JAJSNY9B September 2022 – February 2023 TPSM365R3 , TPSM365R6
PRODUCTION DATA
As with any power conversion module, the TPSM365Rx dissipates internal power while operating. The effect of this power dissipation is to raise the internal temperature of the power module above ambient. The internal die and inductor temperature (TJ) is a function of the ambient temperature, the power loss, and the effective thermal resistance, RθJA, of the module and PCB combination. The maximum junction temperature for the TPSM365Rx must be limited to 125°C. This establishes a limit on the maximum module power dissipation and, therefore, the load current. Equation 12 shows the relationships between the important parameters. It is easy to see that larger ambient temperatures (TA) and larger values of RθJA reduce the maximum available output current. The power module efficiency can be estimated by using the curves provided in this data sheet. If the desired operating conditions cannot be found in one of the curves, interpolation can be used to estimate the efficiency. Alternatively, the EVM can be adjusted to match the desired application requirements and the efficiency can be measured directly. The correct value of RθJA is more difficult to estimate. As stated in the Semiconductor and IC Package Thermal Metrics application report the values given in Thermal Information section are not valid for design purposes and must not be used to estimate the thermal performance of the application. The values reported in that table were measured under a specific set of conditions that are rarely obtained in an actual application.
where
The effective RθJA is a critical parameter and depends on many factors such as the following:
As a reference, the effective RθJA on the EVM for typical 24-V VIN 5-V VOUT full-load condition is around 30 °C/W. Use the following resources as guides to optimal thermal PCB design and estimating RθJA for a given application environment: