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MSP430FR2633: Captivate with NFC R/W

na na78
Guru 16770 points

Part Number: MSP430FR2633

Hi

Please see the following file.

3276.e2e_v1.xlsx

As you can see in the file, the customer is considering Capacitive touch with Captivate surrounded by antenna of NFC reader/writer.
Could it be possible to be interfered between NFC R/W and capacitive touch each other with such board layout?

Could you please give me your view?
I appreciate if I could get feedback from your team. (Or NFC team)

BestRegards

  • 0
    TI__Guru 71216 points

    Let me check with our NFC experts.

  • 0 in reply to Dennis Lehman
    TI__Intellectual 2885 points

    Hallo,

    we do have several customer applications where the buttons are surrounded by the NFC antenna. It does not seem to be a problem.

    Test with NFC antennas (around 25x25mm and 50x50mm) and 3 small buttons seem to work well for both systems without mutual interference.

    It depends also on the protocol and the power of the NFC device (standard ICs in the market with about 200mW).  In worst case our technology provides the capability to change the operation band (we recommend 4 or 2 MHz or any value 16MHz/x, where x is between 2 and 64). Being in the 2-4MHz range you should be far enough from the carrier and the sub-carrier (848kHz). In addition, the operation of the NFC read and touch scan can be synchronized by SW.

    What is the size of you antenna and the button?

    Regards

    Kostas

  • 0 in reply to Kostas Aslanidis
    TI__Intellectual 2885 points

    Sorry, the pics are missing in the first response.

    Regards

    Kostas

  • 0 in reply to Kostas Aslanidis
    Guru 16770 points

    Hi Kostas

    Thank you for your reply.

    The size of antenna is not fixed.   Want to read Felica/Mifare in range of 0~50mm.
    The sizes of touch button is over φ10mm.

    > In worst case our technology provides the capability to change the operation band (we recommend 4 or 2 MHz or any
    >value 16MHz/x, where x is between 2 and 64). Being in the 2-4MHz range you should be far enough from the carrier and
    >the sub-carrier (848kHz). 

    Is there no influence by changing operation band frequency for reading Felica/Mifare?

    BestRegards

  • 0 in reply to na na78
    TI__Intellectual 2885 points

    Hallo,

    it's hard to say what would be the influence of the CapTIvate operating frequency as it depends on other parameters too like distance, layout, NFC read cycles etc.

    Normally once you have set the CapTIvate frequency to the right band which does not influence the NFC, it will not change over time.

    I would suggest that you do a quick test with existing HW to test the mutual influence of both systems.

    Basically similar to the pics above.

    Use an existing NFC reader and place the electrode within the antenna area. The electrode can be a simple cooper foil connected to the FR2633 IO.

    Generate a simple CapTIvate project using Captivate Design Center and let both systems run.

    This is a simple way to check the basic operation and performance. Of course for the final implementation and layout you must follow the design recommendations given by TI.

    I am interested to see the results.

    If you have any questions, please feel free to contact the e2e forum.

    Best regards

    Kostas

  • 0 in reply to Kostas Aslanidis
    Guru 16770 points

    Hi Kostas

    Thank you for your reply and suggestion.

    I will consider it.

    BestRegards

  • 0 in reply to na na78
    TI__Intellectual 2885 points

    My pleasure,

    please feel free to contact the forum if you have questions.

    Regards

    Kostas

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