LP2957/LP2957A

5V Low-Dropout Regulator for µP Applications

General Description

The LP2957 is a 5V micropower voltage regulator with elec-

tronic shutdown, error flag, very low quiescent current

(150 µA typical at 1 mA load), and very low dropout voltage

(470 mV typical at 250 mA load current).

Output can be wired for snap-on/snap-off operation to elimi-

nate transition voltage states where µP operation may be un-

predictable.

Output crowbar (50 mA typical pull-down current) will bring

down the output quickly when the regulator snaps off or

when the shutdown function is activated.

The part has tight line and load regulation (0.04% typical)

and low output temperature coefficient (20 ppm/˚C typical).

The accuracy of the 5V output is guaranteed at room tem-

perature and over the full operating temperature range.

The LP2957 is available in the five-lead TO-220 and TO-263

packages.

Features

n 5V output within 1.4% over temperature (A grade)

n Easily programmed for snap-on/snap-off output

n Guaranteed 250 mA output current

n Extremely low quiescent current

n Low Input-Output voltage required for regulation

n Reverse battery protection

n Extremely tight line and load regulation

n Very low temperature coefficient

n Current and thermal limiting

n Error flag signals when output is out of regulation

Applications

n High-efficiency linear regulator

n Battery-powered regulator

Package Outline

Bent, Staggered Leads

5-Lead TO-220 (T)

DS011340-16

Top View

Order Number LP2957AIT or LP2957IT

See NS Package Number T05D

Plastic Surface Mount Package

5-Lead TO-263 (S)

DS011340-17

Top View

DS011340-18

Side View

Order Number LP2957AIS or LP2957IS

See NS Package Number TS5B

June 1998

© 1999 National Semiconductor Corporation

DS011340

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