The FDC2112, FDC2114, FDC2212, and FDC2214 are high-resolution, multichannel capacitance-to-digital converters for implementing capacitive sensing solutions. In contrast to traditional switched-capacitance architectures, the FDC2112, FDC2114, FDC2212, and FDC2214 employ an L-C resonator, also known as L-C tank, as a sensor. The narrow-band architecture allows unprecedented EMI immunity and greatly reduced noise floor when compared to other capacitive sensing solutions.

Using this approach, a change in capacitance of the L-C tank can be observed as a shift in the resonant frequency. Using this principle, the FDC is a capacitance-to-digital converter (FDC) that measures the oscillation frequency of an LC resonator. The device outputs a digital value that is proportional to frequency. This frequency measurement can be converted to an equivalent capacitance