Tool/software:
Hi, I was using photodiode (65uA reverse light current) with TIA with R1 as 22k and R2 as DNP as shown.
i changed the photodiode to phototransistor(Reverse light current of 0.1-2mA) but now with same circuit (R2 populated as 330ohm) the following happens
1) when R1 = 22K output comes as zero during no transmission, when infact it should have been 2.5V (given at noninverting) and goes to 5V when transmitter on
2) When R1 = 3.3K output is 1.8V when transmitter is off when infact it should have been 2.5V (given at noninverting).
I would like to know why the output is not staying at 2.5V (given at noninverting) when no transmission. Is it an issue with stability? should i change C1?