1A Constant Current Buck Regulator - National Semiconductor
Description
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LM3405 500kHz/1.
6MHz 1A Constant Current Buck Regulator for Powering LEDs
ADVANCE INFORMATION
October 2006
LM3405 550kHz/1.
6MHz 1A Constant Current Buck Regulator for Powering LEDs
General Description
Integrated with a 1A power switch, the LM3405 is a current mode control switching buck regulator designed to provide a simple, high efficiency solution for driving LEDs.
With a 0.
2V reference voltage feedback control to minimize power dissipation, an external resistor sets the current as needed for driving various types of LEDs.
Switching frequency is internally set to 550kHz (LM3405-Y) or 1.
6MHz (LM3405-X), allowing small surface mount inductors and capacitors to be used.
The LM3405 utilizes current mode control and internal compensation offering ease of use and predictable, high performance regulation over a wide range of operating conditions.
Additional features include user accessible enable/ dim pin for enabling and PWM dimming of LEDs, thermal shutdown, current limit and over voltage protection.
Features
n Thin SOT23-6 package n 4.
0V to 20V input voltage range n 550kHz (LM3405Y) and 1.
6MHz (LM3405X) switching frequencies n 300mΩ NMOS switch n 30nA shutdown current n Enable/DIM input for enabling and PWM dimming of LEDs n Requires only low value, ceramic capacitors n Input voltage UVLO n Internally compensated current mode control n Thermal shutdown
Applications
n LED Driver n Constant Current Source
Typical Application Circuit
20178901
Connection Diagrams
20178905
20178960
6-Lead TSOT NS Package Number MK06A
Pin 1 Indentification
© 2006 National Semiconductor Corporation
DS201789
www.
national.
com
LM3405 500kHz/1.
6MHz 1A Constant Current Buck Regulator for Powering LEDs
Physical Dimensions
inches (millimeters) unless otherwise noted
6-Lead TSOT Package NS Package Number MK06A
National does not assume any responsibility for use of any circuitry described, no circuit patent licenses are implied and National reserves the right ...
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