Hello:
Bob, thanks.
we use range1 , because our power supply is only about 3.6V and Vref + is 2.5V, Vref- is ground. The data sheet page 18 says we have to use range1.
Adding offset voltage is intended to bring the digital output span centered, when analog log input change from extreme low to extreme high.
Our design is on board,It is not simple to generate the right analog input to check.
It seems I need to generate the analog differential input voltage and test digital output .
Thanks