Extending the Capacitive Input Range of the AD7746 Capacitance-to-Digital Converter

Extending the Capacitive Input Range of the AD7746 Capacitance-to-Digital Converter. This circuit provides a method to extend the capacitive input range of the AD7746. How to use the on-chip CapDAC sufficiently in order to minimize the range extension factor and, therefore, optimize the circuit to achieve the best possible performance is also explained. The AD7745 has one capacitance input channel, while the AD7746 has two channels. Each channel can be configured as single-ended or differential