LM3405A

EN/DIM

BOOST

SW

FB

GND

C3

L1

C2

R1

D1

C1

ON

OFF

C4

D2

D3

LM3405A

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SNVS508C – OCTOBER 2007 – REVISED MAY 2013

LM3405A 1.6MHz, 1A Constant Current Buck LED Driver with Internal Compensation in

Tiny SOT and VSSOP PowerPAD Packages

Check for Samples: LM3405A

1

FEATURES

DESCRIPTION

The LM3405A is a 1A constant current buck LED

2

•

driver designed to provide a simple, high efficiency

•

Drives up to 5 High-Brightness LEDs in Series

solution for driving high power LEDs. With a 0.205V

at 1A

reference voltage feedback control to minimize power

•

Thin SOT-6 package and VSSOP-8 PowerPAD

dissipation, an external resistor sets the current as

needed for driving various types of LEDs. Switching

Packages

frequency is internally set to 1.6MHz, allowing small

•

1.6MHz Switching Frequency

surface mount inductors and capacitors to be used.

•

EN/DIM Input for Enabling and PWM Dimming

The LM3405A utilizes current-mode control and

of LEDs

internal compensation offering ease of use and

predictable, high performance regulation over a wide

•

300m

Ω NMOS Switch

range of operating conditions. With a maximum input

•

voltage of 22V, it can drive up to 5 High-Brightness

•

Internally Compensated Current-mode Control

LEDs in series at 1A forward current, with the single

•

Cycle-by-cycle Current Limit

LED

forward

voltage

of

approximately

3.7V.

Additional features include user accessible EN/DIM

•

Input Voltage UVLO

pin for enabling and PWM dimming of LEDs, thermal

•

Over-current Protection

shutdown, cycle-by-cycle current limit and over-

•

Thermal Shutdown

current protection.

APPLICATIONS

•

LED Driver

•

Constant Current Source

•

Industrial Lighting

•

LED Flashlights

•

LED Lightbulbs

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 © 2007–2013, 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.