MEMS gyro/accelerometer combo chip debuts
R Colin Johnson
11/9/2010 7:36 AM EST
KYOTO, Japan—Micro-electro-mechanical systems (MEMS) vendor Invensense Inc. Tuesday (Nov. 9) introduced the world's first integrated MEMS to include both a gyroscope and accelerometer on a single CMOS die.
When used with a magnetometer (compass), the MPU-6000 forms a complete inertial measurement unit (IMU), according to Invensense (Sunnyvale, Calif.) . An integral motion processor core on the chip includes algorithms to fuse the outputs from the accelerometer, gyro and magnetometer to provide nine-degree-of-freedom functionality for applications including smart phones, touchscreen tablets, 3-D TV remote controls, gaming consoles, digital still- and video-cameras.
"What we bring to the market is a motion processor that is a complete nine-degree-of-freedom solution—bundling together a three-axis accelerometer and a three-axis gyroscope with on-chip algorithms for sensor fusion for a three-axis compass [magnetometer]," said Invensense Founder, Chairman and CEO Steven Nasiri. "We understand the limitations of these low-cost sensors and how to combine their outputs to get the best results, which is a technology on its own."
The stakes are huge, according Nasiri, who claimed that over 1 billion combined accelerometer and gyroscope units will be sold next year for applications such as gaming controllers, mobile phones, remote controls, appliances, health and sports monitors, toys, automotive, personal navigation and digital still and video cameras. That figure is expected to rise to more than 1.4 billion by 2013, according to Nasiri.
According to analysts, Invensense worked with Apple Inc. during the development of its own integrated motion processing capabilities for the iPhone 4, but lost the contract to STMicroelectronics NV over concerns that a small company like Invensense—with projected sales of about $80 million in 2010—could not meet demand. Invensense claims that it has included in the MPU-6000 all the algorithms for motion processing that Apple's iPhone 4 has, plus many more capabilities that will not be in Apple phones until future upgrades—including image stabilization for both still and video cameras. Invensense also claims it has filled in the gaps in its supply chain that now enable it to meet worldwide demand from even the largest vendors.
Invensense claims that over a billion MEMS gyros will be sold in 2011, rising to over 1.4 billion by 2013.
"We have transferred our proprietary process to TSMC eight-inch wafers, and are bringing other foundries on-board in order to meet the high-volume requirements of any customer," said Nasiri. "We are also the only true CMOS MEMS chip maker that uses the same process for our accelerometer and our gyroscope."
Besides the algorithms to detect orientation, inclination and motion that are built-into the iPhone 4 for its user interface, augmented reality and handheld gaming, the MPU-6000 also taps Invensense's original core-business expertise in image stabilization for still- and video-cameras plus adds sensor-fusion algorithms for "touchless" gestures and dead reckoning in both automotive- and pedestrian-navigation tasks.
According to Invensense, consumer-device manufacturers who decide to roll-their-own motion processing algorithms to perform MEMS sensor fusion will have to expend as much as 10 percent of their application processor's cycles performing them, plus will incur a year or more in software development efforts just to match Apple's iPhone. Choosing the MPU-6000, on the other hand, will give smartphones a leg-up on Apple, Invensense claims.
Invensense's proprietary fabrication process bonds the MEMS chip element to the ASIC in a stacked pair that seals the MEMS element against environmental contamination.
The 4-by-4-by 0.9 millimeter MPU-6000 has the same pin-out as Invensense's current three-axis gyro, automatically calibrates the gyro and compass bias, plus lays claim to the lowest noise (.005 degrees/second) and the highest resonant frequency of any consumer-grade gyro, according to Invensense.
Library-level software compatibility is provided for Android, Linux and Win7 operating systems today with MeeGo and Win7Phone libraries planned for 2011.
Earlier this year Invensense announced its intension to make an initial public offering , but has shelved those plans indefinitely until the investment environment improves.