MSP430F437: MSP430f437

Hello Andrea,

Unfortunately, I could not find that information in the datasheet, and I'm not able to provide those characteristics. I suspect the junction-to-ambient thermal resistance (RθJA) isn't given because it's the most commonly reported thermal metric but often the most misused.

The thermal performance of a TI device can be compared to a device from another company. This is true when both companies use a standardized test to measure RθJA, such as that specified by JEDEC in the EIA/JESD51-x series of documents. Sometimes, however, JEDEC conditions are not followed and the excursions from the standards are not documented. These test variations can have a dramatic effect on the measured values of RθJA. Therefore, unless test conditions are reported with the RθJA value, they should be considered suspect.

RθJA is a variable function of not just the package, but of many other system level characteristics such as the design and layout of the printed circuit board (PCB) on which the part is mounted. In effect, the test board is a heat sink that is soldered to the leads of the device. Changing the design or configuration of the test board changes the efficiency of the heat sink and therefore the measured RθJA. In fact, in still-air JEDEC-defined RθJA measurements, almost 70%–95% of the power generated by the chip is dissipated from the test board, not from the surfaces of the package.

In the figure below, you can see that RθJA is affected by more than just the package itself.

In light of the fact that RθJA is not a characteristic of the package by itself but of the package, PCB, and other environmental factors, it is best used as a comparison of package thermal performance between different companies. You can read more about this in our Semiconductor and IC Package Thermal Metrics app note.

Regards,

James

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