For automotive electronic stability control, rollover detection, and pitch detection, the ADXRS800iMEMS gyroscope is from Analog Devices. It has a patented differential quad-beam architecture designed to minimise the influence of linear shock and vibration. The continuous self-test architecture simplifies algorithms for failure detection and allows system designers to integrate fault detection into designs. The integrity of the electromechanical system is checked by applying a high frequency electrostatic force to the sense structure allowing differentiation from real-rate stimulus in the baseband that can be filtered, so it does not interfere with sensor output. The gyroscope senses angular rates up to ±300°/sec while providing high resolution of 80LSB/°/s and low noise of 0.16°/s rms with a 80Hz filter. Angular rate data is presented as a 16bit word, as part of a 32bit SPI message. The gyroscope is qualified for automotive safety applications and is claimed to be the most stable, vibration-immune automotive-grade gyroscope available. A continuous electro-mechanical self-test feature ensures the integrity of the output signal. The architecture is claimed to enable accurate performance in exceedingly harsh automotive environments without the need for complex and costly, system-level counter measures. Sensitivity to linear acceleration is specified at only 0.03°/s/g, vibration rectification is only 0.0002°/s/g2, noise-rate density is 0.02°/s/√Hz at 105°C and null offset variation is 3°/s maximum over temperature and product life. The company also claims that it delivers better offset stability, compared to alternatives, without the need for calibration. Power consumption is just 6mA, under typical conditions. The gyroscope is available in a cavity plastic SOIC-16 (Z-axis) and a SMT-compatible vertical mount package (X-axis) and operates across an extended temperature range of -40 to 125°C.
