LM3557

R2

L

2.2 PH

Cin

4.7 PF

Cout

1 PF

NC

En

Gnd

Fb

Sw2

Ovp

Sw1

D

Vout

LM3557

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SNVS338B – NOVEMBER 2004 – REVISED FEBRUARY 2013

LM3557 Step-Up Converter for White LED Applications

Check for Samples: LM3557

1

FEATURES

DESCRIPTION

The LM3557 is a complete solution for white LED

2

•

drive applications. With minimal external component

•

Small External Components

count, no DC current leakage paths to ground, cycle-

•

1.25 MHz Constant-Switching Frequency

by-cycle current limit protection, and output over-

voltage protection circuitry, the LM3557 offer superior

•

Output Over-Voltage Protection

performance and cost savings over standard DC/DC

•

Input Under-Voltage Protection

boost component implementations.

•

Cycle-By-Cycle Current Limit

The LM3557 switches at a fixed-frequency of 1.25

•

TRUE SHUTDOWN: No DC current paths to

MHz, which allows for the use of small external

ground during shutdown

components. Also, the LM3557 has a wide input

•

Low Profile Package: <1 mm Height -8 Pin

voltage range to take advantage of multi-cell input

applications. With small external components, high

WSON

fixed frequency operation, and wide input voltage

•

No External Compensation

range, the LM3557 is the most optimal choice for

LED lighting applications.

APPLICATIONS

•

White LED Display Lighting

•

Cellular Phones

•

PDAs

Typical Application Circuit

Figure 1. Backlight Configuration

1

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Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.

2

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PRODUCTION DATA information is current as of publication date.

Copyright © 2004–2013, Texas Instruments Incorporated

Products conform to specifications per the terms of the Texas

Instruments standard warranty. Production processing does not

necessarily include testing of all parameters.