ADXL371 MEMS Accelerometer

ADI's ADXL371 is an ultralow 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 ultralow 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 over-threshold 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 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.

The EVAL-ADXL371Z is a simple evaluation board that allows quick evaluation of the performance of the ADXL371 ultralow power, 3-axis, digital output MEMS accelerometer. The EVAL-ADXL371Z is ideal for the evaluation of the ADXL371 in an existing system because the stiffness and the small size of the evaluation board minimize the effect of the board on both the system and acceleration measurements.

Features

• ±200 g measurement range
• 160 Hz to 2560 Hz user-selectable bandwidth with four-pole antialiasing filter
• Selectable oversampling ratio
• Adjustable high-pass filter
• Ultralow 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
• Ultralow power event monitoring detects impacts and wakes up fast enough to capture the transient events
• Adjustable, low g threshold activity and inactivity detection
• Wide operating voltage range: 2.5 V to 3.5 V
• Acceleration sample synchronization via external trigger
• SPI digital and I²C interface formats supported
• 12-bit output at 100 mg/LSB scale factor
• Wide temperature range: -40°C to +105°C
• Small, thin, 3 mm × 3.25 mm × 1.06 mm package