High precision open-loop and closed-loop MEMS accelerometers with wide sensing range

摘要

This paper presents two high performance wide sensing range MEMS accelerometers, built using different techniques. The paper comprises two sections. In the first section, open-loop accelerometers with up to 40 g sensing range and 18 bit dynamic range are presented. In addition to a discussion on design, statistically based test results are demonstrated. In the second section, a closed-loop sigma-delta accelerometer with 30 g sensing range and 21 bit dynamic range is presented, including a short design review and test results from the most recently fabricated batches. Our open-loop accelerometers have demonstrated tactical grade performance featuring 0.5 ppm of full range/√Hz noise, 100 ppm bias stability, and 0.5 % of full range nonlinearity. Our closed-loop accelerometer, designed to compete with traditional macro electro-mechanical quartz accelerometers, features <;10 μg bias instability, 0.1% typical nonlinearity over full 30 g sensing range, and less than 100 μg/grms2 Vibration Rectification Error (VRE) up to a 2 kHz frequency range. Both open-loop and closed-loop sensors represent a fully integrated system comprising a uniquely designed MEMS device enclosed in a specially built LCC package with a proprietary ASIC.