The Price Curve between Accuracy Grades in One Product Family
Sensor accuracy price curves scale exponentially because higher tiers demand longer thermal chuck dwell times, lower silicon yields, and guard-banded calibration.
EEPROM Compensation
Correction Mechanism
Digital adjustment of sensor output through values stored in non-volatile memory enables the removal of systematic errors from the measurement signal. Applying eeprom compensation involves reading unique coefficients from the chip memory and using them to calculate a corrected value in real time. This method allows low cost sensors to achieve high accuracy.
Coefficient Calculation
Characterization of the sensor over its full operating range produces a set of data points that describe its error profile. These points are converted into mathematical coefficients that represent the inverse of the error curve and are then written into the memory during the final factory test. Because every sensor has slightly different characteristics, the values in the eeprom compensation table are unique to each individual unit.
Thermal Mitigation
Temperature effects represent one of the largest sources of error in most sensing elements, but they can be largely removed using these digital techniques. The eeprom compensation routine typically includes a temperature input that allows the processor to select the correct offset and gain adjustment for the current environment. This dynamic adjustment maintains the sensor within its specified tolerance even as the ambient conditions change rapidly during operation.
Verification Step
Quality control processes include a final measurement after the coefficients are programmed to ensure the correction is effective. A sensor that remains outside of its error band after the digital adjustment is discarded.