REV. 0

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a

ADP1110

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

Tel: 617/329-4700

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

Fax: 617/326-8703

© Analog Devices, Inc., 1996

Micropower, Step-Up/Step-Down Switching

Regulator; Adjustable and Fixed 3.3 V, 5 V, 12 V

FUNCTIONAL BLOCK DIAGRAMS

SENSE

A0

DRIVER

SW1

SW2

SET

220mV

REFERENCE

GAIN BLOCK/

ERROR AMP

A2

A1

Q1

OSCILLATOR

ADP1110

GND

COMPARATOR

R1

R2

300k

Ω

ADP1110 Block Diagram—Fixed Output Version

A0

DRIVER

SW1

SW2

GND

SET

220mV

REFERENCE

GAIN BLOCK/

ERROR AMP

COMPARATOR

FB

A2

A1

Q1

OSCILLATOR

ADP1110

ADP1110 Block Diagram—Adjustable Output Version

FEATURES

Operates at Supply Voltages From 1.0 V to 30 V

Step-Up or Step-Down Mode

Minimal External Components Required

Low-Battery Detector

User-Adjustable Current Limiting

Fixed or Adjustable Output Voltage Versions

8-Pin DIP or SO-8 Package

APPLICATIONS

Cellular Telephones

Single-Cell to 5 V Converters

Laptop and Palmtop Computers

Pagers

Cameras

Battery Backup Supplies

Portable Instruments

Laser Diode Drivers

Hand-Held Inventory Computers

GENERAL DESCRIPTION

The ADP1110 is part of a family of step-up/step-down switch-

ing regulators that operate from an input voltage supply as little

as 1.0 V. This very low input voltage allows the ADP1110 to be

used in applications that use a single cell as the primary power

source.

The ADP1110 can be configured to operate in either step-up or

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

ADP1111 would be a more effective solution.

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

as a linear regulator.

The quiescent current of 300

µA makes the ADP1110 useful in

remote or battery powered applications.

The 70 kHz frequency operation also allows for the use of

surface-mount external capacitors and inductors.

Battery protection circuitry limits the effect of reverse current to

safe levels at reverse voltages up to 1.6 V.