Hi all. I need any opinion about connecting USB over 68ohm resistor . if MCU is powered from less then +5V we can damage pin on MCU??? on data sheet is write so any voltage to pin can be VCC+0.5V but if we power MCU from 3.3V (use 68ohm resistor) this value is 3.8V ,risk to damage this pin??? if use resistor then different in +5V and 3.3 is 1.7V and on this if use 68ohm resistor then current is
0.025A and it's more then one pin can give, but if use maximal voltage input then real voltage is 1.2V and current is 0.017A
or what????
many schematic use zener diode , some don't , I too don't use zener only resistor .
what is your opinion????
regards
