The LTC2208 has an output voltage that can be used for providing the common mode voltage to the differential input signal, named Vcm on pin 3. There are some descrepancies in the datasheet regarding what voltage can be used to bias the common mode voltages of the input pin:
https://www.analog.com/media/en/technical-documentation/data-sheets/2208fc.pdf
This table shows that the Vcm output range is 1.15 to 1.35v
This table shows the Analog Input Common Mode voltage range is 1 to 1.5v
Then this figure shows performance data taken with a common mode range of 0.5 to 2.0v.
I'm most interested in maximizing SFDR and the figure shows that SFDR can be maximized with a common mode voltage near 1.6v, which is higher than the maximum shown in the table above. Is it safe to operate with an external supply that provides 1.6v common mode voltage? If so, can someone provide guidance on the requirements (noise, impedance, etc.) for an external voltage source that would maintain performance equal to that when using pin 3 Vcm.
added question about common mode voltage supply requirements
[edited by: sanjosanjo at 3:43 PM (GMT -4) on 26 Jul 2023]