Offset issue with MEMs Sesnor LIS2DW12TR

[SeniorGuru]

Dear all,

We are using the LIS2DW12TR on a custom PCB and have observed significant offset errors on the Z-axis, reaching up to ±20% of full scale.

The sensitivity appears to be correct; however, instead of measuring the expected values of +1 g and −1 g, we obtain readings such as +1.17 g and −0.83 g. This suggests a substantial offset while the sensitivity remains largely unaffected.

The X- and Y-axes do not exhibit this behavior and remain within specification.

The most unusual aspect is, that the offset is not stable. It changes very slowly over time, typically over a period of several days, without any intentional modification of the hardware or software configuration.

Has anyone experienced similar behavior with the LIS2DW12TR or identified possible causes such as PCB stress, assembly process effects, flux contamination, humidity, temperature exposure, or aging effects?

Any recommendations for further investigation would be greatly appreciated.

Best regards,
Reto

 

[Federica Bossi]

Hi ​@SeniorGuru ,

Based on the symptoms, this behavior is more consistent with a mechanical or assembly-related offset issue than with a sensitivity problem. Since the sensitivity appears correct and the behavior is mainly on the Z axis, the most likely causes are package/PCB stress or solder-joint stress. A slowly changing offset over several days can also be related to stress relaxation, humidity or/and temperature history.

This is not typically expected from the sensor itself if it is correctly mounted and operated within specification.

What you could check:

• Measure the sensor before soldering and compare with the final assembly.
• Verify whether the offset changes with screws or board bending.
• Correlate the offset drift with temperature and humidity.
• Review assembly and reflow conditions, including PCB warpage and solder paste distribution.
• Run the self-test to confirm the sensor is good.