3 Replies Latest reply on Jun 1, 2016 11:25 PM by user_1377889

    Probing capsense and shield signals

    sravan.mettupalli

      Hey guys,

         

      I'm working on a product with a proximity sensing loop, and a driven shield on the backside to direct sensitivity in a single half of the pcb plane.

         

      I'm trying to figure out if my CMod capacitor is sized properly for my application. Here's a scope capture, Chan1 is the sensor signal, and chan2 is the driven shield. Is this what it is supposed to look like?

         

       

         

      The application notes and reference manuals said to 'make sure CMod is fully charging and discharging' but it didn't specify what the voltage is or what the waveform should look like--so guidance is appreciated.

         

       

         

      [Image attached] also uploaded here: http://i.imgur.com/DlMw2Xy.png