topic Re: MPR03x pad shape/area in Sensors

MPR03x pad shape/area

onechil — Wed, 17 Dec 2014 20:47:48 GMT

The app. note in the link below suggests suggests that "The minimum pad size for Freescale’s products is 3 mm by 3 mm when using thin film overlays to about 0.5 mm thickness of acrylic or ABS plastic".

In a proximity sensing application, assuming the area of the object to be sensed is >= 9mm sq. and the profile of the object is planar to the sensing electrode pad on a PCB, is it accurate to interpret the 3mm x 3mm recommendation, as a 9mm sq. minimum electrode pad area for Freescale's touch sensing products?

Thanks,

Re: MPR03x pad shape/area

Joshevelle — Wed, 17 Dec 2014 22:40:13 GMT

Hello onechil,

Yes.

Proximity sensors like the MPR03x sense changes in the Electrode Capacitance, which is related to the electrode's area. We suggest a minimum of 3x3mm which equals to 9mm sq area. So yes, you shouldn't have any issues.

Hope it helps.

Josh

Re: MPR03x pad shape/area

onechil — Wed, 17 Dec 2014 22:44:54 GMT

Hi Joshevelle,

Sounds good! I thought as much, but wanted some clarification, cheers.

Re: MPR03x pad shape/area

Joshevelle — Wed, 17 Dec 2014 22:45:51 GMT

You're welcome. Have fun!

Josh

Re: MPR03x pad shape/area

onechil — Wed, 17 Dec 2014 23:28:14 GMT

Actually I have one more question - I haven't been able to find a recommended PCB footprint for the MPR03x uDFN part. Would you be able to refer me to one? Thanks.