ISSCC 2004 / SESSION 17 / MEMS AND SENSORS / 17 . 3 17 . 3 A 2 . 5 V 14 - bit Σ ∆ CMOS - SOI Capacitive Accelerometer

Low cost high precision MEMS accelerometers with near μg resolution and stability are needed in a number of applications ranging from GPS-augmented inertial navigation systems to guidance and stabilization of satellites and spacecrafts [1]. This paper presents a truly 14b Σ∆ modulator interface IC for a highresolution SOI capacitive accelerometer fabricated in a simple stictionless process that improves the performance and manufacturability of high-sensitivity accelerometers. The interface IC is designed and fabricated in the 2.5V 0.25μm 2P5M N-well CMOS process provided by National Semiconductor and interfaced with the accelerometer chip using wire-bonds. Power consumption is 6mW including an on-chip multiphase clock generator for data sampling. The measured resolution of the accelerometer system is 110μg at 75Hz with a 1Hz resolution bandwidth (RBW) and dynamic range of 85dB. The resolution is limited by the sensitivity of the accelerometer.