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


1.6MHz 1A Constant Current Buck Regulator for Powering LEDs

Recommended alternative parts

  • LM3405A  -  Extended Input Voltage Range Up To 22V


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.


  • VIN Operating Range of 3V to 15V
  • Thin SOT-6 Package
  • 1.6MHz Switching Frequency
  • 300mΩ NMOS Switch
  • 40nA Shutdown Current at VIN = 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

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Parametrics Compare all products in LED Lighting - Illumination

Input Voltage (Type)
Vin (Min) (V)
Vin (Max) (V)
Iout (Max) (A)
Vout (Min) (V)
Vout (Max) (V)
Regulated Outputs (#)
Dimming Method
Switching Frequency (Min) (kHz)
Switching Frequency (Max) (kHz)
Iq (Typ) (mA)
Vref (V)
UVLO Thresholds On/Off (V)
Special Features
Operating Temperature Range (C)
Approx. Price (US$)
LM3405 LM3405A
DC/DC     DC/DC    
3     3    
15     22    
1     1    
0.2     0.2    
13.5     20    
1     1    
Buck     Buck    
PWM     PWM    
Inductive     Inductive    
1600     1600    
1600     1600    
1.8     1.8    
0.205     0.205    
2.74 / 2.3     2.74 / 2.3    
Thermal Shutdown
Integrated Switch    
Thermal Shutdown
Integrated Switch    
Catalog     Catalog    
-40 to 125     -40 to 125    
6SOT     6SOT
0.45 | 1ku     0.50 | 1ku