Design & Manufacture
Analog – Safety-critical auto applications benefit from iMEMs gyroscope vibration immunity (ADXRS800)Sep 7 2011 - Design & Manufacture [More Design & Manufacture Articles]
For automotive electronic stability control, rollover detection, and pitch detection applications, Analog Devices has introduced the ADXRS800 iMEMS gyroscope, featuring a patented differential quad-beam architecture designed to minimize the influence of linear shock and vibration. Qualified for automotive safety applications, the ADXRS800 is the most stable, vibration-immune automotive-grade gyro available while a continuous electro-mechanical self-test feature ensures the integrity of the gyro output signal, says the company.
“A stability control system needs accurate inertial signals at all times, especially when harsh vibrations and shocks are present,” said Thomas Wessel, vice president, Automotive, Analog Devices. “Safety critical auto applications like this benefit greatly from the ADXRS800’s vibration immunity. The continuous self-test feature is also key to realising fail-safe system performance according to the highest industry standards. The innovations that this part delivers will make cars safer.”
Unlike alternative MEMS gyros, the ADXRS800’s ‘unique’ architecture enables very 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°/sec/g, vibration rectification is only 0.0002°/sec/g2, noise-rate density is 0.02°/sec/√Hz at +105C and null offset variation is 3°/s maximum over temperature and product life. Further simplifying the system design, the gyro delivers better offset stability compared to alternatives without the need for calibration. What’s more, power consumption is only 6 milliamps under typical conditions. The new gyro is available in a cavity plastic SOIC-16 (Z-axis) and a SMT-compatible vertical mount package (X-axis) and is capable of operating across an extended temperature range of -40C to 125C.
The ADXRS800’s continuous self-test architecture simplifies algorithms for failure detection and allows system designers to quickly integrate fault detection into their 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 base band that can be filtered so it does not interfere with sensor output. The ADXRS800 is capable of sensing angular rates up to ±300°/sec while providing high resolution of 80 LSB/°/s on the low end due to its wide dynamic range and low noise of 0.16°/s rms with a 80Hz filter. Angular rate data is presented as a 16-bit word, as part of a 32-bit serial peripheral interface (SPI) message. Other features include internal temperature compensation over an extended industrial temperature range and an optional ceramic vertical-mount package that uniquely enables three-axis sensing on a single PCB without daughter boards, says the company.
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