TLH8821

May 1989

LM2984C Microprocessor Power Supply System

General Description

The LM2984C positive voltage regulator features three in-

dependent and tracking outputs capable of delivering the

power for logic circuits peripheral sensors and standby

memory in a typical microprocessor system The LM2984C

includes circuitry which monitors both its own high-current

output and also an external mP If any error conditions are

sensed in either a reset error flag is set and maintained until

the malfunction terminates Since these functions are in-

cluded in the same package with the three regulators a

great saving in board space can be realized in the typical

microprocessor system The LM2984C also features very

low dropout voltages on each of its three regulator outputs

(06V at the rated output current) Furthermore the quies-

cent current can be reduced to 1 mA in the standby mode

Designed also for vehicular applications the LM2984C and

all regulated circuitry are protected from reverse battery in-

stallations or 2-battery jumps Familiar regulator features

such as short circuit and thermal overload protection are

also provided Fixed outputs of 5V are available in the plas-

tic TO-220 power package

Features

Y

Three low dropout tracking regulators

Y

Output current in excess of 500 mA

Y

Low quiescent current standby regulator

Y

Microprocessor malfunction RESET flag

Y

Delayed RESET on power-up

Y

Accurate pretrimmed 5V outputs

Y

Reverse battery protection

Y

Overvoltage protection

Y

Reverse transient protection

Y

Short circuit protection

Y

Internal thermal overload protection

Y

ONOFF switch for high current outputs

Y

100% electrical burn-in in thermal limit

Typical Application Circuit

LM2984C

TLH8821 – 1

Order Number LM2984CT

See NS Package Number TA11B

maintain stability May be increased

without bound to maintain regulation

during transients Locate as close as

possible to the regulator This capac-

itor must be rated over the same op-

erating temperature range as the

regulator The equivalent series re-

sistance (ESR) of this capacitor is

critical see curve

C1995 National Semiconductor Corporation

RRD-B30M115Printed in U S A