Dear Team,

I am designing a trans impedance amplifier using OPA365AQDBVRQ1 . My photo-diode is VEMD2023SLX01 .The circuit diagram is given below.

Do I need to place a resistor between 3.V and Cathode of the diode.

I believe it is not required because R1 is present .Please correct me if I am wrong.

May I know your thoughts

 

You may need to bypass the voltage source to the diode with a resistor in series and a capacitor to ground in the case of unacceptable noise being on your power supply. Experimentation will help determine the values.

 

Okay You mean an RC LPF at the output of 3V3 rail

 

Okay You mean an RC LPF at the output of 3V3 rail

That does sound reasonable if needed. Then possibly a small cap across R3 also.
Another possibility is a very small cap across R1 instead of those two. It partly depends on the speed of the op amp too.

 

the U1 output cannot go higher than supply voltage which is 3.3V so diode is never forward biased. in other words resistor in series with the diode is not needed.

 

I hasten to disappoint you all. This electronic circuit will not work. A negative voltage source is required and a resistor must be connected to the anode and this source. In this case, the output voltage will be normal.

 

Why you need a negative voltage source

 

That's my advice. Note: the resistor always has a parasitic capacitance!

 

I will keep a resistor in parallel with feedback resistor.It was there in my simulation.Forgot to keep in my schematic.

This is a single supply opeartion.

 

Do you want to reduce the output signal?

 

The output of this TIA will be given to a comparator.The hysteresis is 100mV.If I can increase the output level it is well and good but I don't have negative rail available in my system.

 

My version functions better because the photodiode has a higher voltage and, as a result, a lower capacitance. I advise you to use a DC-DC negative voltage source..

 

DC-DC negative voltage,is good option to explore.I need to check my board space.This TIA adn Comparator are the extrathings in my borad version 2.If spce permits definitely I will consider providing dual supply.

May I know you have any suggestion for DC-DC negative voltage supply IC

 

See