Posted on January 16, 2014 at 22:25The shield pin is used to drive an active shield (also called driven shield) plane.
The principle of a driven shield is to drive the shield plane with the same signal as the
electrode. There are several advantages of using a driven shield instead of a grounded one:
o The parasitic capacitance between the electrode and the shield no longer needs to be
charged. This offers an optimum sensitivity.
o A driven shield is useful for certain applications where shielding may be required to:
– Protect the touch electrodes from a noise source
– Remove touch sensitivity from the cable or track between the electrode and the
sensing MCU.
– Increase system stability and performance when a moving metal part is close to
the electrode.
If you need further information, I invite you to have a look to the AN4312.
What exactly does marking a pin as SHIELD do?
