Hysteresis Phenomenon
Non-repeatability of sensor output measurements during and after a complete temperature sweep is caused by the different rates of heating and cooling of the internal components. Precision transducers suffer from transient thermal hysteresis when the sensor output does not return to its original value after being heated and then cooled back to the starting temperature. This discrepancy is caused by the delayed temperature distribution across the different materials in the package.
This phenomenon is particularly problematic in applications like meteorological balloons or automotive exhaust sensors where the temperature sweeps are rapid and continuous.
Stress Interaction
Thermal expansion mismatches between the silicon sensor die, the substrate, and the protective casing generate transient mechanical stresses during temperature changes. These stresses distort the sensor element, creating temporary electrical shifts that only decay after the entire assembly reaches thermal equilibrium.
Compensation Limit
Since the error depends on both the current temperature and the rate of temperature change, standard static correction algorithms cannot easily eliminate this effect. To minimize this error, system designers use advanced state-space models that track the thermal history of the sensor to compute a dynamic correction factor.
Characterization Method
Quantifying this effect requires subjecting the sensor to a slow, controlled temperature ramp up and down in an environmental chamber while recording the output drift. This testing establishes the hysteresis envelope of the sensor, which must remain within the specified tolerance limits of the application.
