STEVAL-IFS002V2 STMicroelectronics, STEVAL-IFS002V2 Datasheet - Page 18

• Manufacturer Part Number: STEVAL-IFS002V2
• Description: BOARD EVAL BASED ON LIS3LV02DL
• Manufacturer: STMicroelectronics
• Series: MEMSr

Specifications of STEVAL-IFS002V2

• Sensor Type: Accelerometer, 3 Axis
• Sensing Range: ±2g, 8g
• Interface: Analog and Digital
• Embedded: No
• Utilized Ic / Part: LIS302ALB, LIS302DL
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Voltage - Supply: -
• Sensitivity: -
• Other names: 497-8261

Mechanical and electrical specifications
2.5
2.5.1
2.5.2
2.5.3
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Terminology
Sensitivity
Sensitivity describes the gain of the sensor and can be determined e.g. by applying 1g
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 (point to the sky) and noting the output value again. By doing so,
±1g 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.
Zero-g level
Zero-g level Offset (Off) describes the deviation of an actual output signal from the ideal
output signal if there is no acceleration present. A sensor in a steady state on a horizontal
surface will measure 0g in X axis and 0g in Y axis whereas the Z axis will measure 1g. The
output is ideally in the middle of the dynamic range of the sensor (content of OUT registers
00h, 00h with 16 bit representation, data expressed as 2’s complement number). A deviation
from ideal value in this case is called Zero-g offset. Offset is to some extent a result of stress
to a precise 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”. The Zero-g level
of an individual sensor is stable over lifetime. The Zero-g level tolerance describes the range
of Zero-g levels of a population of sensors.
Self test
Self Test allows to test the mechanical and electric part of the sensor, allowing the seismic
mass to be moved by means of an electrostatic test-force. The Self Test function is off when
the self-test bit of CTRL_REG1 (control register 1) is programmed to ‘0‘. When the self-test
bit of CTRL_REG1 is programmed to ‘1‘ an actuation force is applied to the sensor,
simulating a definite input acceleration. In this case the sensor outputs will exhibit a change
in their DC levels which is related to the selected full scale and depending on the Supply
Voltage through the device sensitivity. When Self Test is activated, the device output level is
given by the algebraic sum of the signals produced by the acceleration acting on the sensor
and by the electrostatic test-force. If the output signals change within the amplitude
specified inside
interface chip are within the defined specification.
Table 3
or
4
then the sensor is working properly and the parameters of the
LIS3LV02DL