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Webench coil designer

Håkon Hodne
Prodigy 50 points
Other Parts Discussed in Thread: LDC1612

Hi,

I have designed a coil using webench with parameters as shown below. Testing the physical coil with LDC1612 eval.kit gives different values; Inductance=513uH and sensor frequency 324kHz. Why?

  • 0
    TI__Genius 13335 points

    Hello,

    The combination of 513µH and 470pF yields a sensor frequency of approximately 324kHz which looks to be exactly what you measured.

    The formula for calculating the oscillation frequency is f = 1/ (2π * √(L*C) ).

    For the discrepancy between the webench tool approximation and the real life measurement, I would first verify that all of the parameters you entered above are actually what was manufactured. For instance, I notice that you've changed the spacing between the layers to be x12=0.415mm, x23=0.7mm, x34=0.415mm, however when the tool exports the CAD file it doesn't change these parameters. It defaults to x12=x23=x34=0.32mm. This would increase the expected inductance from what the tool predicted. From experience, we have found that the webench tool quite closely matches the bench measurements.