The Role of Thermal Vias in PCBs

Thermal Vias in PCBs

As electronic devices evolve and operate to ever-increasing operational levels, they create a lot of heat. This unavoidable energy dissipation can slow down circuit speeds, cause thermal fractures, or even cause outright component failure. To minimize this, PCB designs use a variety of techniques, including vias that are specifically designed for dissipating heat.

The copper layer in a circuit board provides an excellent surface for heat transport and dissipation. However, it also has high electrical resistance. This combination of factors can cause “hot spots” to form around active components that generate a large amount of heat. These hot spots can then affect performance of the entire board. The best way to mitigate this problem is by incorporating thermal vias into your pcb design.

Thermal vias are holes extending through the multiple layers of your circuit board that are filled with conductive epoxy and plated over. They are typically placed directly under the components that generate the most heat, and are dedicated to thermal transfer. By providing a low-resistance path for the heat to flow, thermal vias can dissipate that heat more effectively than other means.

The Role of Thermal Vias in PCBs

When used properly, thermal vias can significantly reduce the temperature of your components and improve your overall board performance. By leveraging the high thermal conductivity of copper in your inner layers, they can efficiently transport that heat away from the components to dissipate into the surrounding environment.

While the benefits of thermal vias are obvious, it is important to remember that they need to be properly placed to maximize their impact. The most important factor in their effectiveness is the temperature difference between a component’s pad and the surrounding copper surface. This temperature difference is the primary reason why thermal vias should be positioned directly under the hot pads of your components, and not at the edge of the board where their effect would be less effective.

Fortunately, your ECAD software has tools that can help you plan the geometry and placement of thermal vias to manage your component’s temperature in this way. In addition to standard via layout tools, the best ECAD platforms have stackup design features that allow you to define internal copper layers that will help manage heat throughout your board.

Using these tools, you can plan a consistent and robust thermal management strategy. Then, when you’re ready to route your boards, you can use automated routing tools like fanout routers to position the vias where they will have the most impact. This will ensure your designs always comply with IPC-2152 standards for thermal management, and that your boards will perform at their peak. In addition, this will help you avoid the additional costs and timeline delays associated with adding unnecessary vias. By planning your thermal management with CAD tools, you can be confident that your final product will meet the quality and performance requirements of your customers.

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