I know hat some chips can be destroyed if a substantial voltage arrives on their I/O pins before the chip is brought up to full power on the Vin pin. So now I am slowly using up an inventory of 5 v. Nanos and ProMinis, and almost every new device I incorporate into a circuit is 3.3 v. Now, depending on how I design the power supply, I worry that a 5 v. chip might reach full power and put a voltage on a 3.3v part that is still coming up to power. Or vice-versa.
Does anyone have any rules of thumb that assure this won't happen, or is it just that during power up, the discrepancy would be too short-lived to cause any problem?
Thanks in advance for any insights.