Noise analysis and characterization of a sigma-delta capacitive silicon microaccelerometer

This paper reports a high-sensitivity low-noise capacitive accelerometer system with one micro-g//spl radic/Hz resolution. The system operates as a 2/sup nd/-order electromechanical /spl Sigma/-/spl Delta/ modulator together with the interface electronics. A detailed noise analysis of electromechanical /spl Sigma/-/spl Delta/ capacitive accelerometers with a final goal of achieving sub-/spl mu/g resolution is also presented. The circuit has more than 120 dB dynamic range and can resolve better than 10 aF. The complete module operates from a single 5V supply and has a measured sensitivity of 960 mV/g with a noise floor of 1.08 /spl mu/g//spl radic/Hz in open-loop. This system can resolve better than 10 /spl mu/g//spl radic/Hz in closed-loop.