Hi,
The datasheet for OPA820 gives noise curves only to 10 MHz although the part has gain out to several hundred MHz. Does the noise remain flat above 10 MHz? Using the PSpice model I seem to see the noise rising starting at about 10 MHz but I don't know if that is for real. I will check on the lab bench soon but it would be helpful to have a general answer in advance.
The application is simply an inverting gain ~ -1 using Rf=499 Ohm.