Datasheet

For best EMC performance the circuit should be made entirely with SMT components.

Electrode trace routing: Keep the electrode trace (and the electrode itself) away from other signal, power,

and ground traces including over or next to ground planes. Adjacent switching signals can induce noise

onto the sensing signal; any adjacent trace or ground plane next to, or under, the electrode trace will

cause an increase in Cx load and desensitize the device.

Bypass Capacitor: Important – For proper operation a 100 nF (0.1 μF) ceramic bypass capacitor must be

used directly between Vdd and Vss, to prevent latch-up if there are substantial Vdd transients; for

example, during an ESD event. The bypass capacitor should be placed very close to the VSS and VDD

pins.

4.5 Power On

On initial power up, the QT1012 requires approximately 250 ms to power on to allow power supplies to

stabilize. During this time the OUT pin state is not valid and should be ignored.

Note that recalibration takes approximately 200 ms, so the QT1012 takes approximately 450 ms in total

from initial power on to become active.

AT42QT1012

Datasheet

DS40001948A-page 23