LIS2DUXS12 datasheet(12/104 Pages) STMICROELECTRONICS

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Terminology and functionality

3.1

Terminology

3.1.1

Sensitivity

Sensitivity describes the gain of the sensor and can be determined by applying 1 g acceleration to it. As the

sensor can measure DC accelerations this can be done easily by pointing the axis of interest towards the center

of the Earth, noting the output value, rotating the sensor by 180 degrees (pointing to the sky) and noting the

output value again. By doing so, ±1 g acceleration is applied to the sensor. Subtracting the larger output value

from the smaller one, and dividing the result by 2, leads to the actual sensitivity of the sensor. This value changes

very little over temperature and time. The sensitivity tolerance describes the range of sensitivities of a large

population of sensors.

3.1.2

Zero-g level offset

Zero-g level offset describes the deviation of an actual output signal from the ideal output signal if no acceleration

is present. A sensor in a steady state on a horizontal surface measures 0 g on the X-axis and 0 g on the Y-axis

whereas the Z-axis measures 1 g. The output is ideally in the middle of the dynamic range of the sensor (content

of OUT registers 00h, data expressed as two’s complement number). A deviation from ideal value in this case is

called zero-g level offset. Offset is to some extent a result of stress to the MEMS sensor and therefore the offset

can slightly change after mounting the sensor onto a printed circuit board or exposing it to extensive mechanical

stress. Offset changes little over temperature, see “Zero-g level offset change vs. temperature”.

3.2

Functionality

3.2.1

Operating modes

The LIS2DUXS12 has 4 operating modes: high-performance, low-power, ultralow-power and one-shot mode.

In low-power mode, an aggressive anti-aliasing filter is active, but the overall current consumption remains

extraordinarily low (refer to Table 3).

3.2.2

One-shot modes

The device features two one-shot modes: one-shot triggered by the INT2 pin, and one-shot triggered by the

I²C/SPI/I3C digital interface.

3.2.3

Self-test

Self-test mode allows checking the sensor functionality without moving it, applying an actuation force to the

sensor and simulating a definite input acceleration.

LIS2DUXS12

Terminology and functionality

DS14035 - Rev 2

page 12/104

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