LM3475

Hysteretic PFET Buck Controller

General Description

The LM3475 is a hysteretic P-FET buck controller designed

to support a wide range of high efficiency applications in a

very small SOT23-5 package. The hysteretic control scheme

has several advantages, including simple system design

with no external compensation, stable operation with a wide

range of components, and extremely fast transient re-

sponse. Hysteretic control also provides high efficiency op-

eration, even at light loads. The PFET architecture allows for

low component count as well as 100% duty cycle and ultra-

low dropout operation.

Features

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Easy to use control methodology

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0.8V to V

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High Efficiency (90% typical)

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100% duty cycle capable

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Maximum operating frequency up to 2MHz

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Internal Soft-Start

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Enable pin

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SOT23-5 package

Applications

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TFT Monitor

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Auto PC

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Vehicle Security

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Navigation Systems

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Notebook Standby Supply

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Battery Powered Portable Applications

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Distributed Power Systems

Typical Application Circuit

20070101

October 2004

© 2004 National Semiconductor Corporation

DS200701

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