LP3981

Micropower, 300mA Ultra Low-Dropout CMOS Voltage

Regulator

General Description

The LP3981’s performance is optimized for battery powered

systems to deliver ultra low noise, extremely low dropout

voltage and low quiescent current. Regulator ground current

increases only slightly in dropout, further prolonging the

battery life.

Power supply rejection is better than 60 dB at low frequen-

cies. This high power supply rejection is maintained down to

lower input voltage levels common to battery operated cir-

cuits.

The device is ideal for mobile phone and similar battery

powered wireless applications. It provides up to 300 mA,

from a 2.5V to 6V input, consuming less than 1µA in disable

mode.

The LP3981 is available in MSOP-8 package. For LP3981 in

LLP-6 package, contact NSC sales offices. Performance is

specified for −40˚C to +125˚C temperature range. The de-

vice available in the following output voltages; 2.5V, 2.7V,

2.8V, 2.83V, 3.0V, 3.03V and 3.3V as standard. Other output

options can be made available, please contact your local

NSC sales office.

Key Specifications

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2.5 to 6.0V input range

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300mA guaranteed output

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60dB PSRR at 1kHz

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≤1µA quiescent current when shut down

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Fast Turn-On time: 120 µs (typ.) with C

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132mV typ dropout with 300mA load

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35µVrms output noise over 10Hz to 100kHz

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

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2.5V, 2.7V, 2.8V, 2.83V, 3.0V, 3.03V, and 3.3V outputs

standard

Features

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Small, space saving MSOP-8

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Low Thermal Resistance in LLP-6 package gives

excellent power capability

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Logic controlled enable

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Stable with ceramic and high quality tantalum capacitors

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Fast turn-on

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Thermal shutdown and short-circuit current limit

Applications

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CDMA cellular handsets

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Wideband CDMA cellular handsets

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GSM cellular handsets

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Portable information appliances

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Typical Application Circuit

20020302

Note: Pin Numbers in parenthesis indicate LLP-6 package.

March 2003

© 2003 National Semiconductor Corporation

DS200203

www.national.com