This is a related to an old thread, but I wasn't sure if my response would be seen:
I can understand that having IOVDD (3.3V) powered down while SDA/SCL are high could lead to bus problems, but could it actually physically damage the chip? I have a couple of dead ADAU1701's here that may have been subjected to this condition - I really see nothing else it could be as I try to debug the issue. But I don't have strong evidence (yet) that this is what caused the failure. I'm hoping I can either rule it out or blame the cause on this bad IOVDD state. Can you clarify? This wasn't answered definitively in the other thread.
(Failure mode: 1701 is disconnected from the microcontroller, but left connected to the EEPROM. EEPROM seems fine to read manually, but any attempt at "link/compile/download" with the USBi results in SCL stuck low. Haven't been able to talk to the 1701 at all after that, even after resets/power cycles.)