LM9074

System Voltage Regulator with Keep-Alive ON/OFF

Control

General Description

The LM9074 is a 5V, 3% accurate, 180 mA NPN voltage

regulator. The regulator features an active low delayed reset

output flag which can be used to reset a microprocessor sys-

tem on turn-ON and in the event that the regulator output

falls out of regulation for any reason. An external capacitor

programs a delay time interval before the reset output can

return high.

Designed for automotive application the LM9074 contains a

variety of protection features such as reverse battery,

over-voltage shutdown, thermal shutdown, input transient

protection and a wide operating temperature range.

A unique two-input logic control scheme is used to enable or

disable the regulator output. An ON/OFF input can be pro-

vided by an ignition switch derived signal while a second,

Keep-Alive input, is generated by a system controller. This

allows for a system to remain ON after ignition has been

switched OFF. The system controller can then execute a

power-down routine and after which command the regulator

OFF to a low quiescent current state (60 µA max).

Design techniques have been employed to allow the regula-

tor to remain operational and not generate false reset signals

when subjected to high levels of RF energy (300V/m from

2 MHz to 400 MHz).

Features

n

Automotive application reliability

n

3% output voltage tolerance

n

Insensitive to radiated RFI

n

Dropout voltage less than 2.5V with 180 mA output

current

n

Externally programmed reset delay interval

n

Keep-alive feature with 2 logic control inputs

n

60V Load dump transient protection

n

Thermal shutdown

n

Short circuit protection and disable safety features

n

Reverse battery protection

n

Low OFF quiescent current, 60 µA maximum

n

Wide operating temperature range −40˚C to +125˚C

14-Pin SO Package

DS101305-2

Order Number LM9074M

See NS Package Number M14A

PRELIMINARY

January 2000

© 2000 National Semiconductor Corporation

DS101305

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