SparkFun Buck Regulator Breakout - 3.3V (AP3429A)

SparkfunSKU: COM-21337
Sale price £4.75
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The SparkFun 3.3V Buck Regulator Breakout features the AP3429A from Diodes Inc., a 2A step-down DC-DC converter with an input voltage range of 2.7V to 5.5V. This full-size, 1in. x 1in. version of our buck regulator boards is configured to provide a regulated 3.3V output (from a 3.9 to 5.5V input voltage range), which is controlled by an EN (enable) pin. To dissipate excess heat, a 0.6in. x 0.5in. A copper pad is provided to attach a heat sink to the bottom of the board.

As a full-size buck regulator breakout, additional options for connecting input and output power are available. There is a pre-assembled screw terminal for a non-permanent connection, the option to solder on a barrel jack for an external power supply, and five PTH pins to create a more permanent installation. Our full-size buck regulators also come with a red, power indication LED that light up when the power output is enabled. This board has four mounting holes compatible with 4-40 hardware.

Get Started With The Sparkfun AP3429A Buck Regulator Guide


Buck Board:

  • 1in. x 1in. PCB layout
  • Three power input/output options:
    • Pre-assembled 4-pin screw terminal
    • Five 0.1in. spaced PTH pins
    • Four plated slots for a DC barrel jack (input only)
  • Power connections:
    • VIN - Power In (3.9V to 5.5V)
    • GND - Common Ground
    • VOUT - Power Out (Regulated 3.3V)
    • EN - Enable (Pull high to enable the power output)
  • Red, power LED indicator
  • 0.5in. x 0.6in. Plated copper pad (for heat sinks)


  • VIN: 2.7V to 5.5V
  • VOUT: 0.6V to VIN
  • 2A Continuous Output Current
  • 90µA No-Load Quiescent Current
  • 1MHz Switching Frequency
  • Protection Circuitry
    • Undervoltage Lockout (UVLO)
    • Input Overvoltage Protection
    • Over Current Protection
      • Cycle-by-Cycle Peak Current Limit
    • Thermal Shutdown (160°C/320°F)


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