Here is some information on how to design CapSense sensors while developing Capacitive sensing applications in MBR 3xxx.
After selecting MBR3 device, while designing schematic you can refer to the following documents:
1) MBR3 datasheet (http://www.cypress.com/file/46236/download )
2) CapSense schematic design section in AN90071 - MBR3xxx CapSense Design Guide (http://www.cypress.com/file/46366/download)
While designing PCB, refer to the following documents:
1) While designing any CapSense sensor, you can refer to MBR3 design Toolbox (http://www.cypress.com/file/46361/download) to decide on the sensor dimensions.
2) CapSense layout guidelines section in AN90071 - MBR3xxx CapSense Design Guide (http://www.cypress.com/file/46366/download)
3) Design considerations section in AN64846 - Getting Started with CapSense (http://www.cypress.com/file/41076/download)
Following the above mentioned guidelines in various documents will help achieve high SNR, better performance and electromagnetic compatibility.
Feel free to leave comments and ask questions, we appreciate the feedback!