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MKW30Z Capacitive touch TSI pin circuit

Question asked by Lucian Firan on Feb 27, 2017
Latest reply on Apr 21, 2017 by Lucian Firan

KW40Z_Connectivity_Software_1.0.1 (KSDK_1.3.0); IAR 7.50;

On a MKW30Z requiring one pin for capacitive touch TSI sensing circuit PTC3 muxed to TSI0_CH15

 

The TSI plate is not mounted on PCB, but via a small coax cable less than 10 cm to a brass metal knob on the metal case isolated from the case.

 

The reference article AN3863: Designing Touch Sensing does not give references for outside pcb sensors.

http://www.nxp.com/assets/documents/data/en/application-notes/AN3863.pdf 

 

There are some specifications on how to adapt the button ?

Pull-up resistor is required ?

There is a need for additional parallel capacitance ?

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