Inertial sensors rapid prototyping for automotive application

Automotive market is craving for always cheaper and more performing sensors, to be employed in numerous electronic controls, from the standard ABS to futuristic Adaptive Cruise Control. Nowadays, MEMS sensors have been embraced by the auto industry in their quest to improve performance, reduce cost, and enhance the reliability of the sensing system; yet they require more complicated signal processing at the electronic interface stage. ISIF (Intelligent Sensor InterFace) is a powerful Platform On Chip, developed by SensorDynamics AG, in 0.35 mu m BCD technology, aiming to fast prototype a wide range of automotive sensors, as it provides a highly programmable set of analog and digital IPs, trimming options and by flexible routing structures and the possibility to extend processing resources with software DSP, replicating the behavior of hardware IPs. In this way ISIF can fast prototype a new sensor interface straight in its application field, drastically shortening the development time of full-hardware optimized sensor interfaces. This paper presents an application of the ISIF chip for conditioning a gyroscope and a dual-axis low-g accelerometer in MEMS technology. In spite the short prototyping time, the resulting system achieves good performances with respect to commercial devices, featuring a gyroscope with a sensitivity of 20 mV/degrees/s and a rate noise of 0.4 degrees/s and an accelerometer with a 0.9 mg/root Hz noise density with 1024 LSB/g sensitivity on the digital output over a +/- 2g FS, and an offset drift over 100 degrees C range within 30 mg, with 2% of FS sensitivity drift.