FDC2214: How to improve the sensitivity of FDC2214

Hi Rock,

The sensitivity is a function of sensor size, device configuration, and target characteristics. Your hand is a much larger target than a drop of water, which is likely why you are seeing such a large difference in the responses to the two targets. The maximum resolution for a given sensor can be achieved when using the largest RCOUNT register value, though this will yield the slowest sample rate.

Unfortunately the device can only measure shifts in the frequency of the LC tank due to shifts in sensor capacitance, so it is unable to determine what kind of target changed the capacitance. This means that there's no way to make the sensor more sensitive to water without also making it more sensitive to all other targets. If there's no chance of other targets influencing the sensor, this may be okay for your customer's application.

Could you tell me a bit more about your customer's application? If it is a liquid-level sensing application, we have many application notes that can help.

Regards,