The AD7142ACPZ-500RL7 is an integrated Capacitance-to-Digital Converter with on-chip environmental calibration for use in systems requiring a novel user input method. It can interface to external capacitance sensors implementing functions such as capacitive buttons, scroll bars or wheels. It has 14 inputs channelled through a switch matrix to a 16-bit and 250kHz sigma-delta capacitance-to-digital converter. The CDC is capable of sensing changes in the capacitance of the external sensors and uses this information to register sensor activation. The external sensors can be arranged as a series of buttons, as a scroll bar or wheel or as a combination of sensor types. By programming the registers, the user has full control over the CDC setup. High resolution sensors require minor software to run on the host processor. It has on-chip calibration logic to account for changes in the ambient environment.
Programmable capacitance-to-digital converter
Better than 1fF resolution
No external RC tuning components required
Automatic conversion sequencer
On-chip automatic calibration logic
Automatic compensation for environmental changes
Automatic adaptive threshold and sensitivity levels
