LP3905

Power Management Unit For Low Power Handheld

Applications

General Description

LP3905 is a multi-functional Power Management Unit,

optimized for low power handheld applications. This device

integrates two 600mA DC/DC buck regulators and two

150mA linear regulators. Fixed and adjustable buck output

versions are available. The LP3905 additionally features two

enable pins for the device output control and is offered in an

LLP package.

Features

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Two buck regulators for powering high current processor

functions or peripheral devices

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Two linear regulators for powering internal processor

functions and I/Os

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One enable pin for Buck1 and Linear Regulators1&2

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Separate enable pin for Buck2

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Thermal and current overload protection

n

Small 14–Pin LLP package (4mm x 4mm x 0.8mm)

Applications

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Baseband Processors

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Peripheral Processor (Video, Audio)

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I/O Power

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FPGA Power

Key Specifications

Buck Regulators

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Fixed and adjustable voltage options, range 1.0V to

3.3V *

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Up to 90% Efficiency

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Auto-switching PFM-PWM mode and fixed PWM mode

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2MHz PWM fixed switching frequency (Typ)

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600mA output current

4% output voltage accuracy over temp.

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Internal softstart

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2.2µH inductor, 10µF Input and 10µF output Caps

Linear Regulators

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Output options in the range 1.5V to 3.3V *

n

13.5µV

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3% output voltage accuracy over full line and load

regulation

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0mA to 150mA output current

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C

C

80mV Dropout voltage

* Fixed output voltage devices can be customized to fit

system requirements. Please contact National Semiconduc-

tor Sales Office.

Typical Application Circuit

20152901

FIGURE 1. Typical Application Circuit – 14 Pin LLP Package

August 2006

© 2006 National Semiconductor Corporation

DS201529

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