How to structure GND & SHIELD [slider+proximity]

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ViWa_4121741
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Hi,

First of all congratulations for your community.

I would like to know how to define every part in my layout. I have a seven segments linear slider surrounded for a proximity sensor. My question is:

Q1: I found in the design guidelines that two more GND segments should be added at the beginning and at the end of the slider, is it necessary if I add a GND hatched plane? If the hatched plane is used for the shield electrode is necessary these GND segments? (I will implement two mount/no mount  0ohms resistors to have both options)

Q2: I found that the proximity sensor needs a ground loop around, but i didn't found anything about the inside of the proximity. In my case, the slider will be inside the proximity sensor, so the hatched plane (SH or GND) of the slider could interfere with the proximity sensor?

Have any advice to create the layout with both solutions would be great,

Thank you

Victor

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Hari
Moderator
Moderator
Moderator
750 replies posted 500 replies posted 250 solutions authored

Hi viwa_4121741

1. It is recommended to add two more dummy segments at top and bottom to obtain a linear response from the slider. The connection to these segments depends on the inactive sensor configuration of the CapSense component.

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If this is selected as ground, the dummy segments must be connected to ground.

2. It is recommended to use shield inside the proximity sensor as this will result in lower parasitic capacitance and therefore, better sensitivity.

Please refer Proximity Sensing with CapSense for more details on design.

Thanks and regards

Harigovind

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