CPU Features Operating voltage fSYS= 32.768kHz: 2.2V~5.5V fSYS= 910kHz: 2.2V~5.5V fSYS= 2MHz: 2.2V~5.5V fSYS= 4MHz: 2.2V~5.5V fSYS= 8MHz: 3.3V~5.5V TinyPowerTM technology