I don't see why you're so against the op-amp set up for photodiodes. People use them for really high-speed circuits all the time. Photomultipliers are crazy when it comes to low signal to high signal leaps(literally on the single photon/electron level), granted they traditionally also run off of high voltage sources... Yes op-amps and TIA circuits do have to be tuned very well to perform as desired. I am not an expert. I also understand fine tuning op-amps can be deep water for non-experts. At the same time, I want to learn about them because I frankly think they are genious. Yes the current for a PIN photodiode is the linear characteristic verses irradiance as seen in almost all of the data sheets. I also figured that was the point of using a transimpedance op-amp? Maybe I am wrong, or missing the point again. I can put it on PCB, and shield it but I do not believe that I am getting the behaviour I want from the circuit yet, so I don't want to 'finalize' anything until I do. Meaning I have no problem with instability for now so long as I am getting a 'good enough' gain in the region I want.
Checking the datasheet for the op-amp that I have selected, it has a slew rate of 4V/uS(50pF capacitor and 10kOhm load resistor present). That's plenty fast not taking into account the capacitance of the photodiode. 1-3ms if I hit the 'rails' which I don't really plan too and would prefer not too. The capacitance of the photodiode I will be using eventually is 400pF at 5V reverse. Also it has a sensitivity of 9nA/lux. Which should be way lower then I need. I should also mention that my changes in light intensity or irradiance are pretty gradual. Meaning it's not an "on/off" type jump, more like 0.110V(t=1ms) to 0.113V(t=2ms), then to 0.117V(t=3ms), etc. ?s there something that I am missing here, or is the LTC1050 not suitable for this application? Like I said I had pretty reasonable results with an LM358N(which to my understanding is essentially junk for these types of applications), but the over-all noise in my circuit was awful. Not noise limitted too the op-amp itself, to everything else going on(back EMF from a 12V 1A motor, PWM signals on a common ground, etc).
Anyways. I still haven't been really clearly suggested any way to amplify the 0-0.250V signal I am getting to say 0-2.5V. Is there a key-word I am missing? Should I do a dual stage amplification? Is there a way I can clip the signal above roughly 0.250V and scale that input into an op-amp(would even that help)?