I am going to lay out a minimal board for the ADuCM350, primarily focusing on the AFE and SPI sections. My AFE will be measuring a high-impedance sensor. For minimizing coupled noise, what are your recommendations as far as un-used pins (i.e. leaving them floating vs. grounded, etc.)? Also, for unused sections (e.g. the cap-touch sensor, the LCD, the USB, which have their own labeled power and ground pins) what do you recommend as far as connecting those sections' power and ground pins and/or capacitors across them?