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It shouldn’t come as a surprise that electronics that require more power to operate will generate more heat. Components like voltage regulators, microcontrollers, and power transistors are all known to heat up when the load current increases.

Electronic components are all built to operate within a finite temperature range. If the surrounding temperature exceeds the upper limit, the components can break down. Even if it doesn’t break, the excessive heat will negatively affect the component’s performance.

When electronic components are exposed to excessive heat over a prolonged period, their lifespan shortens. If you’re negligent in your utilization of PCB heat dissipation techniques, you’ll soon face the issues related to premature component failures.

What are 5 main PCB heat dissipation techniques?

Identifying thermal and high-current traces

To fabricate a thermally stable PCB, thermal effects must be studied during the designing phase itself. The first step in thermal design is to identify the hotspots. Thermal modeling or thermal simulation techniques are used to find hotspots. Also, current flow analysis must be done along with it, because high-current traces cause heat generation.

The proper geometrical arrangement of components and high-current traces enables even distribution of heat. High-current traces must be routed away from thermally sensitive components such as sensors and Op-amps.

  • Use wider traces for reduce heat

Copper traces that conduct high currents build up heat. Therefore, it is important to increase the width of the trace to maximize heat dissipation to the air. Doing so also reduces the thermal resistance of the trace and reduces heat spots.

  • PCB thermal vias design

You can turn a PCB into an onboard heat sink by incorporating thermal via arrays over copper-filled areas, as shown above. The idea behind doing so is to have heat flowing from components to the copper area and dissipating through the air from the vias. Usually, thermal via arrays are used for power management modules and components with thermal pads.

When implementing thermal via arrays, remember that it needs to have a reasonably large diameter, in the region of 0.1 mm, for the heat to be dissipated effectively. Also, ensure the vias are not thermal-relief pads but padded holes that are connected to the copper area at all sides. Increasing the number of thermal vias further helps with heat dissipation.

  • Proper material to help heat dissipation

There are materials other than epoxy resins that are better suited to dissipate disproportionate levels of heat such as polyimides or metal cores. If these materials are used, the decision has to be made upfront as these materials will have very different electrical characteristics, completely changing the structure of the design.

  • Pay attention to routing process

The more metal that is on the board, the more the heat can dissipate through it. At the same time, power components require short routes to keep their inductance low. To satisfy both needs, use wider traces and/or more copper weight. For ground nets, it is best to use solid metal planes whenever possible as long as you can maintain the short and direct routing requirements.

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