Micropower, 3-Axis, ±2 /±4 /±8 Digital Output MEMS Accelerometer

The ADXL362 is an ultralow power, 3-axis MEMS accelerometer that consumes less than 2 μA at a 100 Hz output data rate and 270 nA when in motion triggered wake-up mode. Unlike accelerometers that use power duty cycling to achieve low power consumption, the ADXL362 does not alias input signals by undersampling; it samples the full bandwidth of the sensor at all data rates.

The ADXL362 always provides 12-bit output resolution; 8-bit formatted data is also provided for more efficient single-byte transfers when a lower resolution is sufficient. Measurement ranges of ±2 g, ±4 g, and ±8 g are available, with a resolution of 1 mg/LSB on the ±2 g range. For applications where a noise level lower than the normal 550 μg/√Hz of the ADXL362 is desired, either of two lower noise modes (down to 175 μg/√Hz typical) can be selected at minimal increase in supply current.

In addition to its ultralow power consumption, the ADXL362 has many features to enable true system level power reduction. It includes a deep multimode output FIFO, a built-in micropower temperature sensor, and several activity detection modes including adjustable threshold sleep and wake-up operation that can run as low as 270 nA at a 6 Hz (approximate) measurement rate. A pin output is provided to directly control an external switch when activity is detected, if desired. In addition, the ADXL362 has provisions for external control of sampling time and/or an external clock.

The ADXL362 operates on a wide 1.6 V to 3.5 V supply range, and can interface, if necessary, to a host operating on a separate, lower supply voltage. The ADXL362 is available in a 3 mm × 3.25 mm × 1.06 mm package.

APPLICATIONS

* Hearing aids

* Home healthcare devices

* Motion enabled power save switches

* Wireless sensors

* Motion enabled metering devices

* Ultralow power

* Power can be derived from coin cell battery

* 1.8 μA at 100 Hz ODR, 2.0 V supply

* 3.0 μA at 400 Hz ODR, 2.0 V supply

* 270 nA motion activated wake-up mode

* 10 nA standby current

* High resolution: 1 mg/LSB

* Built-in features for system-level power savings:

* Adjustable threshold sleep/wake modes for motion activation

* Autonomous interrupt processing, without need for microcontroller intervention, to allow the rest of the system to be turned off completely

* Deep embedded FIFO minimizes host processor load

* Awake state output enables implementation of standalone, motion activated switch