The datasheet states these are 3.3V CMOS inputs but the ac specification on Page 3 has a minimum input voltage, high (VIH) of 1.0V for digital inputs.
I agree with you, the data sheet implies the I2C lines should work with 1.8V signals. They are 5V tolerant. All this said I have no hard data where we tested the device with a 1.8V I2C interface.
To be absolutely safe you might design a new board with a bus level translator like the PCA9306 and a bypass path so you could eliminate this part for cost savings when you proven 1.8V I2C works correctly.
Thank you for the response that seems like the safest way to proceed.
Where you able to test the I2C interface at 1.8V?
We have not tested at 1.8V we are just starting the design phase, we will not have physical boards back until September to be able to do any testing.
Retrieving data ...