LIS33DE STMicroelectronics, LIS33DE Datasheet - Page 13

• Manufacturer Part Number: LIS33DE
• Description: Board Mount Accelerometers MEMS MOTION SENS 3 AXIS 2G/8G SDO NANO
• Manufacturer: STMicroelectronics

Specifications of LIS33DE

• Sensing Axis: Triple
• Acceleration: 2 g, 8 g
• Supply Voltage (max): 3.6 V
• Supply Voltage (min): 2.16 V
• Supply Current: 0.3 mA
• Maximum Operating Temperature: + 85 C
• Minimum Operating Temperature: - 40 C
• Digital Output - Bus Interface: I2C, SPI
• Sensitivity: 18 mg/digit, 72 mg/digit
• Package / Case: LGA-16
• Output Type: Digital
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

LIS33DE
2.5
2.5.1
2.5.2
2.5.3
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 (pointing 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 time. The Sensitivity tolerance describes
the range of sensitivities of a large population of sensors.
Zero-g level
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
measure 0g in X axis and 0g in Y axis whereas the Z axis measure 1g. 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 ideal value in this case is called
Zero-g offset. Offset is to some extent a result of stress to 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 tolerance (TyOff) describes the Standard
Deviation of the range of Zero-g levels of a population of sensors.
Self test
Self Test allows to check the sensor functionality without moving it. 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 exhibit a change in
their DC levels which are related to the selected full scale 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
working properly and the parameters of the interface chip are within the defined
specifications.
Doc ID 15596 Rev 1
Mechanical and electrical specifications
Table
3, then the sensor is
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