LP3999

Low Noise 150mA Voltage Regulator for RF/Analog

Applications

General Description

The LP3999 regulator is designed to meet the requirements

of portable wireless battery-powered applications and will

provide an accurate output voltage with low noise and low

quiescent current. Ideally suited for powering RF/Analog

devices this device will also be used to meet more general

circuit requirements.

For battery powered applications the low dropout and low

ground current provided by the device allows the lifetime of

the battery to be maximized.The inclusion of an Enable(dis-

able) control can be used by the system to further extend the

battery lifetime by reducing the power consumption to virtu-

ally zero. Should the application require a device with an

active disable function please refer to device LP3995.

The LP3999 also features internal protection against short-

circuit currents and over-temperature conditions.

The LP3999 is designed to be stable with small 1.0 µF

ceramic capacitors. The small outline of the LP3999 micro

SMD package with the required ceramic capacitors can

realize a system application within minimal board area.

Performance is specified for a −40˚C to +125˚C temperature

range.

The device is available in micro SMD package. For other

package options contact your local NSC sales office.

The device is available in fixed output voltages in the ranges

of 1.5V to 3.3V. For availability, please contact your local

NSC sales office.

Key Specifications

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2.5V to 6.0V Input Range

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60 mV Typical Dropout with 150 mA Load. V

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Virtually Zero Quiescent Current when Disabled

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10 µVrms output noise over 10Hz to 100kHz

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Stable witha1µF Output Capacitor

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Guaranteed 150 mA Output Current

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Fast Turn-on Time; 140 µs (Typ.)

Features

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5 pin micro SMD Package

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Stable with Ceramic Capacitor

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Logic Controlled Enable

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Fast Turn-on

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Thermal-overload and short-circuit protection

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

Applications

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GSM Portable Phones

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CDMA Cellular Handsets

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Wideband CDMA Cellular Handsets

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Bluetooth Devices

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Portable Information Appliances

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Handheld MP3 Devices

Typical Application Circuit

20052001

November 2005

© 2005 National Semiconductor Corporation

DS200520

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