In order to double output voltage swing I was going to use two OPA548 in difference configuration, connected to opposite inputs like this:
I had one big concern about this circuit - that ground-connected resistor chains on one OP Amp input would affect the gain of the other OP Amp or introduce a bias.
Then I stumbled upon the following circuit in OPA2544 datasheet:
As you can see, it uses second OP Amp with -1 gain connected to the output of the first one.
I think the resistor matching will be much easier to achieve in the second circuit. And there is no cross-affecting resistance on the inputs. However I have a gut feeling that it could be prone to oscillation, and that capacitor looks very much like their way to deal with it.
Question 1: Are there any potential pitfalls in the second circuit?
The isolated amplifier in previous stage is single-supply and has output centered at half positive voltage. For this reason I'd rather connect first OP Amp in difference configuration, to get rid of the DC bias.
Question 2: If I connect first OP Amp in difference configuration, would the mirroring of the output still work as before?
Also, I am going to add adjustable current limit using built-in functionality of OPA548, as discussed here. My understanding is that I only need this on the first OP Amp, the second should fall in line. But since I was wrong about OP Amp behavior many times before I'd like to get a confirmation.
Question 3: Is current limiting on the first OP Amp sufficient?