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LDC1612-Q1: Position sensor sensitivity to the airgap change after calibration.

Jing Guo
Prodigy 10 points
Part Number: LDC1612-Q1
Other Parts Discussed in Thread: LDC1614-Q1

Tool/software:

Hi colleagues,

Here are a few questions about the IC performance.

A design using LDC1612-Q1/LDC1614-Q1 IC to sense a target moving. The travel distance is about 4mm, the travel direction is along the PCB board surface, the airgap between the target and the PCB surface is a constant value under ideal conditions.

After sample assembly and the sensor calibration:

1. How sensitive is the sensor to the airgap variation under vibration?

2. Is the sensing accuracy affected by unbalanced airgap?

3. Is the sensing accuracy sensitive to the ambient temperature, from -40C to +125C?

3. In a website source, https://www.ti.com/document-viewer/lit/html/SSZTCL3

    a. What does the code change mean? 

    b. What is the y-axis presenting?

Would anyone please provide some information that can answer the questions above?

Thank you.

  • 0
    TI__Mastermind 43870 points

    Hello,

    It sounds like you are talking about a linear type of sensing solution.  First, I recommend the app note below if you have not already seen it.

    https://www.ti.com/lit/an/snoa931a/snoa931a.pdf

    1. See table 3 of the app note.  This shows different tolerances and how it will affect the results.

    2. There will be some dependence on temperature.  In general, a higher Q coil results in higher noise immunity and lower dependence on temperature.  The device internal oscillator has some dependence on temperature, but the coil itself is more likely a bigger factor.  High Q and PCB based coils are recommended for good stability over temperature.

    3. The code change is referring the to ADC codes that are output by the LDC device.  The Y axis is showing the change in ADC codes per 0.1mm step.