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ADS1299: Re: Noise testing, ADS1299

Sushant Rajbhar
Prodigy 90 points
Part Number: ADS1299


Hello Team,

 We have developed a custom device for EEG measurement using ADS1299 IC.

We are into a dilemma about the test options mentioned in the ADS1299 EVK user manual.

For part 8.1 i.e. On-Chip (ADS1299) Input Short test, the noise should be less than 1uV (p-p).

However for device when we are measuring the same using the same register settings as described in section 8.1, we are getting a noise of around 1.45uV(p-p).

Here comes the question:

Please let us know whether the noise obtained in EVK (1uV) is filtered or raw signal (unfiltered)?

If the noise is a raw signal (unfiltered), then we would like to reduce the noise further in our device.

Can TI help us to with some tips to reduce the noise further?

Best Regards,

Sushant Rajbhar

  • 0
    TI__Genius 11550 points

    Hi Sushant,

    The shorted input noise should be approximately 1uVpp for PGA=24 and DR=250SPS (refer to Table 4 in datasheet). It is the raw and unfiltered data. The possible noise sources are from the reference, power supplies, or a poorly layout PCB. Since the input is shorted internally, the noise coupling from the input is insignificant. Are you using the internal 4.5V reference or external reference? It is also essential to have all the recommended decoupling capacitors for the device.

    Thanks

    -TC