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OPA855: transimpedance amplifier - bandwidth, gain and ripple of the output signal

Stefan Korolczuk
Prodigy 10 points
Part Number: OPA855
Other Parts Discussed in Thread: OPA858,

I am trying to develop a transimpedance amplifier for SiPM/MPPC silicon photomultipliers. I need wide bandwidth and low gain. I developed a system based on OPA855. In practice, OPA858 seems to be a better solution, but in both cases I have a problem with fast pulses. Is there an effective method to eliminate the effect of signal ripple without sacrificing bandwidth?
Regards, Stefan

  • 0
    TI__Genius 15001 points

    Hello Stefan,

    I am looking over your system.  I can also take a look at our resources and see if I can provide some pointers on your question about reducing signal ripple.  You are correct about tradeoffs, but we can find a solution with tolerable compromises.

    Is there a maximum amount of ripple the design/system can tolerate?  What are your bandwidth needs?

    I am making the assumption your simulation values for Cin are selected to reflect your end-use SiPM.

    Best,

    Alec

  • 0 in reply to Alec Saebeler
    Prodigy 10 points

    Hello Alec,

    The silicon photomultiplier will be optically coupled to the scintillators. Key signal parameters:
    - the pulse rise time is often less than 10 ns.
    - pulse fall time approx. 100ns
    - preservation of the pulse shape - discrimination of neutron/gamma radiation due to the pulse shape.
    - wide range of observed signal amplitudes

    Currently, I use two types of SiPMs: S13361-3050NE-04 from Hamamatsu and AFBR-S4N44P164M from Broadcom. All elements are connected in parallel.

    Increasing the feedback resistance would limit the amplifier's bandwidth, which would help in this case, but:
    - SiPM operates as one cell with high gain, which produces significant current
    - to improve the parameters of the SiPM signal, it is recommended to increase its voltage, which additionally increases the SiPM gain

    These limitations essentially limit the gain of the transimpedance amplifier.

    I have an additional question: if there is no simple solution, how can I effectively and repeatably limit the amplifier's bandwidth without increasing its gain?

    Regards,
    Stefan

  • 0 in reply to Stefan Korolczuk
    TI__Genius 15001 points

    Hello Stefan,

    Thank you for the system details.  I will dig into your extra question and see if I can find a way.

    Best,

    Alec