SNOA963B February   2020  – July 2021 LDC2112 , LDC2114 , LDC3114 , LDC3114-Q1

 

  1.   Trademarks
  2. 1Inductive Touch Buttons – The Working Principles
    1. 1.1 Target Distance (DTARGET) and Sensor Size
    2. 1.2 Target Material
    3. 1.3 Target Thickness
  3. 2LDC211x and LDC3114 Gain Settings
  4. 3Threshold Configuration Process
  5. 4Example Application
  6. 5Summary
  7. 6Revision History

1.1 Target Distance (DTARGET) and Sensor Size

Inductive sensing relies on the interaction of EM fields generated by the inductive sensor and the eddy currents(2) being induced on the conductive surface. The amount of eddy currents induced on the target surface decreases with an increase in DTARGET as the target conductive surface now captures a smaller portion of the electromagnetic field generated by the inductive sensor. In turn, the physical size of electromagnetic field lines generated by an inductive sensing coil is directly proportional to the diameter of the sensor. Figure 1-2 shows how to set DTARGET as a percentage of the coil diameter for inductive touch.

GUID-6E638D0F-1AEC-4ED2-AF44-362D2941F5A1-low.pngFigure 1-2 Button Sensitivity as a Function of DTARGET
2. Refer to SNOA957 and SNOA930 for more information about eddy currents and LDC sensor design.