A fully integrated Gm-Coscillator forreadout ofaforce balanced accelerometer

A tunable 2MHz to4MHz CMOS sinusoidal oscillator forreadoutofa forcebalancedcapacitive accelerometer ispresented. Amplitude stability ofthe carrier isconsidered alongwithfrequency stability ina temperature rangefrom-40'Cto+85'C.Frequency and amplitude aretunedwithbinary weighted capacitor arrays. Amplitude related frequency drift iscompensated using PTAT (Proportional To Absolute Temperature) current reference. A buffer amplifier operating inan openloop configuration compensatesthe temperaturerelated amplitude drift. Simulated 6% amplitude stability and10 % frequency stability withinthetemperature rangeis achieved. Simulation results arepresented inthis paper.