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ADS1298: ads1298

neuron stim
Prodigy 100 points
Part Number: ADS1298
Other Parts Discussed in Thread: , ADS1299

Hi..

I want to design an EEG signal acquisition with ads1298 . and I don't have any idea with analog filter for ADS1298 inputs.

Should I put an analog filter before ads1298 or not?
Should the signal be amplified before ads198 or not?

Thanks for your guidance.
  • 0
    TI__Guru 55152 points

    Hi,

    Yes, an anti-aliasing filter is recommended on the inputs. For an example filter, please see the schematic in the user's guide of the ADS1298ECGFE-PDK: http://www.ti.com/tool/ADS1298ECGFE-PDK

    Typically, pre-amplification is not recommended as the input referred noise of the gain amplifier will be multiplied by the gain and reduce the SNR of the measurement. If higher performance is desired, I recommend considering the ADS1299, which has very low input-referred noise and is ideal for EEG measurements.  

  • 0 in reply to Alexander Smith
    Prodigy 100 points

    Hi.

    Thank you Alexander .

    Can you take a look at this schematic and see if there is a problem or not?

    I have some problem with analog and digital ground .As you can see ,I connected the two with a indicator. is it correct?

    and are the input filters correct or not?

    and for power I used 2cell Lithium-ion battery and  tow LP2950-3.3v  for analog and digital supply.

    Thanks for your help.

  • 0 in reply to neuron stim
    TI__Guru 55152 points

    Hi, 

    My pleasure. Overall, things look very good. I would recommend connecting the two ground with a 0ohm resistor instead of an inductor. The inductor may impede some return currents from returning to the source. The filters are correct as well. 

    You may want to get another opinion from someone one the power forum for your battery circuit as I am not an expert in this area.