Re: cmos inverter
If only the invertors input is connected to 5V, then this invertor will function sort of properly with the output pulled to 0V. However the pmos will be in accumulation and you are over stressing the gate oxide of the nmos. The ground bounce should be intereesting too. It should not break the oxide - a 3.3V gate oxide will stand 7V unless its crap. But if you continue to operate the invertor, the oxide will wear out faster and no Fab would sanction this kind of abuse.
The question is, where is the 5V coming from ? The output of another 3.3V invertor? This is a definite no! If you are trying to convert 5V logic to 3V logic then use a conventional down shifter schematic.
Anyway the real question is: do you know how long it takes to get that we invertor from the sparkle is some designers eye, to your bench? The tender loving care during its fabrication, the tears! the joys!......
and then you whack it with a hammer!!!!!
I think mos abuse should be a criminal offence.