Adafruit Pro Trinkets

Adafruit Pro Trinkets are available in 3V 12MHz and 5V 16MHz versions with the ATmega328 at their core, the same chip in the Arduino UNO/Mini/etc. at the same speed and voltage. The 3V version uses 3V logic and a 12MHz clock which is good for lower-power and lower-voltage setups. 

The Pro Trinkets are like an Arduino Pro Mini but with more pins, FLASH, and RAM. The Pro Trinket has 18 GPIO, 2 extra analog inputs, 28K of flash, and 2K of RAM. The Trinkets have onboard USB bootloading support and feature a MicroUSB jack. Optiboot support has been added to program the Pro Trinket over USB or with an FTDI cable.

The Pro Trinket PCB measures 1.5x0.7x0.2" (without headers) with the same capability as an Arduino UNO. The Pro Trinket is programmable using the Arduino IDE and works with 99 percent of Arduino projects out of the box.


  • ATmega328 onboard chip in QFN package
  • 12MHz or 16MHz clock rate, 28K FLASH available
  • USB bootloader with a nice LED indicator
  • Headers for an FTDI port for reprogramming
  • Micro-USB jack for power and/or USB uploading
  • On-board 3.3V or 5V power regulator with 150mA output capability and ultra-low dropout
  • Up to 16V input, reverse-polarity protection, thermal and current-limit protection
  • Power with either USB or external output (battery)
  • On-board green power LED and red pin #13 LED
  • Reset button for entering the bootloader or restarting the program
  • Works with 99% of existing Arduino sketches anything that doesn't use more than 28K, and doesn't require pins 2 or 7


Published: 2016-07-12 | Updated: 2022-03-11