I've recently been doing a bunch of research on analog filtering in preparation for a data acquisition system I'm building. For context, while I'm fairly comfortable with FPGAs and digital/computer engineering, I have far less experience with analog circuitry. I've been reading Analog Filter and Circuit Design Handbook as a reference, as well as a lot of material online.
There's one question I have been unable to find an answer to in all these sources. I would like to use differential signals as far as possible in this circuit, ideally all the way to the ADCs. However, I can't figure out how to construct active, multi-stage filters with fully differential signals. I used Analog Device's filter wizard to spec out a 4th order Chebyshev response comprised of two 2nd order band-pass multiple feedback stages.
I'm now trying to 'translate' it to fully differential form. I had two ideas on how to do this. The first is to use the first stage to convert to single-ended, which isn't ideal and also I don't know if it would work. The second idea uses differential signals the whole way through, which would require swapping out the op-amps recommended by the filter wizard for fully differential ones (no big deal). My question is: will either of these work? It seems highly sketchy to get rid of their grounding scheme like that, but I don't know enough about this to decide if it'll work. Any help or direction to other resources would be appreciated. Here's the sketch of my two ideas.