LDC0851EVM: LDC-Tool and oscilloscope evaluation

Hello Zhihao,

We will try to have some feedback for you on this issue later this afternoon.

Hello Zhihao,

On page 1, your approach matches what we have in our appnote (snoa930c, Sensor Design for inductive Sensing
Applications).

On page 2, the final inductance is calculated through the product of the initial no target inductance and an inductance scaling factor that is based on the sensor diameter closest target distance.  The scaling factor equation is actually quite complex with several constants.  Where the constants are derived from I cannot tell.

For your other pages, I will try to take another look at those the next business day.

Hello Patrick,

Thank you for your help with my previous issues.

As meantioned on page 1 of the appnote, do you know how to calculate the flux linkage k? It states that k depends on the distance between the coils. Could you please provide more details on how to calculate it?

I look forward for the response.

Additionally on page 2, thanks for clarifying the function of the LDC0851_calc tool. However, I am still unsure why the 20mm coil lies in the limited area. Could you please expain this further?

Hello Zhihao,

Per the inductance value estimated by the scaling factor, it is smaller than the inductance calculated by formula (7) in the datasheet.

Hi Patrick,

Patrick Simmons said:

Per the inductance value estimated by the scaling factor, it is smaller than the inductance calculated by formula (7) in the datasheet.

So the inductance value calculated with the LDC0851_calc is smaller then the formula (7): Lsensor >= 1/(4.83*fsensor*Isensor_max). Did I understand it correctly? 
 

Yes,  the value calculated from the sensor diameter and closest target distance leads to a value less than the Lsensor value calculated by that Lsensor formula.