LM3407 Datasheet, PDF (1/16 Pages) National Semiconductor (TI) – 350 mA, Constant Current Output Floating Buck Switching Converter for High Power LEDs

January 18, 2008
LM3407
350 mA, Constant Current Output Floating Buck Switching
Converter for High Power LEDs
General Description
The LM3407 is a constant current output floating buck switch-
ing converter designed to provide constant current to high
power LEDs. The device is ideal for automotive, industrial and
general lighting applications. The LM3407 has an integrated
power N-MOSFET that makes the application solution com-
pact and simple to implement. An external 1% thick-film re-
sistor allows the converter output voltage to adjust as needed
to deliver constant current within 10% accuracy to a serially
connected LED string of varying number and type. Converter
switching frequency is adjustable from 300 kHz to 1 MHz. The
LM3407 features a dimming input to enable LED brightness
control by Pulse Width Modulation (PWM). Additionally, a
separate enable pin allows for low power shutdown. An ex-
posed pad eMSOP-8 package provides excellent heat dissi-
pation and thermal performance. Input UVLO and output
open-circuit protection ensure a robust LED driver solution.
Features
■ ^{Input operating range 4.5V to 30V}
■ ^{Output voltage range: 0.1V}_IN ^{to 0.9V}_IN
■ ^{Accurate constant current output}
■ ^{Cycle-by-Cycle current limit}
■ ^{Independent device enable (CMOS compatible) and PWM}
dimming control
■ ^{Converter switching frequency adjustable from 300 kHz to}
1 MHz
■ ^{No external control loop compensation required}
■ ^{Supports ceramic and low ESR output capacitors}
■ ^{Input Under Voltage Lock Out (UVLO)}
■ ^{Thermal shutdown protection}
■ ^{eMSOP-8 Package}
Applications
■ ^{LED Driver}
■ ^{Constant Current Source}
■ ^{Automotive Lighting}
■ ^{General Illumination}
■ ^{Industrial Lighting}
Typical Application
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