TPS7H2201-SP: Power used for thermal resistance calculation

Hi Erick,

Our thermal models are generated under maximum power dissipation conditions allowed by Recommended Operating Condition ratings.

Please keep in mind that while the Thermal Metrics in the datasheet are excellent as a standardized comparison between packages and can be used for general approximation of thermals, their usefulness is limited if accurate calculation is needed. Thermal modeling can be complex and is highly dependent on the PCB design and layout, which likely differs from the layout of the standardized test board that is used to provide the Thermal Metrics.

Let me know if more clarification is needed.

Thanks,
Elizabeth

Thanks Elizabeth. So, if I want to calculate power (P=I^2*R), and in this particular case for recommended operating conditions I_max = 6A, what should I use for R? Is it 45mOhms, 87mOhms, or something else? Thanks for your help!

Hi Erick,

May I ask what you're trying to achieve with this calculation so I can better help you?

A power dissipation calculation would use R_ON, but that spec changes based on operating condition and temperature.

Thanks,
Elizabeth

Hi Elizabeth,

I am trying to determine what the estimated delta T would be between junction-case (top) and junction to case (bottom). If I have the thermal resistance from the datasheet, I can find out that information using the power from the device. So, depending on how the testing was conducted when determining the thermal resistance values I would know what the estimated R_ON value is. Can you tell what operating condition and temperature was used for determining the thermal metrics? 

Hi Erick,

Regarding R_ON, the worst case for power dissipation would be with the highest R_ON from the datasheet spec.

Thanks,

Elizabeth