Hi:
(With a particular invite to Bill Sloman, who cued me to OPA655 a while back)
I'll be building a photodiode amp. I was planning to use OPA655 which was "the best" for this purpose a few years ago. It is now obsolete, replaced by OPA656. These are not stocked by my usualy distributors. I will likely give them a call and see if they can get me a handful.
But since a few years have passed, I wonder if any of you analog experts can recommend any new improved models?
My specs/requirements are highly vague. I will be making an amp that can interchance a variety of photodiodes, though not necessarily exchanging widely differing types on the same amp PCB. But the PCB will be used with biased PC and unbiased PV diodes, with capacitances from the low 10pf to 1000pf range. Of course, the compensation will have to be adjusted for these different applications, but I'd like to use an op-amp that can reach 10-20MHz BW with the faster PC diodes.
The amp will also have two stages of amplification, a transimpedance stage (the OPA656 or better op-amp) with selectable gains of 100, 1k,
10k, 100k, and 1M ohm. Then a 1-2-5-10-50-100 amplification stage, followed by a selectable cutoff filter in decades from 10MHz down to 10Hz.A lot of knobs! This will be a general purpose optics lab type photodiode detector. It's main driver is to measure flashlights for luminance. But I'd like to use it for some wide-band experimenting too.
Thanks for input.
Good day!