Shown here is data in a smaller range to remove the largest nonlinearities at the extreme positive and negative temperature ranges. Between 0°C and above 1000°C that the error for non linearization can be between -4 to +7oC, while the MAX31856 is less than ±0.05oC due to the internal linearization. This data is typical data from a few devices. The MAX31856 datasheet specification for maximum linearization is ±0.25oC. Not linearizing may be okay over limited temperature ranges, but it is clear that linearization is needed for accurate wide-range thermocouple measurement.