LM2640

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SNVS019B – DECEMBER 1998 – REVISED APRIL 2013

LM2640 Dual Adjustable Step-Down Switching Power Supply Controller

Check for Samples: LM2640

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FEATURES

DESCRIPTION

The LM2640 is a dual step-down power supply

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•

200 kHz Fixed-Frequency Switching

controller

intended

for

application

in

notebook

•

Switching Synchronization with an External

personal

computers

and

other

battery-powered

Signal up to 400 kHz

equipment.

•

Optional Pulse-Skipping Mode

Fixed-frequency synchronous drive of logic-level N-

•

Adjustable Secondary Feedback

channel power MOSFETs is combined with an

optional pulse-skipping mode to achieve ultra efficient

•

Input Undervoltage Lockout

power conversion over a 1000:1 load current range.

•

Output Undervoltage Shutdown Protection

The pulse-skipping mode can be disabled in favor of

•

Output Overvoltage Shutdown Protection

fixed-frequency operation regardless of the load

•

Programmable Soft-Start (Each Controller)

current level.

•

5V, 50 mA Linear Regulator Output

High DC gain and current-mode feedback control

assure excellent line and load regulation and a wide

•

Precision 2.5V Reference Output

loop bandwidth for fast response to dynamic loads.

•

28-Pin Package

An internal oscillator fixes the switching frequency at

APPLICATIONS

200 kHz. Optionally, switching can be synchronized

to an external clock running as fast as 400 kHz.

•

Notebook and Subnotebook Computers

An optional soft-start feature limits current surges

•

Wireless Data Terminals

from the input power supply at start up and provides

•

Battery-Powered Instruments

a simple means of start-up sequencing.

Logic-level inputs allow the controllers to be turned

KEY SPECIFICATIONS

ON and OFF separately.

•

96% Efficient

•

5.5V to 30V Input Range

•

Dual Outputs Adjustable from 2.2V to 6V

•

0.5% Typical Load Regulation Error

•

0.002%/V Typical Line Regulation Error

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PRODUCTION DATA information is current as of publication date.

Copyright © 1998–2013, Texas Instruments Incorporated

Products conform to specifications per the terms of the Texas

Instruments standard warranty. Production processing does not

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