Webinar: Understanding Datasheet Thermal Parameters and IC Junction Temperatures

Automotive systems of the future will demand higher power and integrate more electronics, making thermal management a big area of concern. Unfortunately, it can be quite confusing trying to understand how a datasheet’s thermal parameters translate to your real design - when should you use theta instead of psi, for example, and how to convert PCB temperatures to what’s going on inside the IC.
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[@remy-]

After 24:10 the via is bridging heat to the bottom layer. In his book "PCB design guide and trace currents and temperatures - D Brooks", the author notices that the via is not bridging the temperature, but in fact being cooled by the large plane. He also mentions that the biggest heat transfer is in X-Y plane and also vertical. Would like to have your opinion.

[@monolithicpowersystemsmps534]

The biggest heat transfer to the environment is in the X-Y plane on the Top-Layer (1st. layer). FR4 Epoxy has poor thermal heat conductivity compared to copper. On a 4-layer, the second layer (inner) has a small distance, prepreg from TOP to the 2nd. Therefore, the heat transfer from TOP to this second. The layer is not so bad. The 2nd layer should be complete GND and spread the heat horizontally within the PCB. Layer 3 and BOT have a more considerable distance to the TOP layer and, therefore, more thermal isolating epoxy distance to TOP.
Thermal GND via are most suitable for transferring heat from TOP to the 2nd and BOT layer; the BOT layer can also radiate heat to the environment. Thermal via in the switching node are not recommended; these vertical via would radiate EMC. Thermal via in the Vin node close to the Vin pins also radiate EMC, but not so much as in the switching node.
The power pins (GND, Vin, SW) of a DC/DC converter can transfer the best heat from the junction to the PCB and use them as a heatsink; these pins are internally connected to the MOSFETs. The analog and digital pins (EN, PG, ....) can not transfer much heat from the junction.
Use the PCB copper as heatsink; GND is the best heatsink; SW-node is forbidden because of EMC and Vin as small polygon, not too large, a long Vin trace (without LC filter close to the pins) can oscillate at high frequency. The best thermal and EMC can be achieved with filled via under the pads or Micro via technology, but not all designs can use that PCB technology.

[@fabiovk]

please, can you provide me the PDF file? thanks.

[@monolithicpowersystemsmps534]

The PDF of the presentation can be found at: www.monolithicpower.com/en/support/videos/webinar-on-demand-understanding-datasheet-thermal-parameters-and-ic-junction-temperature.html