LP3853/LP3856

3A Fast Response Ultra Low Dropout Linear Regulators

General Description

The LP3853/LP3856 series of fast ultra low-dropout linear

regulators operate from a +2.5V to +7.0V input supply. Wide

range of preset output voltage options are available. These

ultra low dropout linear regulators respond very quickly to

step changes in load, which makes them suitable for low

voltage microprocessor applications. The LP3853/LP3856

are developed on a CMOS process which allows low quies-

cent current operation independent of output load current.

This CMOS process also allows the LP3853/LP3856 to op-

erate under extremely low dropout conditions.

Dropout Voltage: Ultra low dropout voltage; typically 39mV

at 300mA load current and 390mV at 3A load current.

Ground Pin Current: Typically 4mA at 3A load current.

Shutdown Mode: Typically 10nA quiescent current when

the shutdown pin is pulled low.

Error Flag: Error flag goes low when the output voltage

drops 10% below nominal value.

SENSE: Sense pin improves regulation at remote loads.

Precision Output Voltage: Multiple output voltage options

are available ranging from 1.8V to 5.0V with a guaranteed

conditions (varying line, load, and temperature).

Features

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Ultra low dropout voltage

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Stable with selected ceramic capacitors

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Low ground pin current

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Load regulation of 0.08%

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10nA quiescent current in shutdown mode

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Guaranteed output current of 3A DC

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Available in TO-263 and TO-220 packages

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Error flag indicates output status

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Sense option improves load regulation

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Overtemperature/overcurrent protection

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−40˚C to +125˚C junction temperature range

Applications

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Microprocessor power supplies

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Stable with ceramic output capacitors

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GTL, GTL+, BTL, and SSTL bus terminators

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Power supplies for DSPs

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SCSI terminator

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Post regulators

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High efficiency linear regulators

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Battery chargers

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Other battery powered applications

Typical Application Circuits

20030901

**SD and ERROR pins must be pulled high through a 10k

Ω pull-up resistor. Connect the ERROR pin to ground if this function is not used. See Application Hints

for more information.

March 2004

© 2004 National Semiconductor Corporation

DS200309

www.national.com