I am working on my master thesis these days, and I am having a serious problem. I am using FDS100 photodiode with LT6268-10 Amp to design a circuit. The required bandwidth for me is 10MHz, and I am using photodiode circuit design wizard to help me with my design. My problem is that when I use the equations to calculate the feedback resistance and capacitance then use these numbers in the design I get a frequency response around 23MHz, which is higher than the bandwidth required. Let's say I have a current around 30uA from the photodiode, and I want the peak voltage value to be 1V, so
1V/30u=33.4KOhm.
Then
Cf=1/(2piRfBW)=0.48pF!!
which is really low, and I am not sure if we can even manage to get it in real life. I am not sure if my methods to calculate these values are correct, but there is a lot of them and they all should give the same results in the end. How do I calculate the equations correctly?