4-Ch, 12-bit, capacitance to digital converter

Capacitive sensing is a low-power,

high-resolution contactless sensing technique that can be applied to a variety of

applications ranging from proximity detection and gesture recognition to remote

liquid level sensing. The sensor in a capacitive sensing system is any metal or

conductor, allowing for a highly flexible system design.

The main challenge limiting

sensitivity in capacitive sensing applications is noise susceptibility of the

sensors. With the FDC2x1x resonant sensing architecture, performance can be

maintained even in the presence of fluorescent light.

The FDC2x1x

is a multi-channel family of high-resolution, high-speed capacitance-to-digital

converters for implementing capacitive sensing solutions. The devices employ an

innovative narrow-band based architecture to offer high rejection of out of band

noise while providing high resolution at high speed. The devices support a wide

excitation frequency range, offering flexibility in system design. A wide frequency

range is especially useful for reliable sensing of conductive liquids such as

detergent, soap, and ink.

The FDC221x is optimized for high

resolution, up to 28 bits, while the FDC211x offers a fast sample rate of up to

13.3kSPS for easy implementation of applications that use fast moving targets. The

large maximum input capacitance of 250nF allows for the use of remote sensors, as

well as for tracking environmental changes over time such as temperature and

humidity.

The FDC2x1x family targets proximity

sensing and liquid level sensing applications for any type of liquids. For

non-conductive liquid level sensing applications in the presence of interferences

such as human hands, the FDC1004 is recommended and features integrated active

shield drivers.