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FDC2214EVM: Technical Query regarding FDC2214 EVM - active shield

Part Number: FDC2214EVM
Other Parts Discussed in Thread: FDC2214, BUF634, FDC1004

Hello TI technical support team

 

We are experimenting with FDC2214 EVM to use it in one of our projects as capacitance to digital converter.  

 

We want to use the system for unidirectional sensing, since FDC2214 doesn’t have any active shield driver it cannot be used for the same. We tried the method mentioned in following link to implement an active shield driver. However, no changes were observed in the response even after using BUF634 op-amp (as unity gain amplifier).

 

https://e2e.ti.com/support/sensors-group/sensors/f/sensors-forum/551536/fdc2214-active-shield

 

This is the design we followed as per the link. Could you please advise if there is any other design which we can follow to implement active shield driver and use FC2214 EVM for unidirectional sensing?

                                                             

  • Arpitha,

    The link you mentioned is all that we have for this topic for the FDC2xxx family.
    If this is a problem with an inadequate shield driver, please consider the FDC1004.
    The FDC1004 has an internal, built-in shield driver that does not require additional parts.

    Regards,
    John

  • Hello John

     

    Thank you for your response.

     

    We have already tested FDC1004, but it does not satisfy the range requirement in our use case.

     

    FDC2214 EVM has better range, but only requirement is to make it unidirectional. Following the design of BUF634 op-amp (as unity gain amplifier) as posted in the forum did not make any difference in the response.

     

     

    Could you please suggest any other solution for this issue? Or if you have other capacitor to digital converter model, which has built-in active shield driver with range of about 75-100cm.

  • Arpitha,

    The FDC1004 is the only capacitive sensor we have with an active shield driver.

    Regards,
    John