LP3470 Tiny Power On Reset Circuit
June 1999
LP3470
Tiny Power On Reset Circuit
General Description
The LP3470 is a micropower CMOS voltage supervisory cir-
cuit designed to monitor power supplies in microprocessor
(碌P) 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 volt-
age (V
RTH
) options: 2.63V, 2.93V, 3.08V, 4.00V, 4.38V, and
4.63V. If other voltage options between 2.4V and 5.0V are
desired please contact your National Semiconductor repre-
sentative.
The LP3470 asserts a reset signal whenever the V
CC
supply
voltage falls below a reset threshold. The reset time-out pe-
riod is adjustable using an external capacitor. Reset remains
asserted for an interval (programmed by an external capaci-
tor) after V
CC
has risen above the threshold voltage.
The device is available in the tiny SOT23-5 package.
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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 碌A(chǔ) typical)
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Guaranteed Reset valid down to V
CC
=0.5V
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
CC
Transients
Applications
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n
n
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Critical 碌P and 碌C Power Monitoring
Intelligent Instruments
Computers
Portable/Battery-Powered Equipments
Key Specifications
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鹵
1% Reset Threshold Accuracy Over Temperature
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Standard Reset Threshold Voltages: 2.63V, 2.93V,
3.08V, 4.00V, 4.38V, and 4.63V
Pin Configuration and Basic Operating Circuit
Pin Configuration
Basic Operating Circuit
DS100016-2
Top View
See NS Package Number
MA05B
DS100016-1
漏 1999 National Semiconductor Corporation
DS100016
www.national.com