This Pro Micro 5V 16M Mini Leonardo Micro-controller Development Board For Arduino development board has 4 channel 10 bit ADC, 5 PWM pins, 12 DIO, and a hardware serial connection Rx and Tx you are familiar with Running on 16MHz and 5V, this board will remind you a lot of other Arduino compatible boards that you like.
There is a voltage regulator on board, so it can accept up to 12V DC.
The Micro is a microcontroller board based on the ATmega32U4. It has 20 digital input/output pins (of which 7 can be used as PWM outputs and 12 as analog inputs), a 16 MHz crystal oscillator, a micro USB connection, an ICSP header, and a reset button.
It contains everything needed to support the microcontroller; simply connect it to a computer with a micro USB cable to get started. It has a form factor that enables it to be easily placed on a breadboard.
The Micro board is similar to the Arduino Leonardo in that the ATmega32U4 has built-in USB communication, eliminating the need for a secondary processor. This allows the Micro to appear to a connected computer as a mouse and keyboard, in addition to a virtual (CDC) serial / COM port.
If you supply an unstable power supply board, be sure to connect to the “RAW”, not on the VCC pin. It has also added a PTC fuse and diode protection to the power circuit and to correct the RX and LED TX circuits.