I am using the ADA4932 as a SE to DE ADC driver. The design notes and reference designs show several examples, but they all have input signals centered on 0V. Are there some design guidelines for dealing with input signals that have a common mode voltage? I have an input signal riding at 2.5V. Output CM is 2V. Thanks.
OK. That does make some intuitive sense. I'm using the last example from the data sheet here. The 50 Ohm source is terminated with an impedance of 50 Ohms. If I assume that the input Vcm is also divided by two as is the signal, I would set the Vn input termination voltage level to 1.25V. It gets me close, but there is still a small 24mV offset in output Vcm. It is not intuitively obvious (well, to me anyways) how to trim that offset to zero.
George,
Think of it this way. You want to take the difference between 2.5V and your signal.
Harry
