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ADC WITH BETTER INPUT REFERRED NOISE THAN 1UVPP

WhiteHorse
Genius 4430 points
Other Parts Discussed in Thread: ADS1299

e2e,

We have a customer that is interested in the ADS1299 for digitizing bio-potential signals on the surface of the body (such as in EEG).  They would like a lower Input Referred Noise specification than 1uVpp.  They need 8 analog inputs and they must be simultaneous sample.  I don't see any current product with these features and lower  Input Referred Noise.  Is there one planned for the future?

Thanks for your help.

Regards,

John Wiemeyer

  • 0
    TI__Mastermind 23275 points
    Hi John,

    we do have ADCs that offer lower noise than 1uVpp but unfortunately none of them would be simultaneous sampling. There is nothing on the roadmap today.
    Would they be open to use multiple discrete ADCs in parallel and synchronize them using the same clock for all of them?
    If yes, what data rate are they asking for and what would be the full scale signal they need to measure (this will determine the max gain we could use).

    Regards,
  • 0 in reply to Joachim Wuerker
    Genius 4430 points
    Thanks Joachim, Checked with customer and they prefer not to use multiple ADCs at this time. They may change their mind in the future. They didn't give me their signal levels, but did say sample rate is 20ksps.

    Thanks for your help.
    Regards,
    John Wiemeyer
  • 0 in reply to WhiteHorse
    TI__Mastermind 23275 points
    Hi John,

    the ADS1299 can only sample as fast as 16kSPS when using the internal oscillator. Are they sure about the 20kSPS?
    There is no data converter on the market available today - as far as I know - that can achieve 1uVpp noise performance at 20kSPS.

    One option to improve the noise performance with ADS1299 (or any ADC) would be to implement a moving average filter in their MCU/DSP.

    Regards,
  • 0 in reply to Joachim Wuerker
    TI__Expert 4620 points
    Dear e2e Community,

    I have a similar request and would like to know if our ADS1299 is always the best solution for low noise.

    Regards,
  • 0 in reply to TISL
    TI__Mastermind 23275 points

    Dear TISL

    the ADS1299 is our lowest-noise ADC for those specific biopotential measurement applications.
    We have even lower noise ADCs but they will not offer 8 ADCs within one package. The right ADC choice will depend on your application needs. If you can share some details about what you are trying to do I can probably point you to the most suitable ADC.

    Regards,

  • 0 in reply to Joachim Wuerker
    TI__Expert 4620 points
    Hi Joachim,

    The application is an in-ear EEG, which requires very low noise signal chain, as the signal is 4x time smaller than standard EEG .

    Regards,
  • 0 in reply to TISL
    TI__Mastermind 23275 points
    Hi TISL,

    how many channels do you need to measure (simultaneously) in an in-ear EEG and what output data rates do you require?
    Also is this a battery powered application where power consumption is critical?

    Regards,