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ADS1220: ADS1220 : possible measure against ESD/Surges/Impulse noise perturbations

Karcel Zabieru
Prodigy 85 points
Part Number: ADS1220
Other Parts Discussed in Thread: ADS8686S

Tool/software:

Dear TI,
we are using your great ads1220 product with 8-channels inputs with RTD pt100 3-wires temperature sensors on our design and the PCB is working great.
Lately we did some EMC impulses/surges/esd tests injecting 2kV on the 100VAC-24VDC input and possibly getting some noise on the 3-wires pt100 lines and/or around the ads1220.
We followed the reference design for power decoupling and layout organization and ground planes around in the inner layers of the design.
We were wondering if there is any recommendations or measure we could add to protect the ads1220 from external perturbations that could lead to glitches on the ADC measure values.
My best regards,
Zabieru.

  • 0
    TI__Expert 7770 points

    Hi Zabieru,

    I'll reach out to our team to see if we have any data on this and if there are any recommendations we can make to help with EMC.

    Best Regards,

    Angel

  • 0 in reply to Angel Rodriguez de San Miguel Bermudez
    Prodigy 85 points

    Dear Angel,
    thanks for your continuous support and you supporting my questions about the ads1220 product we are using. I will reply to you if any further elements needed.
    Best,
    Zabieru.

  • 0 in reply to Karcel Zabieru
    TI__Expert 7770 points

    Hi Zabieru,

    Still looking into this. Will reach back early next week with updates.

    Best Regards,

    Angel

  • 0 in reply to Angel Rodriguez de San Miguel Bermudez
    TI__Expert 7770 points

    Hi Zabieru,

    Unfortunately, we don't have additional EMC/ESD data specific to the ADS1220 other than what is stated on the ESD ratings on the data sheet:

    There is an "EMC Compliance Testing for Precision ADC Systems" app note with some EMC tests ran on the ADS8686S, which you may find useful.

    It demonstrates external protection circuitry designed on each analog input to protect the ADS8686S from electrical overstress (EOS) failure, and also surge (IEC61000-4-5), electrostatic discharge (ESD) (IEC61000-4-2), electrical fast transient (EFT) (IEC61000-4-4) transient signals.

    Best Regards,

    Angel

  • 0 in reply to Angel Rodriguez de San Miguel Bermudez
    Prodigy 85 points

    Dear Angel,


    like always thanks a lot for your reply and support about your products.
    Thanks for sharing informations and AN names.


    From a surge (IEC61000-4-5) standard point of view, it seems that the ads1220 is ready until 2kV which seems normal as it should not be exposed directly on surge from outside.
    One question/concerns is about external Pt100 3-wires sensor, I guess the wires should be shielded to prevent noise from the surge passing close-by. Do you have any other recommandations about the external sensor connexion ?

    ADS8686S device and AN are very interesting and show the TI state-of-art rules to prevent ESD issues and I noticed in the schematic R//C circuit between IGND and E-GND which should be copied in our design to prevent surge coming from E-GND to the digital GND or digital VCC feeding the ads1220.

    If some models about those isolations R//C circuits exist at TI, I would be interested to use and test them to see the possible results towards our design.

    Much regards,
    Zabieru.