Hi
I have two connected chips (master/slave), both powered at 3v3.
When power is removed from the slave it's supply rail shows 1.9V - the outputs from the master back feed power into the slave.
The difference is 1.4V. One diode should be the protection diode on the IO and would account for 0.7V but I can't explain where the other diode drop (i assume) would be.
I Googled but still looking for a good explanation.
Thanks