AD7142

FEATURES Programmable capacitance-to-digital converter 36 ms update rate (@ maximum sequence length) Better than 1 fF resolution 14 capacitance sensor input channels 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 On-chip RAM to store calibration data SPI®-compatible serial interface (AD7142) I2C®-compatible serial interface (AD7142-1) Separate VDRIVE level for serial interface Interrupt output and GPIO 32-lead, 5 mm x 5 mm LFCSP_VQ 2.6 V to 3.6 V supply voltage Low operating current Full power mode: less than 1 mA Low power mode: 50 μA APPLICATIONS Personal music and multimedia players Cell phones Digital still cameras Smart hand-held devices Television, A/V, and remote controls Gaming consoles GENERAL DESCRIPTION The AD7142 and AD7142-1 are integrated capacitance-todigital converters (CDCs) with on-chip environmental calibration for use in systems requiring a novel user input method. The AD7142 and AD7142-1 can interface to external capacitance sensors implementing functions such as capacitive buttons, scroll bars, or wheels. The CDC has 14 inputs channeled through a switch matrix to a 16-bit, 250 kHz sigma-delta (∑-Δ) capacitance-to-digital converter. The CDC is capable of sensing changes in the capacitance of the external sensors and uses this information to register a sensor activation. The external sensors can ...