally positioned for a system transient. The

ADP3162 also provides accurate and reliable short circuit pro-

tection and adjustable current limiting.

The ADP3162 is specified over the commercial temperature

range of 0

°C to 70°C and is available in a 16-lead narrow body

SOIC package.

ADOPT is a trademark of Analog Devices, Inc.