| PartNumber | ATMEGA16U2-MUR | ATMEGA16U4-AU | ATMEGA16U4-AUR |
| Description | 8-bit Microcontrollers - MCU USB 8K FLASH 16 MHz | 8-bit Microcontrollers - MCU 16K Flsh, 1K EEPROM 2.5K SRAM | 8-bit Microcontrollers - MCU USB 16K FLASH 16 MHz |
| Manufacturer | Microchip | Microchip | Microchip |
| Product Category | 8-bit Microcontrollers - MCU | 8-bit Microcontrollers - MCU | 8-bit Microcontrollers - MCU |
| RoHS | Y | Y | Y |
| Mounting Style | SMD/SMT | SMD/SMT | SMD/SMT |
| Package / Case | QFN-32 | TQFP-44 | TQFP-44 |
| Series | ATmega16U2 | ATmega16U4 | ATmega16U4 |
| Core | AVR | AVR | AVR |
| Data Bus Width | 8 bit | 8 bit | 8 bit |
| Maximum Clock Frequency | 16 MHz | 16 MHz | 16 MHz |
| Operating Supply Voltage | 2.7 V to 5.5 V | 2.7 V to 5.5 V | 2.7 V to 5.5 V |
| Packaging | Reel | Tray | Reel |
| Product | MCU | MCU | MCU |
| Brand | Microchip Technology / Atmel | Microchip Technology / Atmel | Microchip Technology / Atmel |
| Processor Series | megaAVR | megaAVR | megaAVR |
| Product Type | 8-bit Microcontrollers - MCU | 8-bit Microcontrollers - MCU | 8-bit Microcontrollers - MCU |
| Factory Pack Quantity | 5000 | 160 | 1500 |
| Subcategory | Microcontrollers - MCU | Microcontrollers - MCU | Microcontrollers - MCU |
| Tradename | AVR | AVR | AVR |
| Unit Weight | 0.006653 oz | 0.077179 oz | - |
| Program Memory Size | - | 16 kB | - |
| Data RAM Size | - | 1.25 kB | - |
| ADC Resolution | - | 10 bit | - |
| Number of I/Os | - | 26 I/O | - |
| Minimum Operating Temperature | - | - 40 C | - |
| Maximum Operating Temperature | - | + 85 C | - |
| Height | - | 1.05 mm | - |
| Length | - | 10 mm | - |
| Program Memory Type | - | Flash | - |
| Width | - | 10 mm | - |
| Data RAM Type | - | SRAM | - |
| Data ROM Size | - | 512 B | - |
| Data ROM Type | - | EEPROM | - |
| Interface Type | - | SPI, TWI, USART | - |
| Moisture Sensitive | - | Yes | Yes |
| Number of ADC Channels | - | 12 | - |
| Number of Timers/Counters | - | 5 Timer | - |
| Supply Voltage Max | - | 5.5 V | - |
| Supply Voltage Min | - | 2.7 V | - |