SLUSDV7B October 2019 – March 2021 UCC23313-Q1
Refer to the PDF data sheet for device specific package drawings
Use Equation 14 to estimate the junction temperature (TJ) of UCC23313-Q1.
Using the junction-to-top characterization parameter (ΨJT) instead of the junction-to-case thermal resistance (RθJC) can greatly improve the accuracy of the junction temperature estimation. The majority of the thermal energy of most ICs is released into the PCB through the package leads, whereas only a small percentage of the total energy is released through the top of the case (where thermocouple measurements are usually conducted). The RθJC resistance can only be used effectively when most of the thermal energy is released through the case, such as with metal packages or when a heat sink is applied to an IC package. In all other cases, use of RθJC will inaccurately estimate the true junction temperature. The ΨJT parameter is experimentally derived by assuming that the dominant energy leaving through the top of the IC will be similar in both the testing environment and the application environment. As long as the recommended layout guidelines are observed, junction temperature estimations can be made accurately to within a few degrees Celsius.