Hello I am designing a photo-detector to measure the frequency of a 780nm laser and I would like your expert feedback on my circuit so far. The purpose of the device is to provide a feedback path in order to stabilize the frequency. I have modeled a Hamamatsu S5971, with 3pF of capacitance, photo-diode for this simulation. For our test set up we would like to use the least amount of power supplies, therefore I would need op-amps that operate on +/-15 VDC. The current design has the OPA132 operating with the 15 VDC power supply and my gain stage (OPA354) operating with a 2.75 VDC power supply. I forgot to mention, my goal is 1Mohm total, of trans-impedance gain, I am close, a little tweaking of the resistors in the gain stage will accomplish this.
The OPA132 has a GBP of 8MHz and the OPA354 has a GBP of 100MHZ.
Is there an op-amp, other than the OPA 354, that would fit this application with a wider GBP, say 300-400 MHz, that operates with a 15 VDC power supply? I would like to achieve my gain with one op-amp stage in stead of two.
Is the OPA132 my best option at the 15 V operating potential?
I simulated the OPA381 (18MHz GBP) and the OPA380 (90MHz GBP) for the trans-impedance op-amp stage; these configurations delivered a lower overall Band Width compared to the OPA132.
One last question, why is it that when the GBP of the trans-impedance stage increases (plop in the OPA381 or 380), with the same gain stages, my Band Width decreases?