LM2984

Microprocessor Power Supply System

General Description

The LM2984 positive voltage regulator features three inde-

pendent and tracking outputs capable of delivering the

power for logic circuits, peripheral sensors and standby

memory in a typical microprocessor system. The LM2984 in-

cludes circuitry which monitors both its own high-current out-

put and also an external µP. 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 mi-

croprocessor system. The LM2984 also features very low

dropout voltages on each of its three regulator outputs (0.6V

at the rated output current). Furthermore, the quiescent cur-

rent can be reduced to 1 mA in the standby mode.

Designed also for vehicular applications, the LM2984 and all

regulated circuitry are protected from reverse battery instal-

lations or 2-battery jumps. Familiar regulator features such

as short circuit and thermal overload protection are also pro-

vided. Fixed outputs of 5V are available in the plastic TO-220

power package.

Features

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Three low dropout tracking regulators

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Output current in excess of 500 mA

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Fully specified for −40˚C to +125˚C operation

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Low quiescent current standby regulator

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Microprocessor malfunction RESET flag

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Delayed RESET on power-up

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Accurate pretrimmed 5V outputs

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Reverse battery protection

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Overvoltage protection

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Reverse transient protection

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Short circuit protection

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Internal thermal overload protection

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ON/OFF switch for high current outputs

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P

Typical Application Circuit

DS011252-1

the regulator. This capacitor must be rated over the same operating temperature range as the regulator. The equivalent series resistance (ESR) of this

capacitor is critical; see curve.

Order Number LM2984T

See NS Package Number TA11B

April 1998

© 1998 National Semiconductor Corporation

DS011252

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