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Transimpedance Amplifier for Photocurrent

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tongkin

New Member
Greeting,

I would like to use Transimpedance Amplifier to convert the current from photodiode into voltage signal. Is it possible to design without inductor and capacitor?

If yes, can anyone tell me how? Or do you know where to have it?

Thank you.
 

crutschow

Well-Known Member
Most Helpful Member
Basically you just connect the photodiode to the inverting (-) input of an op amp with a feedback resistor between that input and the op amp output. The output voltage equals the diode current times the feedback resistor value.

But to avoid peaking of the signal versus frequency you will need a small feedback capacitor in parallel across the feedback resistor, typically several pF in value.

What frequency response and gain do you need?
 

tongkin

New Member
Thank you for your reply,

I forgot to say that I would like to design in transistor level including OP circuit. Is it possible to design without any capacitor and inductor?
The BW requirement is not high, just above 100MHz is ok, and the gain is above 114dBohms.


Besides, if I use operational transresistance amplifier(OTRA) to implement TIA for photodiode, is it work?

Thank you,
 

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crutschow

Well-Known Member
Most Helpful Member
Designing a transistor level OTRA is a very difficult task, requiring experience in high frequency circuit design, layout and detailed transistor knowledge. And 100MHz is a high frequency for such a circuit. It is certainly not a project for a beginner. And whether you need a capacitor or inductor to build the circuit is the least of your worries.
 

tongkin

New Member
Designing a transistor level OTRA is a very difficult task, requiring experience in high frequency circuit design, layout and detailed transistor knowledge. And 100MHz is a high frequency for such a circuit. It is certainly not a project for a beginner. And whether you need a capacitor or inductor to build the circuit is the least of your worries.

Thank you for your suggestion,
I think, I will take other's OTRA circuit to use in my project.
My problem is "Is the characteristic of OTRA can be use to convert the photocurrent signal into voltage signal?"

Thank you,
 

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