Hi guys, once more, thank-you for your help!
It's been some time since you have replied, but it's not that I'm not interested in this, it is only that unfortunately my weekdays have been crazy ehehe...
Anyway,
I think I understood when LvW said that the infinite input impedance is allowing the infinite current gain... it makes perfect sense (for the moment, at least hehe). Anyway, since I will be working with CMOS amplifiers with gate input, I think it is safe to assume an "infinite input impedance".
Then, Keith, I am getting some very similar results here when I simulate with a real op-amp (with a voltage DC gain of 200). What voltage DC gain does the op-amp that you used for this simulation has?
What I would like to know is how the DC voltage gain influences the feedback transimpedance gain... I mean, if you increased your DC gain you could then make the 1Meg resistor work, but maybe not one of 100Meg?
Maybe you already have tried to explain that with the sentence "There you have an input bias current and reach a limit where the output is based on the current gain of the amplifier.", but I really did not understood this sentence very well... if you could elaborate a little bit more on this I would be very grateful!
Thanks again!