OPA855: 1 GHz APD receiver circuit design advice using the OPA855

hello, 

Your C1 needs to be 0.27pF for stability, doing that will yield a Butterworth response with 830MHz F-3dB. 

Hello Hyeonjoong Son,

  I agree with Michael. You may be able to push it to closer to 900-950MHz cutoff frequency, but you will lose phase margin and it will alter your response (Q factor). 

  Layout is key to very high speed applications. I would recommend looking at our FAQ page under the transimpedance amplifier circuit section where we have popular threads, content, and calculators. 

    I also recommend reviewing this thread where Kai goes into detail about layout for TIAs using the OPA855. The most important aspect is to keep the photodiode as close to the input terminal of the amplifier as possible to avoid oscillations/instability due to board parasitics. 

Thank you,

Sima

Thanks for the detailed advice. Where can I use the calculator in the attached photo?

Hello Hyeonjoong Son,

  Here is a link to the TIA calculator: https://e2e.ti.com/support/amplifiers-group/amplifiers/f/amplifiers-forum/956151/faq-transimpedance-amplifier-calculator

  Let me know if you run into any questions!

Thank you,
Sima

Wow, thank you for a very useful tool. Have a great day!!!