Question: What are the design guidelines for using Flex PCB instead of FR4 PCB for CapSense designs?
You need to follow two important guidelines when using a Flex PCB for your CapSense design:
- You may need to use a slower CapSense clock, because the resistance per square inch for Flex is higher.
- Do not use a hatched ground below your sensor. Flex PCB is much thinner than FR4 PCB, and a hatched ground will increase parasitic capacitance.
Refer to the design guide Getting Started with CapSense for more design guidelines.