I am evaluating the thermal performance of the PBSS5540Z BJT (bipolar junction transistor) and am measuring the case temperature using a Therma-Bridge (manufactured by IMS) to guarantee thermal conductivity between a J-type thermocouple and the PBSS5540Z collector case (the Therma-Bridge also guarantees electrical isolation). I need to accurately calculate the junction temperature of this part. Page 4 of 10 of the attached datasheet shows the junction to ambient thermal resistance (Rth_JA). To calculate an accurate junction temperature, I need to know the junction to case thermal resistance (Rth_JC), since case temperature was measured and Rth_JA = Rth_JC + Rth_CA (thermal resistance from case ambient).
What is the thermal resistance from junction to case (Rth_JC) on this part? I have already contacted Nexperia 2 weeks ago and posted a similar technical support ticket on their website, but no one has responded yet and I need this information ASAP.