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ADS1291: Can I use 2 electrode (ADS1291) for 1-Lead ECG include RLD?

Jason Chien42
Expert 1180 points
Part Number: ADS1291

Dear Sir:

               We used ADS1291 for 1-LEAD ECG application. As below picture , ADS1291 have MUX to switch RA/LA/RLD. Can we used 2 electrode to measure 1-Lead ECG include RLD function? 

  • 0
    TI__Guru 66466 points

    Hello Jason,

    Thanks for your question.

    To measure 1-lead, you will need a minimum of two measurement electrodes (i.e. RA and LA). RLD is not for ECG measurement, but rather for establishing the DC common-mode voltage on the body as well as improving CMRR for unwanted AC signals. If you only want to have two electrodes in your application, the channel inputs will need to be AC-coupled, and you will need to bias the input pins another way.

    Check out this video training series to learn more about different ECG electrode configurations:

    https://training.ti.com/how-measure-ecg-guide-signals-system-blocks-and-solutions

    Best Regards,

  • 0 in reply to Ryan Andrews
    Expert 1180 points

    Dear Ryan:

                 Thanks for your reply. As I know , 1-Lead ECG usually used 2 electrode(RA/LA) to measure ECG and used third electrode for RLD. We want to clarify that  ADS1291 can used 2 electrode to measure 1-lead ECG + RLD ? Or  it need through internal MUX to switch IN2P/IN2N pin to connect third electrode for RLD function?

    Best Regard

    Jason

  • 0 in reply to Jason Chien42
    TI__Guru 66466 points

    Hi Jason,

    Thanks for clarifying. The RLD amplifier in the ADS1291 has its own dedicated output pin (RLDOUT). You can use this pin as your RLD output signal and connect it to your RLD electrode with proper protection circuitry in place, just like the Channel 1 inputs.

    You do not need to route the RLD through the MUX in your typical application setup, but there is an option to do so. For example, in systems with multiple leads, the MUX can be configured to reroute the RLDOUT to one of the channels inputs whenever the RLD electrode is disconnected. This feature is explained in more detail on page 50 (REROUTING THE RIGHT LEG DRIVE SIGNAL).

    Best Regards,