Preliminary Technical Data

ADP3089

a

REV. PrE

8/26/02

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

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

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

otherwise under any patent or patent rights of Analog Devices.

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Tel: 781/329-4700

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Fax: 781/326-8703

Analog Devices, Inc., 2002

1 MHz, 1 A Buck Regulator

PRELIMINARY TECHNICAL DATA

FEATURES

1 MHz PWM Frequency

Ultrasmall 8-lead 3

×3 Sq. mm Chip Scale Package

Automatic PWM to Power Saving Mode at Light Load

Fully Integrated 1.5 A Power Switch

3% Output Regulation Accuracy over Temperature,

Line, and Load

100% Duty Cycle Operation

Simple Compensation

Output Voltage: 1.25 V to 10 V

Small Inductor and MLC Capacitors

Low Quiescent Current while Pulse Skipping

Thermal Shutdown

Fully Integrated Soft Start

Cycle-by-cycle Current Limit

APPLICATONS

PDAs and Palmtop Computers

Notebook Computers

PCMCIA Cards

Bus Products

Portable Instruments

Industrial Systems

GENERAL DESCRIPTION

The ADP3089 is a high frequency, non-synchronous PWM

step-down DC-DC regulator with an integrated 1.5 A

power switch in a space-saving chip scale package. It pro-

vides high efficiency, excellent dynamic response, and is

very simple to use.

The ADP3089’s 1 MHz switching frequency allows for

small, inexpensive external components, and the current

mode control loop is simple to compensate and eases noise

filtering. It operates in PWM current mode under heavy

loads and saves energy at lighter loads by switching auto-

matically into Power Saving mode. Soft start is integrated

completely on chip, as is the cycle-by-cycle current limit.

Capable of operating from 2.5 V to 11 V input with a

typical output current of 1 A, it is ideal for portable, bat-

tery powered, industrial, PC and instrumentation applica-

tions. Supporting output voltages down to 1.25 V, the

ADP3089 is ideal to generate low voltage rails, providing

the optimal solution in its class for delivering power effi-

ciently, responsively, and simply with minimal printed

circuit board area.

The device is specified over the industrial temperature

range of -40°C to +85°C, and is offered in an ultrasmall 8-

lead 3

×3 square mm chip scale package.

FUNCTIONAL BLOCK DIAGRAM

Figure 1. Typical Application

SW

FB

COMP

GND

IN

DRV

CURRENT

SENSE

AMP

PWM

COMPARATOR

REF

1.245V

ERROR

AMP

gm

SOFT-START

TIMER

+

R

SQ

RUN/STOP

COMPARATORS

1MHz

PROTECTION

LOGIC

(ILIM, OT)

IN

GND

SW

GND

FB

IN

GND

COMP

ADP3089

VOUT

1.8V@1A

10

µH

18.2k

Ω

41.2k

Ω

10.7k

Ω

470pF

20BQ030

IN

DRV

VIN

22µF

0.1µF

10µF

47pF