We have a legacy 5V system that makes heavy use of analog sensors and various other 5V digital IOs. We're looking at moving to an ARM MCU to bring this design in line with our newer systems which are all Cortex-M3 based. I would prefer to stay with a 5V MCU so I don't lose accuracy on the ADC inputs and so I won't have to run an extra 3.3V power supply. I've been searching for 5V compatible ARM MCUs and only found the FM3 series from Fujitsu, which it seems like almost no one stocks. My questions are:
Is it worth it to continue attempting to use a 5V micro or should we move to voltage-dividers for the ADC and level shifters/transistors for the digital IO?
Does anyone have experience with the Fujitsu FM3 line?
Are there any other 5V compatible ARM microcontrollers out there?