Data Sheet

3V3 power output: This pin gives access to the output of the internal 3.3 V regulator inside the ATmega32U4.
The microcontroller uses this regulated voltage for USB signaling, but up to about 50 mA is available for powering
external circuits or devices.
When the A-Star 32U4 Micro is being powered through VIN, the sum of the 5V output current, 3V3 output current,
GPIO output current, and current used by the board itself should not exceed the 100 mA that the regulator can provide.
Pololu A-Star 32U4 User’s Guide © 2001–2014 Pololu Corporation
3. A-Star 32U4 Micro Page 8 of 47