LM3405

EN/DIM

BOOST

SW

FB

GND

C3

L1

C2

R1

D1

D2

C1

ON

OFF

C4

LM3405

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SNVS429B – OCTOBER 2006 – REVISED MAY 2013

LM3405 1.6MHz, 1A Constant Current Buck Regulator for Powering LEDs

Check for Samples: LM3405

1

FEATURES

DESCRIPTION

Integrated with a 1A power switch, the LM3405 is a

2

•

current-mode

control

switching

buck

regulator

•

Thin SOT-6 Package

designed to provide a simple, high efficiency solution

•

1.6MHz Switching Frequency

for driving high power LEDs. With a 0.205V reference

voltage

feedback

control

to

minimize

power

•

300m

Ω NMOS Switch

dissipation, an external resistor sets the current as

•

needed for driving various types of LEDs. Switching

•

EN/DIM Input for Enabling and PWM Dimming

frequency is internally set to 1.6MHz, allowing small

of LEDs

surface mount inductors and capacitors to be used.

The

LM3405

utilizes

current-mode

control

and

•

Internally Compensated Current-mode Control

internal compensation offering ease of use and

•

Cycle-by-cycle Current Limit

predictable, high performance regulation over a wide

•

Input Voltage UVLO

range of operating conditions. Additional features

include user accessible EN/DIM pin for enabling and

•

Over-current Protection

PWM dimming of LEDs, thermal shutdown, cycle-by-

•

Thermal Shutdown

cycle current limit and over-current protection.

APPLICATIONS

•

LED Driver

•

Constant Current Source

•

Industrial Lighting

•

LED Flashlights

TYPICAL APPLICATION CIRCUIT

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 © 2006–2013, 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.