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ADS1299-4: Looking for a more affordable alternative to the ADS1299

Ken Schmahl
Prodigy 50 points
Part Number: ADS1299-4
Other Parts Discussed in Thread: ADS1299, , BQ25570, ADS1294, ADS1194

I'm not satisfied by the cost of the ADS1299 in our design. I'm charged with cost-reducing the board, and this part is top of the list.

I'm looking for a TI apps egr or sales egr to help replace their own part before I kick it out for an Analog Devices part.  The challenge, always, is to get the attention of a TI engineer. I'm betting no one is paying attention -- prove me wrong.

thanks, ken

  • 0
    TI__Guru**** 168445 points
    Hi Ken,

    Welcome to our e2e Forum! There are pin compatible alternatives to the ADS1299, with lower resolution and different sample rates. What performance characteristics can you give up?
  • 0 in reply to Tom Hendrick
    Prodigy 50 points

    Thank you Tom!  I’m delighted to get a quick response.  Previous experiences have been disappointing.

    I’m using the internal clock at 2MHz for EEG studies. Low-noise is a must. I don’t want to limit options beyond that.  What’ve you got? :-)

    Ken

  • 0 in reply to Ken Schmahl
    TI__Guru**** 168445 points
    Hi Ken!

    Not sure what your previous experiences have been, but this seems to be the first time you've visited the e2e Forum. Hopefully we can change things up for you a bit. If low noise is your key concern, it's going to be tough to move away from the ADS1299-4 for EEG applications. Give us a little time to go through the portfolio and see what we can do.
  • 0 in reply to Tom Hendrick
    Prodigy 50 points

    I, and others here at Flex's Innovation Labs, have had bad experiences trying to get any support from TI FAEs.  I speak of a design I did Spring of 2017 using the bq25570.  I don't see a record of my forum posts.  That is odd, agreed.

    At any rate, I'm grateful for your help, Tom!  Now I wish I could change the subject line a bit.

    I'm reviewing the ADS1294 which is similar to the ADS1299-4.  It's got higher input-referred noise but lower cost.  Does it also sample all channels simultaneously?

    thanks again,

    Ken

  • 0 in reply to Ken Schmahl
    TI__Guru**** 168445 points
    Hi Ken,

    I can edit the subject line for you - let me know what you want it to say! To answer your question though, yes, the ADS1294 does sample all channels simultaneously. I was actually going to suggest that, or the ADS1194, but when you mentioned noise was still a top concern, I started exploring other avenues. Unfortunately these are the only parts we have to offer at the moment that would be lower cost replacements for the ADS1299-4.
  • 0 in reply to Tom Hendrick
    Prodigy 50 points
    Subject line: ya, please:
    "ADS1299-4: Looking for a more affordable alternative to ADS1299"
    A much more polite subject line :-)
    My apologies -- I pulled out my big guns right from the start; inappropriate.

    I'll take a look at the ADS1194, but if I remember right its noise is higher than the 129x.

    Question on Biopotential Measurements:
    Are cardio signals much higher than EEG, or brain, signals? TI's cardio devices, like the 129x, seem to be more tolerant to noise, implying that EEG is a smaller signal and needs much lower noise. I'm researching this question on the web this afternoon.

    Thanks,
    ken

    p.s. we'll mark this done after your reply to my cardio question.
  • 0 in reply to Ken Schmahl
    TI__Guru**** 168445 points

    Hi Ken,

    Great question! The amplitude of the EEG is about 100 µV when measured directly on the scalp, and about 1-2 mV when measured sub-cranial, which is right around the same magnitude as typical ECG signals.

  • 0 in reply to Tom Hendrick
    TI__Mastermind 46290 points

    Hi Ken,

    The subject line also caught my attention. I hope Tom and I can convince you that you have the full support of TI :)

    Please feel free to ask any questions here, and expect a response :)

  • 0 in reply to Kevin Duke
    Prodigy 50 points
    Thanks Kevin. Honestly, there were some real problems 18 months ago. But I should have given you and your team the benefit of the doubt and not burned the subject line right out of the gate. I do apologize. Tom responded quickly and was a great help.

    And thank you for your note as well. At the current level of integration, and with the breadth of specialties we (Innovation Labs) touch, we design engineers are very much dependent on the expertise of a vendor's FAEs. I'm delighted to see TI's level of support. Thank you, once again!

    Kind regards,
    Ken Schmahl, P.E.
    Flex International
    Silicon Valley Innovation Center (previously called "Innovation Labs")