An interface IC for a capacitive silicon /spl mu/g accelerometer

High precision accelerometers with /spl mu/g resolution have numerous applications, including inertial navigation and guidance, microgravity measurements, and GPS-aided navigators. In all these applications, in addition to high resolution, the sensor module is required to have good dc response, low offset, and good offset and gain stability. This paper reports a capacitive interface chip for high sensitivity silicon accelerometers. It has 95 dB dynamic range, a low offset of 370 /spl mu/V, and 1/f noise cut-off frequency of <0.6 Hz. By using this IC in conjunction with an all-silicon accelerometer with 2O pF/g differential capacitance sensitivity an equivalent acceleration resolution of 3.7 /spl mu/g//spl radic/Hz can be achieved without a need for vacuum or special packaging. This IC can also be used for other high sensitivity capacitive silicon sensors.