I have dissasembled a pick up head from a CD Rom. I can control the laser and but I also want to "read" the photodiode that senses the light reflected back. It is packaged in a clear plastic and has 8 pins. I can't see the entire ic but I can access 4 of its pins. Now I'm trying to determine what those pins do but I need more data about how they operate. I found a very similar device OPT101 that explains many of the external components of my photodiode. Beside the ic there are 2 capacitors,1 fixed resistor and one variable resistor.
Although the datasheet is different from my ic there are many similar traits.
Counting pins from left to right, here are my assumptions:
I think pin 1 is the actual output. From the datasheet , the feedback resistor(1M) is connected to output.
Pin 3 is ground.
either 2 or 4 is vcc(one of them I think is -V which I don't need)
I say pin 3 is ground because 2 and 4 are connected through a capacitor to this line.
To test which line is vcc I think there is a way: simply,if I connect the right line to 5v(or the lowest amount of voltage possible so that in case of wrong assumptions the damage will be minimum) the chip will work and I will be able to read the voltage from Output. If it's the wrong pin deduce the other one is vcc and hope the chip is still good.
What I want is more datasheets from similar products. If ,from your experience , you have seen anything like this one please write about it. And am I missing something(like the capacitors actually could be wired to vcc) that may help me find the pins ?