The Arduino Nano is a small, complete, and breadboard-friendly board based on the ATmega328. It has more or less the same functionality of the Arduino Duemilanove, but in a different package. It lacks only a DC power jack, and works with a Mini-B USB cable instead of a standard one. 

Specifications

• Microcontroller:     Atmel ATmega328 / ATmega328B
• Operating Voltage (logic level):     5 V
• Input Voltage (recommended):     7-12 V
• Input Voltage (limits):     6-20 V
• Digital I/O Pins:     14 (of which 6 provide PWM output)
• Analog Input Pins:     8
• DC Current per I/O Pin:     40 mA
• Flash Memory:     32 KB of which 2 KB used by bootloader
• SRAM:     2 KB
• EEPROM :    1 KB
• Clock Speed:     16 MHz
• Dimensions:     0.73" x 1.70"
• Length:     45 mm
• Width:     18 mm
• Weigth:     5 g

Packing List

• 1x Arduino Nano v3.0
• Pin headers soldered

Clearance Unit Notes !!!

• Board cannot be uploaded thru USB but can be uploaded thru ICSP pin.
• Board using custom bootloader & custom board installation needed on the IDE.
• Refer the Attachment tab > ATmega328PB for more info.

Driver

• ATmega16U2 (Atmel) - https://www.arduino.cc/en/software (Driver comes with IDE)

• CH340 Series (WCH) - https://www.wch-ic.com/downloads/CH341SER_ZIP.html

• CP2102 (Silicon Labs) - https://www.silabs.com/developers/usb-to-uart-bridge-vcp-drivers

• FT232RL (FTDI Chip) - https://ftdichip.com/drivers/vcp-drivers/

• CH9102 (WCH) - https://www.wch-ic.com/downloads/CH343SER_ZIP.html