Parameter Definition
Sensor metrology specifies baseline output variation as a function of ambient temperature under zero input conditions. The thermal coefficient of offset quantifies zero-point shift per degree Celsius change, expressed in microvolts per degree or percentage of full scale output. This metric models baseline stability across rated operating temperature ranges for pressure and inertial sensors.
Operational boundaries restrict this parameter to specified linear operating bands, excluding phase change or thermal damage regimes.
Temperature Sensitivity
Differential thermal expansion across sensing elements and package substrates generates internal mechanical stress that shifts zero-point electrical outputs. Semiconductor strain gauges exhibit temperature-dependent piezoresistive coefficients that alter baseline resistance balances. Symmetrical sensor bridge designs reduce net thermal offset shifts by cancelling matching drift vectors across opposing bridge arms.
Uncompensated thermal offset shifts create zero errors that propagate through signal processing chains.
Trimming Compensation
Automated calibration systems measure zero-input output values at multiple temperature setpoints to compute individual device offset curves. On-chip digital register adjustments or thin-film resistor trimming balance sensor bridge outputs at reference temperatures. Multi-order polynomial compensation networks correct non-linear offset drift across wide operational ranges.
Compensation quality depends on temperature sensor proximity to active sensing elements.
Verification Limit
Environmental test chambers must stabilize at calibration temperatures before logging zero-input baseline output values. Thermal hysteresis effects produce different baseline offsets depending on whether temperature approaches from upper or lower extremes. Calibration standards mandate baseline stability verification across complete thermal cycles.
Test documentation lists maximum residual offset drift values across rated operating ranges.
