The AT90USB647-AU from Microchip Technology is an AVR 90USB 8-bit microcontroller Integrated Circuit running at 16 MHz with 64 KB (64K x 8) flash, in a 64-TQFP (14x14) package.
The AT90USB647-AUR from Microchip Technology is an 8-bit AVR microcontroller Integrated Circuit operating at 16 MHz, with 64 KB (64K x 8) flash memory, in a 64-TQFP (14x14) package.