GENERAL DESCRIPTION
FEATURES
S Low Average Operating Current (100µA at 14V) S 1.2.fF LSB Capacitance-to-Digital Resolution (5pF MAX1441 During manufacturing, JTAG programming uses four digital I/Os. The device uses grounded electrode capacitive sensing to measure capacitance between one of the two sense pins and the ground. A hand approaching a sense electrode attached to these sense pins causes a change in measured capacitance indicating the presence (touch or proximity) of the object. Activeguard outputs shield the sense electrode from unwanted sources without adding parasitic capacitance. Spread-spectrum techniques in the sensor excitation circuit reduce both electromagnetic emissions and susceptibility to interfering signals. In addition, the sensing excitation frequency is programmable from 100kHz to 500kHz in 10kHz steps to avoid interference. The sensor input signals are converted to a 12-bit digital data and are available to an on-chip microcontroller (FC). The device provides independent offset compensation of up to 63pF for each input channel.
Maxim Integrated
