LP3470

Tiny Power On Reset Circuit

General Description

The LP3470 is a micropower CMOS voltage supervisory

circuit designed to monitor power supplies in microprocessor

(µP) and other digital systems. It provides maximum adjust-

ability for power-on-reset (POR) and supervisory functions. It

is available in the following six standard reset threshold

voltage (V

4.38V, and 4.63V. If other voltage options between 2.4V and

5.0V are desired please contact your National Semiconduc-

tor representative.

The LP3470 asserts a reset signal whenever the V

voltage falls below a reset threshold. The reset time-out

period is adjustable using an external capacitor. Reset re-

mains asserted for an interval (programmed by an external

capacitor) after V

The device is available in the tiny SOT23-5 package.

Key Specifications

1% Reset Threshold Accuracy Over Temperature

n

Standard Reset Threshold Voltages: 2.63V, 2.93V,

3.08V, 3.65V, 4.00V, 4.38V, and 4.63V

n

Custom Reset Threshold Voltages: For other voltages

between 2.4V and 5.0V contact your National

Semiconductor representative

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Very Low Quiescent Current (16 µA typical)

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Guaranteed Reset valid down to V

Features

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Tiny SOT23-5 Package

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Open Drain Reset Output

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Programmable Reset Timeout Period Using an External

Capacitor

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Immune to Short V

Applications

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Critical µP and µC Power Monitoring

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Intelligent Instruments

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Computers

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Portable/Battery-Powered Equipments

Pin Configuration and Basic Operating Circuit

Pin Configuration

Basic Operating Circuit

10001602

Top View

See NS Package Number

MF05A

10001601

September 2000

© 2004 National Semiconductor Corporation

DS100016

www.national.com