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Original question:

ADS1293: ADS1293 RLD and Common MOde

ADS1293: Reduce common mode interference without RLD electrode

Freddie Olsson
Prodigy 10 points
Part Number: ADS1293


Hello,

I'm working on the same product as my college was previously talking about over here:

https://e2e.ti.com/support/data-converters-group/data-converters/f/data-converters-forum/1160969/ads1293-ads1293-rld-and-common-mode

Where we have LL, LA and RA, but no RLD-electrode. We are currently digging deeper into the CMMR and how to implement it without a RLD-electrode.

The suggested solution was to use the internal MUX to route the RLDOUT-signal to IN1 to IN3. I fail to see how this would work, since the RLDOUT signal should be low impedance and the INX very high impedance. However, i see a possiblity to do bias each INX channel with a fixed external resistor to RLDOUT. As i see it this would close the loop for the CM signal and still allow the ECG signals through. Would this be a possible solution?

  • 0
    TI__Mastermind 19815 points

    Hi,

    I will try to get back to you by 3/3.

    Thanks

  • 0 in reply to ChienChun Yang
    TI__Mastermind 19815 points

    Hi,

    Do you happen to have an evaluation kit/board(EVM)?

    ----------------------------------------------------------

    The suggested solution was to use the internal MUX to route the RLDOUT-signal to IN1 to IN3. ......." since the RLDOUT signal should be low impedance and the INX very high impedance. "

    That's how RLDOUT could bias.

    ---------------------------------------------------------

    For "However, i see a possiblity to do bias each INX channel with a fixed external resistor to RLDOUT."

    It's possible, but not necessary.  Customers could try above two different methods and compare the results.

    And, It's suggested to use an EVM board to do some tests&evaluation.

    And, Designers&developers will need to do tests&experiments, data collection&analysis and V&V before making decisions.

    Thanks