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LMP7721MAEVALMF_NOPB: LMP7721 Evaluation Board Railing for a long period of time

Part Number: LMP7721MAEVALMF_NOPB

Hi TI Engineers!

I purchased a couple of LMP7721 Evaluation boards (4 or 5) and I noticed they all shared the same issue. When the LMP7721 is railed, it will take a around 300 seconds to get to an un-railed value. The LMP7721 is setup in a transimpedance amplifier configuration with a feedback resistor of 5T and capacitance of 2pF. When the op amp is not railed, the time response is close to R*C of the configuration. I'm using the evaluation board to measure charged particles. Is there an explanation for this phenomena? 

Thanks!

Tyler

  • Hi Tyler,

    Could you share more about your application and how you are measuring the charged particles and the conditions in which you observe this 300 second overload recovery time? I presume you are using the transimpedance configuration shown in the evaluation board's user guide, but if you could share your schematic showing what everything is set to and what you are interfacing with this would be very helpful.

    Regards,

    Zak Kaye
    Precision Amplifiers Applications 

  • In reply to Zak Kaye:

    Zak,

    Sorry for the wait. Here is my configuration:

    Are you suggesting that this is not a common LMP7721 issue; however, it could be something with my experimental setup? If that's the case, then I'm satisfied with that answer!

    Thanks,

    Tyler

  • In reply to Tyler Bershad:

    Hi Tyler,

    I apologize but with the holidays I did not see your reply until now. Were you able to determine the cause of the 300 second overload recovery time?

    Regards,

    Zak Kaye
    Precision Amplifiers Applications 

  • In reply to Zak Kaye:

    I got it! Thanks a bunch!

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