Micromachined gyro takes signal processing onboard

The ADXRS MEMs-based gyroscope is the first commercially available device to integrate both an angular rate sensor and signal processing electronics onto a single piece of silicon.

The ADXRS MEMs-based gyroscope is the first commercially available device to integrate both an angular rate sensor and signal processing electronics onto a single piece of silicon.

By integrating the sensor structure and all necessary signal-conditioning circuitry onto a single integrated circuit, Analog Devices' iMEMS ADXRS gyro is smaller, more accurate, more reliable, and more economical than other angular rate sensors in its class.

The ADXRS gyro is mounted inside a small 7 x 7 x 3mm ball grid array (BGA) package, and consumes only 5mA at 5V.

This technological achievement was made possible by Analog Devices' iMEMS (integrated micro electro mechanical system) surface micromachining process - the same process that has been used to manufacture over 100 million accelerometers since 1993.

Gyroscopes are used to measure the rate at which objects rotate.

The information provided by gyros can be used to trigger automobile airbags during rollover, improve the accuracy and reliability of GPS/navigation systems, and stabilise moving platforms such as automobiles, airplanes, robots, antennas, and industrial equipment.

"Analog Devices' ADXRS gyro has a very low noise output which enables us to use it in many applications to augment GPS receivers where critical location information is required during temporary disruptions of GPS signals", said Michael S Perlmutter, Executive Vice President, Fibersense Technology, one of the world's leaders in advanced inertial navigation and stabilisation technology based in Canton, MA.

"In our product designs, reliability is critical and immunity to shock and vibration is a must.

Competitive solutions were not able to match Analog Devices in terms of size, performance or reputation for MEMS reliability".

For greater reliability assurance, the new device is also the only commercially available gyro with a full mechanical and electronic self-test feature that can operate while the sensor is still active.

By developing the new gyro on the iMEMS process, Analog Devices leverages over 10 years of MEMS manufacturing experience.

"Analog Devices is the industry leader in the MEMS accelerometer market today due in large part to the world class quality and reliability delivered by the iMEMS process", said Franklin Weigold, vice president and general manager of the Micromachined Products Division, Analog Devices.

"Using the iMEMS process, we can offer our customers a roadmap that will provide high quality, high performance gyros for as little as $10".

Patented design techniques that leverage the iMEMs process capabilities have resulted in a MEMS sensor that provides extraordinary immunity to shock and vibration.

The ADXRS gyro delivers stable output in the presence of mechanical noise up to 2000g over a wide frequency range.

This unique capability is important in applications such as automotive rollover detection, where a rollover event must be accurately detected while the vehicle is experiencing shocks and vibrations induced by collisions with other objects and off-pavement surfaces.

The ADXRS gyro is offered in two versions to accommodate different customer requirements for dynamic range.

The ADXRS300 provides dynamic range of 300deg/s, and the ADXRS150 provides dynamic range of 150deg/s.

Both are priced at $30 per unit in thousand piece quantities.

Samples are currently available and both products will be in full production by the end of 2002.

(This was Electronicstalk's Top Story on 2 October 2002).

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