I'm working with a mid-infrared (~4um) photodiode model Lms43PD-03-CG (Datasheet) and a matching LED (Datasheet). (I can't switch from this photodiode/LED pair) I'm trying to make a functioning photodiode amplifier but have not been able to get the photodiode to respond.
I've tried a basic photodiode amplifier but no feedback resistor value would work. I tried adding a capacitor to stabilize the trans-impedance amplifier but no values appeared to work. I tried biasing the positive input of the op amp to not ride the rails, and still nothing.
I've recently started experimenting with using photoconductive mode (to increase the power source of the photodiode), but don't know/can't find much information about designing a photoconductive photodiode amplifier. I even tried using Analog's design tool but photodiode's specifications our outside of their photodiode parameters.
This is the design that I'm looking to design around with the photodiode being reverse biased. I am connecting the photodiode amplifier to a lock-in amplifier once I get the photodiode responding to light and creating a voltage response. I am checking the output signals with an oscilloscope.
Some other important information:
The op-amp I am using is the MCP6002. The desired frequency is at most 10kHz.
Here are my questions:
In the photodiode datasheet, there is a reverse voltage of 0.1V. Is this the same as the breakdown voltage, the max voltage that photodiodes may safely receive?
Would this circuit require a capacitor? If so, what equations should I use to determine this capacitor value? I've tried several such as TI's photodiode design guide to no avail.
What should I be cautious about designing this photodiode amplifier? I'll make sure to bias the positive input to avoid the rails.
What else could be causing this circuit to not respond? No matter how much I shine a MIR LED to the photodiode from a short distance, it doesn't respond.