Date: 07/06/2012

3-axis digital MEMS accelerometer from Analog saves system-level power

Analog Devices, Inc has introduced a low power, 3-axis, digital MEMS accelerometer ADXL362. The device operates at 300 nA in motion sensing wake-up mode. In full measurement mode, the ADXL362 uses 2 µA at a 100 Hz data rate. This low power consumption allows the ADXL362 to be used in applications that require battery life expectancy of months or years, and where battery replacement can be impractical or dangerous to the equipment or operator.

The ADXL362 enables system-level power savings as the device can be used as part of an intelligent, continuously operational, motion-activated switch. Equipped with an Awake Status output pin, the motion sensor can instantly trigger a switch that turns on system functions, bypassing the processor, to further reduce system power.

"Designing for low power requires more than low current draw at the component level, it also means intelligently managing total system power by turning system functions on and off at precisely the correct time," said Bill Murphy, product line director, MEMS/Sensors group, Analog Devices. "The ADXL362 leads the industry in this respect, enabling applications ranging from healthcare to infrastructure monitoring, where battery life is absolutely critical."

The device integrates an enhanced, sample activity detection function that distinguishes between different kinds of motion. This eliminates false positives and prevents the sensor from turning the system on unnecessarily and costing additional battery life. The device embeds a deep internal FIFO memory block that allows system designers to record data and stream long data sets.

The ADXL362 is planned for implementation into the second generation of DARPA's Blast Gauge, which was developed at Rochester Institute of Technology and commercialized by BlackBox Biometrics to protect U.S. Armed Forces personnel.

"Using ADI's high-performance MEMS sensors, the Blast Gauge has proven to reliably detect concussive forces experienced by the men and women of our Armed Forces. The ADXL362 will significantly extend battery life in these sealed devices which utilize a non-rechargeable battery," said David Borkholder, chief technology officer of BlackBox Biometrics.

Features:
1. Ultra low current in all operating modes
2. 2 µA at 100 Hz in full measurement mode
3. 300 nA in wake-up mode
4. 10 nA in standby
5. Acceleration data with 12-bit resolution
6. 8 bit formatted data for efficient single-byte transfers
7. Measurement ranges of ±2 g, ±4 g, and ±8 g, with a resolution of 1 mg/LSB on the ±2 g range
8. Include two lower-noise modes that allow the user to roughly halve the noise at the expense of a few microamps (µA)

Product Sample availability Full production Price each per 1,000 Packaging
ADXL362 Now Aug-12 $3.97 3 × 3.25 × 1.06 mm 16-lead LGA