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Need for an instrumentation amplifier and a copatible high-pass filter for the EVAL-AD7177-2SDZ board

Category: Hardware
Product Number: EVAL-AD7177-2SDZ, AD7177-2

Hello, for my upcoming project, I've purchased the EVAL-AD7177-2SDZ.

Looking at the datasheet and based on the signal I've obtained, the front-end present on the board does not seem suitable for the acquisition of the EEG signal, which is subjected to high noise sources and has low amplitudes (μV).

I'm searching for a possible board compatible with the EVAL-AD7177-2SDZ composed of:

  • a programmable gain instrumentation amplifier (PGIA) that has:

    • low offset voltage of 0.5uV

    • rejects common signals with 120dB

    • adjustable gain around 10/20 (The gain cannot be set too high due to the DC component)

  • and by a high-pass filter used to remove the DC voltage offsets (cutoff frequency (-3dB) approximately 0.05Hz).

In conclusion, my acquisition circuit should be composed of:

  • PGIA

  • high pass filter

  • ADA4528-2A (present in the EVAL-AD7177-2)

  • AD7177-2 (present in the EVAL-AD7177-2)

  • digital filter (present in the EVAL-AD7177-2)

Any suggestions or advice would be greatly appreciated.

Top Replies

    •  Analog Employees 
    Apr 5, 2024 in reply to Ana20009 +1 verified

    Hello  ,

    As Kristine mentioned, the lowest Vos that we have in our inamp portfolio is 10uV. However, we do have several traditional inamps that are used for biopotential applications such as: AD8235…

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  • Hi Ana20009,

    Unfortunately, our lowest Vos PGIA is around 14uV and lowest in the whole in-amp portfolio is around 10uV. For PGIAs I would suggest ADA4254/55 for that low offset(14uV) and high CMRR(126dB) but we really haven't seen this applied to EEG signal acquisition. If you are open to non-PGIA options, we may have several parts targeted for that application.

    Regards,

    Kristine

  • Hi Kristine Hoffman,

    Thank you for your quick reply.

    I have purchased the EVAL-AD7177-2SDZ as a possible solution for acquiring EEG signals, but it does not seem suitable for this purpose according to my results. Do you have any suggestions for improving the front end of the board? Also, could you specify the various parts targeted for this application that you mentioned?

    Any suggestions would be greatly appreciated. Thank you very much.

    Regards,

    Anastasia

  • Hello  ,

    As Kristine mentioned, the lowest Vos that we have in our inamp portfolio is 10uV. However, we do have several traditional inamps that are used for biopotential applications such as: AD8235/7, AD8220, AD8420. 

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