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Maximal sampling frequency with LDC 1041 and a 1mili Henry inductor

Yoni Mandel
Prodigy 60 points
Other Parts Discussed in Thread: LDC1041

Hi,

I'm trying to use the LDC 1041 in order to measure the change in the inductance of a coil, between 1.4 to 1.6 mili Henry.

Can you advise me which parameters should I be using in order to receive a sampling rate (output data rate) of 20KHz and a resolution of 10 micro Henry?

Thank you, Yoni.

  • 0
    TI__Expert 6550 points
    Hello Yoni,

    The resolution is determined by 1/(# of counts). You could either obtain the Fcount value from the Frequency Counter Data register, or calculate it according to the formula given on page 12 of the datasheet.

    Best Regards,
    Natallia Holubeva
  • 0
    TI__Genius 14270 points
    Hi Yoni,
    For the LDC1041 devices, the sample rate is a function of the sensor frequency. To hit 20ksps, the lowest sensor frequency would need to be 1.28MHz. For a sensor frequency of 1.28MHz with a 1.4mH inductor, your sensor capacitance would need to be approx 12pf, which is quite low and may expose you to a inaccuracies from parasitic capacitance. In addition, it is entirely possible that the coil may have a self-resonance frequency well below 1.28MHz; in which case the sensor may not even work at such a frequency. Is it possible to reduce the inductance?
    Regards,ChrisO