Sense finger dynamics in a Σ∆ force-feedback gyroscope

This paper presents a gyroscope that uses Σ ∆ force-feedback for closed-loop Coriolis-acceleration sensing and 1-bit digital output. The noise floor is approximately 3º/s/¥Hz at atmospheric pressure. The effect of capacitive sense-finger resonance on the Σ ∆ feedback loop is analyzed. In order to minimize quantization noise the resonant frequency of the sense fingers should be designed above fs/4, if the sense and feedback electrodes are separate. If the same electrodes are used for sensing and feedback, the finger resonance should be designed near fs/6, where fs is the sampling frequency