In electrical characteristics section of the datasheet of the LTC2947, it is mensioned that the OVDD should be applied earlier or at the same time as AVCC/DVCC. In our application however the OVDD is generated from the Input supply we want to monitor. This input supply is also connected to AVCC/DVCC like the example in "Typical Application" of the datasheet.
Furthermore in the "Digital Interface" section following is mentioned:
Selecting SPI or I2C Serial Interface
The serial interface of the LTC2947 can operate in either
SPI or I2C mode. To select SPI mode, tie AD0 to OVDD.
To select I2C mode, connect AD0 according to Table 3.
The LTC2947 selects SPI or I2C mode by reading pin AD0
when DVCC is powered up. To ensure proper mode detection,
OVDD should be powered up before DVCC.
In our case we would like to use I2C mode and will connect AD0 to GND. Does the LTC2927 work properly in I2C mode if we apply OVDD after AVCC/DVCC