Calculating output voltage and current of photodiode for input towards ADC
I think current output from photodiode towards ADC does matter. If it is too high or low, ADC will be fried or breakdown due to too much current drain.


If you're doing a purely resistive conversion from PD current to voltage, then the PD current flows through the resistor, not into the ADC. 







simulate this circuit &ndash; Schematic created using CircuitLab

The input to the ADC typically has high impedance (at least kohms), so long as the input voltage doesn't exceed the power supply rails of the ADC device. So not much current will flow into the ADC inputs. If you find you need a load resistor over 1 kohm to obtain the voltage you need, then you might want to re-check this assumption or consider using a trans-resistance amplifier instead of just a resistor for current-to-voltage conversion.