Guidance on hardware for TSI

[MAPC]

We are developing a keyboard for electric ovens, using the MC9S08PT60 TSI.

We took a look at the app note AN3863 and saw some grounding and shielding tecniques.

And we are wondering what are the best tecniques for this kind of application:

1) No grounding or shielding over electrodes area

2) Only shield nearby electrodes

3) Only hatch ground plane on the bottom

4) Both

Could anybody give us some advice, tips, etc?

Note: It is an ordinary 12-key keyboard with acrylic overlay. All the system is integrated in one 2-layer board.

Thanks!

[reyes]

Hi Marco,

The recommendation for a 12-key keyboard integrated in a 2-layer board, would be your options 2 and 3, place shield nearby the electrodes and use hatch ground plane on the bottom of the electrodes area.

Regards,

Jose