Six-axis MEMS sets new size/power lowPORTLAND, Ore.—The latest six-axis MEMS combo chip combining a three-axis accelerometer and three-axis gyroscope from Invensense Inc. (Sunnyvale, Calif.) sets a new low in size and power.
"Our new MPU-6500 we reduced its size by 45 percent over our previous accelerometer-gyro chip, plus lowered its power consumption by nearly 60 percent versus our nearest competitor," said Daniel Goehl, Invensense vice president and co-founder.
In 2010 Invensense announced the world's first six-axis accelerometer/gyroscope combo chip—the MPU-6000—which measured 4-by-4 millimeters, but earlier this year Bosch Sensortec announced a six-axis combo chip that measured 3-by-4.5 millimeter (16 percent smaller than MPU-6000). Also last year, STMicroelectronics—supplier of accelerometers and gyroscopes for Apple's iPad and iPhone announced a six-axis combo chip but it measured 4-by-5 millimeter (25 percent bigger than MPU-6000). Invensense's latest six-axis combo chip now sets a new low, making it the undisputed smallest-size award winner by measuring just 3-by-3 millimeters.
Invensense also lays claim to the lowest power consumption, by virtue of eliminating the need for a three-volt power supply to its MEMS devices.
"Invensense is the only MEMS chip maker who has been able to get the power supply down to a single 1.8 volt supply," said Goehl. "That gives us the lowest power in the industry—just 6.1 milliWatts of power in full operating mode and just 18 microAmps when in low-power mode."
Invensense also claims to be the only MEMS maker to integrate a complete digital motion processor (DMP) on-chip—to handle the sensor fusion and auto-calibration tasks. By including its MotionTracking algorithms on-chip in the hardware DMP unit, there is no need to add a microcontroller or to run auto-calibration and motion processing algorithms on the application processor, as is required by MEMS chip makers that offer only motion-processing and sensor-fusion algoritms in software libraries. The latest incarnation of its DMP is fully compliant with the motion processing requirements for Google’s latest Android 4.1 Jelly Bean release.
Invensene also claims that by boosting the performance of its MEMS elements, which are wafer bonded to the ASIC holding the DMP and other CMOS circuitry using a proprietary process (see figure), it is targeting next-generation high-performance location-based services, such as pedestrian navigation and context-aware advertising.
Invensene's customer's do not allow it to publicize the use of its chip in their gaming controllers, tablets and smartphones, but teardowns have found Invensense's current generation MEMS chips in the Nintendo Wii, Sony PS3, Samsung Galaxy, the latest Google Nexus 7 tablet, and nearly every brand of smartphone besides Apple and Nokia.