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ads1292 for cloth design

Patrick Chen
Mastermind 8875 points
Other Parts Discussed in Thread: ADS1292

Hello,

               Customer would like a cloth design. They prefer use patch with cable for sensing ECG and maybe will pass through connector to ADS1292. They hope to know what is minimum ECG signal maybe 10uV,20uV....etc before ADS1292 under this topology? Do we have any reference data for ECG signal by cloth design? Thank you. 

BR

Patrick  

  • 0
    TI__Mastermind 38745 points

    Hi Patrick,

    Unfortunately we do not have any reference data for that type of design. However, I wouldn't get hung up on the type of material. The more important thing to consider is the contact impedance of the electrode. Since there are small currents that get drawn at the inputs to the ADC, an IR drop will be exhibited across the body-electrode boundary. If that contact impedance is high, then an offset could be produced that limits how high the input signal can be gained in order to get the necessary voltage resolution to find the ECG data. The contact impedance will depend not only on the type of material, but also on the surface area and quality of the connection. I would advise looking into those things as well when considering a type of electrode.

    In terms of the ADS1292's ability to resolve small signals, it is a 24-bit ADC with an internal programmable gain amplifier with a gain as high as 12. The LSB size for any particular configuration depends on the reference voltage. As an example, if the internal 2.42 V reference is used with the PGA gain equal to 12, then 1 LSB will be approximately equal to 24 nV. The size of the noise floor can depend on the PGA gain and the converter data rate as well as the cutoff frequency of any external low-pass filter that the customer is using. Hopefully this explanation was a good guide for the next steps in your design.

    Regards,

    Brian Pisani