An accelerometer interface circuit

This paper presents an interface circuit which converts the femtofarad-level signal from an accelerometer's capacitive sense element to a pulse signal suitable for digital signal processing. Calibration circuitry compensates for the offset and sensitivity variations in the sense element and for packaging variability. The circuit has been fabricated in a 1.6 /spl mu/m CMOS process. Test results show very low sensitivity to variations in temperature or supply voltage.