LM3551/2

SW

FB

FET-T

FET-F

D1

L1

SS

OVP

FTO

SD/

EN

T/F

LUMILED

LXCL-PWF1

Flash LED

Sharp

GM5BW05340A

Flash LED

LM3551/2

SW

FB

FET-T

FET-F

D1

L1

SS

OVP

FTO

SD/

EN

T/F

GND

LM3551, LM3552

www.ti.com

SNVS371D – AUGUST 2005 – REVISED MAY 2013

LM3551 /LM3552 1A White LED Driver with Flash Timeout Protection

Check for Samples: LM3551, LM3552

1

FEATURES

DESCRIPTION

The LM3551 and LM3552 are fixed frequency,

2

•

Up to 1A Total Drive Current

current mode step-up DC/DC converters with two

•

Flash Timeout Protection

integrated NFETs that can be used for precision LED

•

Independent Torch/Flash/Shutdown Modes

brightness control. The devices are capable of driving

loads up to 1A from a single-cell Li-Ion battery.

•

LED Disconnect in Shutdown

•

Programmable Soft-Start Limits Inrush Current

The LM3551 and LM3552 can drive one or more high

current flash LEDs either in a high power Flash mode

•

Over-Voltage Protection

or

a

lower

power

Torch

mode

using

the

•

Wide Voltage Range 2.7 to 5.5V

TORCH/FLASH

pin.

A

programmable

Timeout

•

1.25MHz Constant Switching Frequency

function on the FTO pin forces the internal NFETs to

turn off after a certain user defined time. An external

•

Small, Low Profile Package, Non-Pullback

SD pin (LM3551) or EN pin (LM3552) is available to

WSON(4mm x 4mm)

put the device into low power shutdown mode. During

shutdown, the feedback resistors and the load are

APPLICATIONS

disconnected from the input to avoid leakage current

•

White LED Camera Flash

paths to ground.

•

White LED Torch (Flashlight)

User programmable soft-start circuitry has been

•

DSC (Digital Still Camera) Flash

integrated to eliminate large inrush currents at start-

up. Over-voltage protection circuitry and a 1.25MHz

•

Cellular Camera Phone Flash

switching frequency allow for the use of small, low-

•

PDA Camera Flash

cost output capacitors with lower voltage ratings. The

•

Camcorder Torch (Flashlight) Lamp

LM3551 and LM3552 are available in a low profile 14-

pin WSON package.

Typical Application Circuits

1

Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of

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

2

All trademarks are the property of their respective owners.

PRODUCTION DATA information is current as of publication date.

Copyright © 2005–2013, 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.