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 Features 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) AP3429A: * 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) Resources * Schematic * Eagle Files * Board Dimensions * Hookup Guide * Datasheet (AP3429A) * AP3428 Application Note * Manufacturer's Product Page (AP3429A) * Technical Documentation * Diodes Technical Support Page * GitHub Hardware Repo https://elecena.pl/product/23580038/sparkfun-buck-regulator-breakout-3-3v-ap3429a 2023-06-02 https://elecena.pl/product/23580038/sparkfun-buck-regulator-breakout-3-3v-ap3429a 2023-12-27 https://elecena.pl/product/23580038/sparkfun-buck-regulator-breakout-3-3v-ap3429a 2024-09-18 https://elecena.pl/product/23580038/sparkfun-buck-regulator-breakout-3-3v-ap3429a 2024-11-29 https://elecena.pl/product/23580038/sparkfun-buck-regulator-breakout-3-3v-ap3429a 2024-11-30 https://elecena.pl/product/23580038/sparkfun-buck-regulator-breakout-3-3v-ap3429a 2025-04-10 https://elecena.pl/product/23580038/sparkfun-buck-regulator-breakout-3-3v-ap3429a 2025-08-05 https://elecena.pl/product/23580038/sparkfun-buck-regulator-breakout-3-3v-ap3429a 2025-11-28 https://elecena.pl/product/23580038/sparkfun-buck-regulator-breakout-3-3v-ap3429a 2025-11-29