Micropower, 3-Axis, ±200 Digital Output, MEMS Accelerometer

The ADXL371 is an ultra low power, 3-axis, ±200 g microelectromechanical system (MEMS) accelerometer that consumes 28 μA at a 2560 Hz output data rate (ODR). The ADXL371 does not power cycle its front end to achieve its low power operation and therefore does not run the risk of aliasing the output of the sensor.

In addition to its ultra low power consumption, the ADXL371 enables impact detection while providing system level power reduction. The device includes a deep multimode output first in, first out (FIFO), several activity detection modes, and a method for capturing only the peak acceleration of overthreshold events.

Two additional lower power modes with interrupt driven, wake-up features are available for monitoring motion during periods of inactivity. In wake-up mode, acceleration data can be averaged to obtain a low enough output noise to trigger on low g thresholds. In instant on mode, the ADXL371 consumes 1.7 μA while continuously monitoring the environment for impacts. When an impact event that exceeds the internally set threshold is detected, the device switches to normal operating mode fast enough to record the event.

High g applications tend to experience acceleration content over a wide range of frequencies. The ADXL371 includes a four-pole, low-pass antialiasing filter to attenuate out of band signals that are common in high g applications. The ADXL371 also incorporates a high-pass filter to eliminate initial and slow changing errors, such as ambient temperature drift.

The ADXL371 provides 12-bit output data at a 100 mg/LSB scale factor. The user can access configuration and data registers via the serial peripheral interface (SPI) or I2C protocol. The ADXL371 operates over a wide supply voltage range and is available in a 3 mm × 3.25 mm × 1.06 mm package.

APPLICATIONS

* Impact and shock detection

* Asset health assessment

* Portable Internet of Things (IoT) edge nodes

* Concussion and head trauma detection

* ±200 g measurement range

* 160 Hz to 2560 Hz user selectable bandwidth with four-pole antialiasing filter

* Selectable oversampling ratio

* Adjustable high-pass filter

* Ultra low power

* Power can be derived from a coin cell battery

* 28 µA at 2560 Hz ODR, 3.3 V supply

* Low power, wake-up mode for low g activity detection

* 1.7 μA instant on mode with adjustable threshold

* <0.1 μA standby mode

* Built in features for system level power savings

* Deep embedded FIFO to minimize host processor load

* Autonomous interrupt processing without processor intervention