LM3405_13 Datasheet, PDF (1/29 Pages) Texas Instruments – Constant Current Buck Regulator

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
FEATURES
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•2 V_IN Operating Range of 3V to 15V
• Thin SOT-6 Package
• 1.6MHz Switching Frequency
• 300mΩ NMOS Switch
• 40nA Shutdown Current at V_IN = 5V
• EN/DIM Input for Enabling and PWM Dimming
of LEDs
• Internally Compensated Current-mode Control
• Cycle-by-cycle Current Limit
• Input Voltage UVLO
• Over-current Protection
• Thermal Shutdown
APPLICATIONS
• LED Driver
• Constant Current Source
• Industrial Lighting
• LED Flashlights
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 high power LEDs. With a 0.205V 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 1.6MHz, 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 EN/DIM pin for enabling and
PWM dimming of LEDs, thermal shutdown, cycle-by-
cycle current limit and over-current protection.
TYPICAL APPLICATION CIRCUIT
Efficiency vs LED Current (V_IN = 5V)
V_IN
C1
ON
OFF
D2
V_IN
BOOST
C3
SW
LM3405
D1
EN/DIM
FB
GND
L1
V_OUT
C2 C4
I_F
R1
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PRODUCTION DATA information is current as of publication date.
Products conform to specifications per the terms of the Texas
Instruments standard warranty. Production processing does not
necessarily include testing of all parameters.
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