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1.6MHz, 1A Constant Current Buck Regulator for Powering LEDs

Inventory: In stock


Limit:  2

Features for the LM3405XEVAL

  • VIN operating range of 3V to 15V
  • Thin SOT23-6 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


  • LED Driver
  • Constant Current Source
  • Industrial Lighting
  • LED Flashlights


Description for the LM3405XEVAL

The LM3405 demo board is configured to drive a series string of high power, high brightness LEDs at a forward current of 1A using the LM3405 constant current buck regulator. The board can accept a full input operating range of 3V to 15V. The converter output voltage adjusts as needed to maintain a constant current through the LED array. The LM3405 is a step-down regulator with an output voltage range extending from a VO(MIN) of 205mV (the reference voltage) to a VO(MAX) determined by the maximum duty cycle (typically 94%). It can drive up to 3 LEDs in series at 1A forward current, with the single LED forward voltage of approximately 3.7V (Typical of white, blue, and green LEDs using InGaN technology).