Terms you’re looking for in your datasheet

Generally, these datasheets indicate: power dissipation (W), the maximum junction temperature (commonly °C) and a junction-to-case thermal resistance (generally °C/W) in the Thermal section.

The actual math part: calculate max case temperature

In order to calculate maximum case temperature, first multiply the amount of heat the device dissipates by the junction-to-case thermal resistance to get the temperature rise from the junction to case. Then subtract this temperature rise from the maximum junction temperature to get the maximum case temperature.

Tjunction-max – (Ɵjunction-to-case*Pdissipated) = Tcase-max

In some cases, device datasheets may contain additional complexity. Thermoelectric Coolers (TECs) or Thermoelectric Devices (TEDs) can be doubling confusing since there is a hot side and a cold side, and the control of both sides is critical to function.

Multiple devices or system heat loads

If you have multiple devices or an existing system that you want to cool together, you may want to test your thermal load instead of calculating, especially for retrofit situations.

Additional support

If you need assistance, please don’t hesitate to contact Eaton design engineers. We've had extensive experience in reading these types of datasheets and help you design the right solution for you.