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Original question:

FDC2x1x Confirmation of principle

FDC2214: FDC2x1x Confirmation of principle

Benedikt Funke
Prodigy 10 points
Part Number: FDC2214

Hello,

I was wondering, how the FDC2214 generates Fsensor. I am trying to evaluate the capacitance at different Fref via an external clock. DATAx changes accordingly, but Fsensor seems to be a constant. How can I change Fsensor?

Many thanks

  • 0
    TI__Genius 17440 points
    Hi Benedikt,

    The FDC2214 automatically drives the sensor at the resonant frequency of the LC tank. If nothing is interacting with the capacitive sensor (and therefore changing the capacitance of the LC tank), the resonant frequency of the LC tank will not change, so Fsensor will stay constant. If you wish to change Fsensor you will need to either change the inductor in the LC tank or have a target interact with the capacitive sensor.

    Also note that in general, a higher frequency Fref will yield better resolution. This is because the output codes of the FDC2214 are a digital representation of the ratio Fsensor/Fref.

    Regards,