Preface
1 LED and PWM
2 Schematic checklist:
This section provides a general checklist for touch applications. For application-specific information, please refer to the relevant topics or contact the Microchip Technical Support team.
3 Layout Guidelines
This section provides a general layout guidelines for touch applications. For application-specific information, please refer to the relevant topics or contact the Microchip Technical Support team.
4 Proximity Design Guide
5 Spring Sensor Guide
6 CAP Device
7 Metal Over Cap Guide
8 ITS
9 HOD
10 ESD Protection
Refer to the information below for general ESD protection guidelines related to touch applications.
11 EFT
Microchip Information

1.1 Cross- Talk

PWM can change a pin state from low to high during touch measurement. This state change can inject or remove charge to a nearby electrode or touch sense trace during the ‘share’ stage of touch acquisition. This is observed as noise in the touch signal. Isolating the PWM signal from the sensor and sense lines fixes this issue.

It is better to provide an edge-to-edge gap of more than two times the touch signal trace width between touch signal lines and PWM lines. Avoid running the touch sense trace and PWM trace in parallel.

Rev: A