ATMEGA32U4-MU

• 8-Bit AVR Core Running at Up to 16M Hz
• 32 KB Flash Program Memory with 2.5 KB RAM
• Integrated USB Channel Plus UART I2C SPI and I2S Interfaces
• 26 Programmable I/O Lines with 12 ADC Channels and 8 PWM Channels
• 2.7V to 5.5V Supply Range and -40°C to 85°C Operation
• 44-Terminal QFN Surface-Mount Package Measuring 7.1mm by 7.1mm

The Microchip ATMEGA32U4-MU is an 8-bit AVR microcontroller in a 44-terminal QFN package measuring 7.1 mm by 7.1 mm with a 950 µm profile height. It runs at up to 16 MHz from a 2.7 V to 5.5 V supply and integrates 32 KB of flash program memory with 2.5 KB of RAM. The peripheral set includes an on-chip USB channel, one UART, one I2C and two SPI channels plus I2S, 26 programmable I/O lines, 12 ADC channels, 8 PWM channels and 5 timer/counters, together with brown-out detect and reset, power-on reset and a watchdog timer. ATMEGA32U4-MU is a surface-mount, lead-free, RoHS-compliant part specified from -40 °C to 85 °C and driven from an external oscillator per its recorded attributes.

The defining feature of this device against the rest of the 8-bit AVR family is the on-chip USB channel, which lets the microcontroller enumerate directly as a USB device without an external bridge chip. That is why the ATMEGA32U4-MU is a standard choice for keyboards, game controllers, card readers, data-acquisition dongles, USB-connected test instruments and the many development boards built around it. The 32 KB of flash and 2.5 KB of RAM place it in the mid-range for control-oriented firmware: state machines, sensor polling and protocol handling rather than signal processing or a full network stack. Its 12 ADC channels and 8 PWM outputs also make it a common single-chip controller for small motor, lighting and sensor hub designs, while the wide 2.7 V to 5.5 V supply range lets one part serve both 3.3 V and 5 V systems.