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FDC2112: how does FDC2112 obtain the LC resonant frequency?

Part Number: FDC2112

Hi team,

customer now want to learn how  FDC2112 obtain the LC resonant frequency. does it count the pulse and calculate the frequency? If so, does it use the maximum or minimum number of pulse?


  • Ruixin,

    The FDC2112 estimates the LC resonant frequency by counting the LC waveform's axis crossings over a time interval described in equation (5) in the data sheet:
    tcx = (CHx_RCOUNT x 16 + 4)/fREFx

    where CHx_RCOUNT is the number of reference clock cycles used to measure the sensor frequency for that channel, and fREFx is the reference clock frequency.

    For the FDC2112, the output data is related to the LC sensor resonant frequency via equation (1) in the data sheet.

    DATAx = fSENSORx x 212/fREFx

    John Miller