LSM330DL Datasheet, PDF (17/54 Pages) STMicroelectronics – Linear sensor module 3D accelerometer sensor and 3D gyroscope sensor

LSM330DL
Module specifications
2.6
2.6.1
2.6.2
Terminology
Sensitivity
Linear acceleration sensitivity can be determined by applying 1 g acceleration to the device.
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 (point to the sky) and then 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 also very little over time. The sensitivity tolerance
describes the range of sensitivities of a large population of sensors.
Angular rate sensitivity describes the angular rate gain of the sensor and can be determined
by applying a defined angular velocity to it. This value changes very little over temperature
and also very little over time.
Zero level
Linear acceleration zero-g level offset (TyOff) 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 will measure 0 g on the X-axis and 0 g on the Y-axis whereas the Z-axis
will measure 1 g. The output is ideally in the middle of the dynamic range of the sensor
(content of OUT registers 00h, data expressed as 2’s complement number). A deviation
from the ideal value in this case is called zero-g 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 change vs. temperature” (refer toTable 3).
The zero-g level tolerance (TyOff) describes the standard deviation of the range of zero-g
levels of a population of sensors.
The angular rate zero-rate level describes the actual output value if there is no angular rate
present. Zero-rate level of precise MEMS sensors is, to some extent, a result of stress to the
sensor and therefore the zero-rate level can slightly change after mounting the sensor onto
a printed circuit board or after exposing it to extensive mechanical stress. This value
changes very little over temperature and also very little over time.
Doc ID 022018 Rev 1
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