Don’t forget about thermals when levelling up

At some point in your design journey, you will take the leap from designing products around microcontrollers to designing products or projects around microprocessors.

When you are working with microcontrollers, there is no need to think about thermals or having a thermal budget. The controllers are pretty power efficient as a result, very little heat is generated. But when you move on to design boards for microprocessors then thermals absolutely need to be considered.

Usually the hottest component in such designs is the processor itself.

Other components such as the ethernet chip, memories also generate a lot of heat. And the thing about heat is that it spreads. It heats up other components in the design, potentially changing their characteristics.

Capacitance and resistance are affected by these passive components.

Other than these there are power suppliers that are major heat sources. Especially linear regulators. Be mindful if you are using these regulators with large voltage differences.

Needless to say you need heat sinks or other ways like forced convection to displace the heat or a combination of the two.

You also need to study how to size the heat sink and learn about terms and their symbols for various temperature such as junction temperature, Ta - Air temperature. Th - Temperature of the heat spreader, etc. Others terms for thermal resistance between interfaces such as junction to heat spreader, and resistance of heat spreader to air, etc.

Don’t forget to account for heat in your next big project.