Thermal resistance measurement protocols

Thermal data supplied by manufacturers and used as a benchmark in a comparison of the thermal performance of different packages must be treated with caution, as the results are specific to the measurement environment of the supplier. For this reason, calculations of expected component thermal performance based on these data can be erroneous. This paper is an analysis of the discrepancies observed in thermal test results owing to small changes in the exact implementation of the measurements and in the calibration of the device temperature-sensitive parameter (diode V_f). It concludes with recommendations for ensuring more accurate and reproducible thermal resistance measurements.