LM2698

General Description

The LM2698 is a general purpose PWM boost converter.

The 1.9A, 18V, 0.2ohm internal switch enables the LM2698

to provide efficient power conversion to outputs ranging from

2.2V to 17V. It can operate with input voltages as low as 2.2V

and as high as 12V. Current-mode architecture provides

superior line and load regulation and simple frequency com-

pensation over the device’s 2.2V to 12V input voltage range.

The LM2698 sets the standard in power density and is

capable of supplying 12V at 400mA from a 5V input. The

LM2698 can also be used in flyback or SEPIC topologies.

switching frequency of either 600kHz or 1.25MHz. This pro-

motes flexibility in component selection and filtering tech-

niques. A shutdown pin is available to suspend the device

and decrease the quiescent current to 5µA. An external

compensation pin gives the user flexibility in setting fre-

quency compensation, which makes possible the use of

small, low ESR ceramic capacitors at the output. Switchers

and guaranteed design. The LM2698 is available in a low

profile 8-lead MSOP package.

Features

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1.9A, 0.2

Ω, internal switch (typical)

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Operating voltage as low as 2.2V

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600kHz/1.25MHz adjustable frequency operation

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8-Lead MSOP package

Applications

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3.3V to 5V, 5V to 12V conversion

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Distributed Power

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Set-Top Boxes

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DSL Modems

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Diagnostic Medical Instrumentation

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Boost Converters

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Flyback Converters

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SEPIC Converters

Typical Application Circuit

20012658

October 2001

© 2001 National Semiconductor Corporation

DS200126

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