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a

ADP3020

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., 2000

High-Efficiency Notebook Computer

Power Supply Controller

FUNCTIONAL BLOCK DIAGRAM

POWER-ON

RESET

LINEAR

CONTROLLER

5.5V TO 25V

3.3V

Q5

2.5V

SS3

Q1

Q2

Q3

SS5

Q4

5V

L1

L2

PWRGD

ADP3020

REF

5V LINEAR

3.3V

SMPS

5V

SMPS

1.20V

PFO

3.3V

SMPS

FEATURES

Wide Input Voltage Range: 4.5 V to 25 V

High Conversion Efficiency > 96%

Integrated Current Sense—No External Resistor Required

Low Shutdown Current: 7

A (Typical)

Dual Synchronous Buck Controllers with Selectable

PWM/Power-Saving Mode Operation

Built-In Gate Drive Boost Circuit for Driving External

N-Channel MOSFETs

Two Independently Programmable Output Voltages

Fixed 3.3 V or Adjustable (1.25 V to VIN–0.5 V)

Fixed 5 V or Adjustable (1.25 V to VIN–0.5 V)

Programmable PWM Frequency

Integrated Linear Regulator Controller

Extensive Circuit Protection Functions

38-Lead TSSOP Package

APPLICATIONS

Notebook Computers and PDAs

Portable Instruments

General Purpose DC-DC Converters

GENERAL DESCRIPTION

The ADP3020 is a highly efficient dual synchronous buck switch-

ing regulator controller optimized for converting the battery or

adapter input into the system supply voltages required in note-

book computers. The ADP3020 uses a dual-mode PWM/Power

Saving Mode architecture to maintain efficiency over a wide

load range. The oscillator frequency can be programmed for

200 kHz, 300 kHz, or 400 kHz operation, or it can be synchro-

nized to an external clock signal of up to 600 kHz.

The ADP3020 provides accurate and reliable short circuit pro-

tection using an internal current sense circuit, which reduces

cost and increases overall efficiency. Other protection features

include programmable soft-start, UVLO, and integrated output

undervoltage/overvoltage protection. The ADP3020 contains a

linear regulator controller that is designed to drive an external

P-channel MOSFET or PNP transistor. The linear regulator

output is adjustable, and can be used to generate the auxiliary

voltages required in many laptop designs.