LM431

Adjustable Precision Zener Shunt Regulator

General Description

The LM431 is a 3-terminal adjustable shunt regulator with

guaranteed temperature stability over the entire temperature

range of operation. It is now available in a chip sized pack-

age (4-Bump micro SMD) using National’s micro SMD pack-

age technology. The output voltage may be set at any level

greater than 2.5V (V

external resistors that act as a voltage divided network. Due

to the sharp turn-on characteristics this device is an excel-

lent replacement for many zener diode applications.

Features

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Average temperature coefficient 50 ppm/˚C

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Temperature compensated for operation over the full

temperature range

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Programmable output voltage

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Fast turn-on response

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Low output noise

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LM431 in micro SMD package

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See AN-1112 for micro SMD considerations

Connection Diagrams

Note: *NC = Not internally connected. Must be electrically isolated from the

rest of the circuit for the microSMD package.

TO-92: Plastic Package

DS010055-1

Top View

SO-8: 8-Pin Surface Mount

DS010055-2

Top view

SOT-23: 3-Lead Small Outline

DS010055-28

Top View

4-Bump micro SMD

DS010055-54

Top View

(bump side down)

March 2002

© 2002 National Semiconductor Corporation

DS010055

www.national.com