LP2956/LP2956A

Dual Micropower Low-Dropout Voltage Regulators

General Description

The LP2956 is a micropower voltage regulator with very low

quiescent current (170 µA typical at light loads) and very low

dropout voltage (typically 60 mV at 1 mA load current and

470 mV at 250 mA load current on the main output).

The LP2956 retains all the desirable characteristics of the

LP2951, but offers increased output current (main output),

an auxiliary LDO adjustable regulated output (75 mA), and

additional features.

The auxiliary output is always on (regardless of main output

status), so it can be used to power memory circuits.

Quiescent current increases only slightly at dropout, which

prolongs battery life.

The error flag goes low if the main output voltage drops out

of regulation.

An open-collector auxiliary comparator is included, whose in-

verting input is tied to the 1.23V reference.

Reverse battery protection is provided.

The parts are available in DIP and surface mount packages.

Features

n Output voltage adjusts from 1.23V to 29V

n Guaranteed 250 mA current (main output)

n Auxiliary LDO (75 mA) adjustable output

n Auxiliary comparator with open-collector output

n Shutdown pin for main output

n Extremely low quiescent current

n Low dropout voltage

n Extremely tight line and load regulation

n Very low temperature coefficient

n Current and thermal limiting

n Reverse battery protection

Applications

n High-efficiency linear regulator

n Low dropout battery-powered regulator

Block Diagram

LP2956

DS011339-1

May 1999

© 1999 National Semiconductor Corporation

DS011339

www.national.com