REV. 0

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

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a

ADP1073

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., 1997

Micropower DC–DC Converter

Adjustable and Fixed 3.3 V, 5 V, 12 V

FUNCTIONAL BLOCK DIAGRAMS

SET

GAIN BLOCK/

ERROR AMP

COMPARATOR

SW2

FB

GND

SW1

AO

OSCILLATOR

DRIVER

A1

A2

212mV

REFERENCE

ADP1073

ADP1073

SET

GAIN BLOCK/

ERROR AMP

COMPARATOR

SW2

SENSE

GND

SW1

AO

OSCILLATOR

DRIVER

A1

A2

212mV

REFERENCE

ADP1073-3.3

ADP1073-5

ADP1073-12

R2

904k

R1

ADP1073-3.3: R1 = 62.1k

ADP1073-5: R1 = 40k

ADP1073-12: R1 = 16.3k

ADP1073-3.3, 5, 12

FEATURES

Operates at Supply Voltages from 1.0 V to 30 V

Ground Current 100

A

Works in Step-Up or Step-Down Mode

Very Few External Components Required

Low Battery Detector On-Chip

User-Adjustable Current Limit

Internal 1 A Power Switch

Fixed and Adjustable Output Voltage Versions

8-Lead DIP or SO-8 Package

APPLICATIONS

Single-Cell to 5 V Converters

Laptop and Palmtop Computers

Pagers

Cameras

Battery Backup Supplies

Cellular Telephones

Portable Instruments

4 mA–20 mA Loop Powered Instruments

Hand-Held Inventory Computers

GENERAL DESCRIPTION

The ADP1073 is part of a family of step-up/step-down switch-

ing regulators that operates from an input supply voltage of as

little as 1.0 V. This extremely low input voltage allows the

ADP1073 to be used in applications requiring use of a single

cell battery as the primary power source.

The ADP1073 can be configured to operate in either step-up or

step-down mode but for input voltages greater than 3 V, the

ADP1173 is recommended.

An auxiliary gain amplifier can serve as a low battery detector or

linear regulator. Quiescent current on the ADP1073-5 is only

100

µA unloaded, making it ideal for systems where long battery

life is required.

The ADP1073 can deliver 40 mA at 5 V from an input voltage

range as low as 1.25 V, or 10 mA at 5 V from a 1.0 V input.

Current limiting is available by adding an external resistor.