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Bipolar supply scheme connection

Oscar Baumann
Intellectual 835 points
Other Parts Discussed in Thread: ADS1298

I need information how can i configure the ads1298 for use in bipolar mode.

My question is the following, there are a lots of pins AVSS AVDD those pins have the same configuration that show in datasheet on page 75?

The other question if I have to separate AGND DGND. 

Thanks 

  • 0
    TI__Guru**** 181021 points

    Hi Oscar,

    To use the ADS1298 in bipolar mode, you can take Figure 73 from page 75 and tie the AVDD pins to your positive rail, the AVSS pins would go then to your negative rail.  These are typically +/-2.5V with the center point being your 'AGND'.  Your DGND needs to be referred to this node which effectively ties AGND and DGND together.  Using Figure 73, the digital supply can range from 1.65 to 3.6V to accommodate your host controllers digital I/O requirements.

  • 0 in reply to Tom Hendrick
    Intellectual 835 points

    HI Tom, thanks for your answer.

    Tom I have another question I read a medical guide fo texas and it said that the medical equipment trend to use unipolar supply. Why?

    If I use unipolar supply I will have more, less or equal noise? I really want to know all diferences between use unipolar or bipolar supply, advantage or disadvantage.

    I really apreciate yoru suggestion.

    Thanks.

     

  • 0 in reply to Oscar Baumann
    TI__Guru**** 181021 points

    Hi Oscar,

    Would you mind letting me know which medical guide you are referring to?  From the perspective of noise, have a look at this app note:

    http://focus.ti.com/lit/an/sbaa160a/sbaa160a.pdf

    That might get you started from the perspective of unipolar versus bi-polar supplies.  I'll look around and see what additional advantages/disadvantages I can come up with on one approach versus the other.