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Micro Gyroscope Puts A New Spin On Price

By Matt Kelly
Small Times Correspondent

Oct. 1, 2002 -- It's been a long time coming, but this week Analog Devices delivered what product engineers have anticipated for years: an affordable, self-contained Micro-Electro-Mechanical Systems (MEMS) gyroscope.

Known as the ADXRS, the gyroscope is commercially available starting this week. Analog spent six years developing the product, a gyro that will sell for as little as $10 and lead to a host of new market uses.

Analog Devices already dominates the market for accelerometers, the first and still largest application for MEMS devices. Company officials are confident they can leverage the Analog name and its manufacturing prowess to seize momentum in the market for gyros as well.

"We can provide our customers a roadmap that will provide high-quality, high-performance gyros for little as $10," said Frank Weigold, general manager of Analog's MEMS division.

The ADXRS gyro is mounted on a ball-grid array package, 7 millimeters square and 3 millimeters thick. It consumes 5 milliamps of power at 5 volts, small enough to put the gyro in handheld computers and other battery-powered devices.

Analog actually breaks little new technological ground with the gyro; researchers have long said such devices were the next logical step after accelerometers, and in fact MEMS gyros are sold now by Silicon Sensing Systems Ltd. and a few others. Analog's real advance is the dramatically lower cost.

"What's the big step is that Analog will bring the cost way down," said Jonathan Bernstein, vice president of technology at Corning IntelliSense. He gave the example of Honeywell, which already has MEMS gyros for military applications. "Those do perform much better than Analog," he said, "but you're certainly not going to get them for $15."

Most gyros today exist in at least two separate parts: the gyro to make positional measurements and the electrical sensor to interpret that data. They also have a central, nonsilicon mass. The ADXRS combines the two parts onto one chip without the central mass. Its packaging also does not need the typical vacuum-tight seal, another advance that lets Analog shave a few dollars off the manufacturing cost.

"They really try to beat you up on price," said Paul Turner, a research analyst at the Venture Development Corp. who follows Analog. "Even a few dollars' difference in cost makes a very big difference."

The most immediate market opportunity will be automotive sensors to activate airbags in the event of a rollover or when a car swerves out of control. Kevin Prouty, an automotive technology analyst at AMR Research, said the market for MEMS gyros could eventually reach several hundred million dollars or more, but he expected growth to be slow. He likened the technology to automotive air conditioning: considered a costly luxury when it first arrived, but now a standard feature in almost every vehicle made.

"You'll see this filter down to less expensive cars--that's where the big change will be," Prouty said.

The other potential market for the MEMS gyro: telematics, the science of determining position. While telematics is dominated today by Global Positioning System technology, cheap gyros could be used where GPS systems typically fail: in tunnels, beneath overpasses, through dense city neighborhoods or in dead spots along the GPS satellite network.

Because Analog's gyro gives a constant read on position and motion, Prouty said, "the computer should be able to calculate where you are relative to your starting point. Some system work does have to be done...but we're not talking about five years out. I don't see any major stumbling blocks."

Fibersense Technology Corp. in Canton, Mass., already uses the Analog sensor and GPS technology in an improved navigation system for urban bus lines. Fibersense is testing the product on bus lines in New York, Chicago and other major cities.

And new applications of cost-effective telematics would not be confined to the auto industry. For example, expensive gyros are used now for guided missiles. With Analog's cheaper version, it might be economically feasible to make guided artillery shells fired from tanks or battleships.

Analog and others also expect the gyros might find their way into robotics, toys, consumer electronics and other markets.

"The low cost will create new applications we haven't even thought of yet," said Bernstein, from Intellisense.