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ADS1298: Use of Bipolar/unipolar supplies and Shield drive

keval dalwadi
Prodigy 80 points
Part Number: ADS1298

Hello,

AS we know ADS1298 have provision for unipolar and bipolar supply.So my question is, why we need bipolar supply in ECG and does it have any pros and cons over unipolar?? One another question is for shield drive. Can you Please explain why we need shield drive???

Thanks.

  • 0
    TI__Guru 63196 points
    Hello Keval,

    Thanks for your interest in our ADS1298!

    You don't "need" bipolar supplies for ECG applications, but the advantage to using them is that input signals are allowed to swing below ground. From the ADC's perspective, the performance will be exactly the same whether you use bipolar or unipolar supplies.

    The shield drive is used to reduce the parasitic capacitance of the electrode cable shielding to the inner cable which carries your ECG signals. The shield should be driven to the same common-mode voltage as the input signals in order to minimize this capacitance and prevent unwanted noise from coupling onto the cables.

    Best Regards,
  • 0 in reply to Ryan Andrews
    Prodigy 80 points

    Hello,

    Can you please give a comprehensive answer on, in which case we use Bipolar supply over Unipolar supply?? and what if we do not give bipolar supply to differential amplifier connected with Shield drive??? we are using anti-aliasing RC filter between DB connector and ADS how can we select the value of R and C.?

    Thanks