A wide-range micromachined threshold accelerometer array and interface circuit

This paper presents a complete threshold acceleration detection microsystem comprising an array of threshold accelerometers and a low power interface circuit. The sensors were designed and fabricated using the bulk-silicon di ssolved-wafer process. The process offers a wide latitude in sensor thresho ld levels, as demonstrated in the fabrication of devices with levels of 1.5 -1000 g, bandwidths of 45 Hz to 30 kHz, with mass sizes ranging from 0.015 mug to 0.7 mug, and low-resistance gold-gold contacts for the switch. The i nterface circuit dissipates less than 300 muW, measures 2.2 mm x 2.2 mml it was fabricated in-house using a standard 3 mum, p-well CMOS (complementary metal oxide semiconductor) process, and is connected to the sensor chip in a multi-chip module. The key aspects of the microsystem are the implementa tion of sensor redundancy and supporting circuit logic to improve detection accuracy and fault tolerance, which are crucial factors in many applicatio ns. In addition, the microsystem supports communication with a standard mic rocontroller bus in a smart sensor network.