OPA855: Use OPA855 to design a TIA

Hi,

please see section 10.2 of datasheet.

Are you sure that your APD has a detector capacitance of 320pF? Or is it 320fF?

Kai

Hi uer6343584,

Kai's question may be correct. Assume di=700nA, dt=2nsec, C=320pF, the dV= i*dt/C = 4.375uV, which is very slow light sensor response. 

Anyway, enclosed is TIA application note for your reference. It is fairly simple circuit and you may input the circuit into Tina for simulation. 

http://www.ti.com/lit/an/sboa268a/sboa268a.pdf?&ts=1589903106735

Best,

Raymond

Thank you for your answer. I have another question. How do I configure the signal source to represent APD when I simulate in TINA-TI? For example, the current size is 700nA, 2ns. Is it correct that I use the current generator, select the pulse, and then directly input the amplitude of 700n and the pulse width of 2n?

Thank you for your answer. I have another question. How do I configure the signal source to represent APD when I simulate in TINA-TI?For example, the current size is 700nA, 2ns. Is it correct that I use the current generator, select the pulse, and then directly input the amplitude of 700n and the pulse width of 2n?

Here is the circuit diagram of my preliminary design. In this picture, the waveform of my instantaneous analysis does not achieve the desired effect. What is wrong with the design here?

5282.Noname.TSC

The instantaneous analysis I said is Transient.The output wave is not my desire.

user_opa855.TSC

Kai

Can you tell me what parameter were you changed to take this wave? I haven't see any changes. Thanks a lot.

Hi uer6343584,

Thanks for Kai's simulation. 

Please see the error and setting that are revised below. 

Best,

Raymond 

Yes, exactly. Thanks Raymond :-)

Kai

From the results of your simulation, the output signal is superimposed with a DC voltage.

If I want to filter out the DC voltage of this signal, should I add a filter circuit after this circuit? Is there any reference design or amplifier?

Thanks.