Adafruit
AP3429A 3.3V Buck Converter Breakout - 3.3V Output 1.2A Max
The AP3429A Buck Converter Breakout steps down 3.4–5.5V input to a stable 3.3V output at up to 1.2A, with 90–95% efficiency. It's ideal for powering 3.3V cir...
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The AP3429A Buck Converter Breakout steps down 3.4–5.5V input to a stable 3.3V output at up to 1.2A, with 90–95% efficiency. It's ideal for powering 3.3V circuits from LiPo batteries, 3× alkaline cells, or USB power sources.
Designed to be pin-compatible with the LM1117-3.3V TO-220 regulator, you can swap it in for significantly better efficiency. An enable pin lets you shut down the output completely by pulling it low. Comes fully assembled and tested with header included for breadboard use.
Key Features
- 3.3V Regulated Output – Up to 1.2A load current
- Wide Input Range – 3.4V to 5.5V (LiPo, 3× alkaline, USB)
- High Efficiency – 90–95% typical efficiency
- 1MHz Fixed Frequency – Compact inductor and low noise
- Enable Pin – Tie low to shut down output completely
- LM1117-3.3V Pin Compatible – Drop-in replacement for TO-220 regulators
- Breadboard Ready – Header included for easy prototyping
Specifications
- IC: AP3429A
- Input Voltage: 3.4–5.5V
- Output Voltage: 3.3V
- Max Output Current: 1.2A
- Switching Frequency: 1MHz
- Efficiency: 90–95%
Ideal For
- Portable projects powered by LiPo or alkaline batteries
- USB-powered 3.3V circuits
- Replacing inefficient linear regulators like the LM1117
Package Contents
- 1× AP3429A 3.3V buck converter breakout (assembled and tested)
- 1× Header strip
Need a wider input range? Check out the MPM3610 3.3V Buck Converter Breakout with up to 21V input.
Jargon buster
Plain-language definitions for the technical terms used above.
- breakout
- A breakout board carries a small or fine-pitched component and brings its connections out to standard, breadboard- and header-friendly pins. Describing a part as a breakout means it can be wired into a project without soldering directly to the component's tiny contacts.
- Buck converter
- A power circuit that reduces a higher DC voltage to a lower DC voltage. It is useful when your supply voltage is too high for a module or microcontroller and you want less heat and better efficiency than a simple linear regulator.
- LiPo
- A LiPo (lithium polymer) battery is a rechargeable lithium battery widely used in portable projects because it is light and compact. LiPo cells need correct charging circuitry and careful handling to stay safe, so equipment that supports LiPo generally includes charging or protection hardware suited to that battery type.
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