photodiode amplifier

Dear all

I want built a photodiode amplifier.Its bandwidth need over 100MHz to observe a pulse train.

I use photodiode wizard(PHOTODIODE | Analog Devices) and follow their suggestion.

But I test the circuit and there's a strange oscillation(as attachment) and exist when I block my photodiode.

How to solve this problem?
  • 0
    •  Analog Employees 
    on Jul 15, 2015 5:21 PM

    Dear Yung-Cheng,

    Have you read AD8015 datasheet? It is in website.

    AD8015 is a complete TIA design for telecommunication applications.

    It might be OK to support your applications at certain application scenarios.

    Best Regards,

    Dongfeng Zhao

  • Dear Donfeng

    Yes,I plan to use IC AD8015 recently.

    But I have some questions for using AD8015.

    According to AD8015 datasheet

    Do I only need to connect my photodiode to pin2 ,+5V to pin8 and pin7 will output the signal?

    Does the photodiode frequency response performance only decided by IC design?

    Does there any recommended circuit to my case?


  • 0
    •  Analog Employees 
    on Jul 15, 2015 5:46 PM

    Dear Yung-Cheng,

    AD8015 datasheet has some typical applications circuits. For example, Fig. 3 and 4 are concept

    ideas of how to connect a PIN photo-diode to AD8015 at positive or negative biased scenarios.

    Best Regards,

    Dongfeng Zhao

  • Dear Dongfeng

    The part I don't understand is what's the fiber optic receiver means?

    Are the Quantizer and clock recovery be necessary for use this IC?

    The signal I want is RL*I(t).

    So does this IC satisfied my needs?


  • 0
    •  Analog Employees 
    on Jul 16, 2015 4:50 AM

    Hi Yung-Cheng,

    The AD8015 may be a good option, but I am curious why the circuit the photodiode wizard generated for you using the ADA4899-1 and AD8011 is not working for you.

    Some questions that might help to debug the circuit:

    1) Are the power supplies for the ADA4899 and AD8011 bypassed with 0.1 uF capacitors?

    2) What does the signal at the the ADA4899-1's output look like?

    3) If you remove the photodiode completely from the circuit, does the oscillation go away?

    4) Can you double check that Cf, the 3.9pF capacitor, is indeed soldered correctly?

    5) If you change Cf to a larger value, say 10 pF, does the oscillation change?