Dear Technical Support Team,
I have two question about shield of FDC1004. Customer have follwoing touch sensor.
Touch electrode > Iron plate(GND)
It has a parasitic capacitive between Touch electrode and Iron plate(GND). So they'd like to eliminate a parasitic capacitive with shield.
Touch electrode > Shield > Iron plate(GND)
In my recognition, generaly CapSensor IC drives Touch electrode and Shield with same phase. So Touch electrode(V1) and Shield(V2) are V1=V2 and capacitance eliminated from Touch electrode and Iron plate(GND). (Capacitance is available, but V1=V2 situation dosen't cause current flow to the capacitance)
1.) "Capacitive Sensing: Ins and Outs of Active Shielding" shows following figure for shield. Dose it means above my recognition? If my recognition is wrong, could you give me some advice?
2.) FDC1004 datasheet shows " Shield Drive Capability (Typ) (pF) : 400". Dose it mean that if CPAR is over 400pF, it causes V1≠V2 and shield dosen't affect capacitance eliminated?
Best Regards, y.i
