2 layers89.5 × 63.5 mm

Boards in 1 GitHub repository, designed in KiCad, that use the AT90USB646-MU by Microchip Technology (-40℃~+85℃ 10bit 16MHz 2.7V~5.5V 2KB 48 4KB 64KB 8 Bit AVR Built-in FLASH QFN-64-EP(9x9) Microcontrollers (MCU/MPU/SOC) ROHS). See how each wires it, with its parts, size, README and files; the AT90USB646-MU’s symbol, footprint and pinout are on its own page.
