CapSense_Gap with the ground hatch

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hata_3396041
Level 4
Level 4
First solution authored First like received 50 questions asked

Hello

Please tell me about the design of CapSense.

According to the design guide,"the gap between the sensor pad and the ground hatch should be equals to the overlay thickness".(MAX 2mm)

https://www.cypress.com/file/46081/download (P.94)

If there is no space on the board,is it not a problem to make this gap 1.5mm?

Sensing method  ・・・CSD

Sensor pad diameter・・・8㎜

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1 Solution

Tanaka-san,

Very sorry for my late!

3mm acrylic overlay is OK for button's design, but not good for touchpad design.

In this case, for buttons pattern,  1.5mm gap from GND is OK for getting a good sensitivity.

Best Regards,

Ryan

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5 Replies
RyanZhao
Moderator
Moderator
Moderator
250 sign-ins First question asked 750 replies posted

Tanaka-san,

What is the thickness of the overlay?

In general cases, there is no problem to use 1.5mm gap. However, that depends actual situation.

For example, if overlay is too thick but sensitivity requirement is high, no GND around the sensor could be better.

Thanks,

Ryan

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Ryan-san,

Thank you for your reply.

The thickness of the overlay is 3mm and the material is acrylic.

Thanks

Tanaka

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Ryan-san

I'm sorry to bother you.

Is there no problem with 3mm overlays?

Thanks

Tanaka

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Tanaka-san,

Very sorry for my late!

3mm acrylic overlay is OK for button's design, but not good for touchpad design.

In this case, for buttons pattern,  1.5mm gap from GND is OK for getting a good sensitivity.

Best Regards,

Ryan

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Ryan-san

I understand.

Thank you for your help!!

Thanks

Tanaka

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