I'm trying to design a differential ADC circuit using the TI ADC10065 chip. It's a 10-bit, 65 MSPS ADC. In the datasheet they provide a sample circuit with a transformer in it. There's also a circuit generated by TI's ADC topology tool. It uses a differential op-amp.
Now I have a few questions:
I think I can tell what resistor/capacitor values to use for
C1=C2=25 pF. Is this correct?
Is there a reason I should be using one circuit over the other? Why? I remember reading a document somewhere recommending the differential op-amp method for higher frequency ADC's (it came from another semiconductor manufacturer, don't remember which one).
How do I choose the value of
RT (termination resistor)? Is it even necessary?
R3/R4 are there any design considerations I need to take into account such as matching impedance, or am I free to choose any
R2=R4 which meets the desired gain I want?
Should I buffer the input to the transformer/differential op-amp with voltage follower op-amps?