A critical factor when designing printed circuit boards is heat dissipation. If a PCB is not designed with proper heat dissipation techniques, it can cause components to overheat, leading to costly damage and even system failure.
Because complex PCBs generate more heat than their simpler counterparts, electronics companies and PCB designers must understand the different methods for dissipating excess heat to ensure their PCBs and products remain reliable.
Check out our guide to the best heat dissipation PCB design tips and learn how to avoid the pitfalls of excessive PCB heat build-up — and its costly consequences.
Adding Heat Sinks or Cooling Fans
Heat sinks are devices that absorb and dissipate heat away from PCBs and other components. They are made from aluminum or copper and are a passive cooling component, meaning they have no moving parts and rely solely on the natural conduction process to dissipate heat.
By augmenting the surface area and using thermally conductive materials such as copper or aluminum, these devices act as a buffer that helps maintain component temperature. They also allow the system to run longer since the lightweight, low-cost mechanisms don’t degrade performance over time.
Cooling fans, on the other hand, are active cooling components that actively draw hot air away from a unit while replacing it with cooler air. This replacement with cooling air helps to reduce the temperature of PCBs and other components significantly. While they can create a higher risk of electromagnetic interference issues, partnering with a PCB manufacturer that understands EMI shielding can help avoid any potential problems.
Choose the Right PCB Materials
Often, PCB overheating is a result of poor material selection. To minimize thermal conductivity losses, designers should use PCB materials with low thermal resistance and high thermal conductivity.
Copper is one of the best choices, as it’s a highly-effective conductor of heat; however, other metals, such as aluminum, also provide excellent heat dissipation and come at a lower manufacturing cost.
Additionally, PCBs with embedded heat-spreading layers composed of thermally conductive materials (glass polymers and copper foils) are an excellent solution for quickly dissipating considerable amounts of heat in high-performance systems.
Most importantly, partner with a reputable PCB manufacturer sourcing high-quality materials from trusted suppliers. Taking this crucial action will help ensure the PCBs are produced with superior thermal properties and that all components perform as expected.
Use Wider Traces
Metal traces are a core item of any PCB as they help transport electricity from one point to another. However, as current passes through the traces, they generate resistance and heat up. Smaller traces, while beneficial for PCB footprint size, are more vulnerable to heat build-up and aren’t ideal in PCBs producing high volumes of power.
By increasing the width of PCB traces, designers can reduce resistance and improve current flow, which helps dissipate heat more efficiently. For example, a trace with a wide cross-sectional area (1.5mm) can carry much higher currents than a trace with commonly used measurements ranging from .1mm to .15mm, allowing for better heat dissipation.
Additionally, as part of the trace width conversation, the topic of trace spacing will need addressing. Traces spaced closer together can cause excess heat build-up and are more prone to creating a short circuit. Therefore, PCB designers should design their component layout with sufficient trace spacing to avoid such issues. This step could mean using larger board designs and more expensive components, but ensuring the board runs cool and all parts stay reliable is well worth the increased manufacturing costs.
Thermal Via Arrays
Thermal via arrays are a type of thermal management design utilizing multiple vias to spread and dissipate heat. Created as through holes, thermal via arrays are laid out in a specific pattern and then filled with thermally conductive paste. This feature allows for a more efficient heat transfer over the surface of the PCB, lowering temperatures across the board.
In order to function correctly, the placement of thermal via arrays in close proximity to each other on the PCB surface is essential. The minimal distance between through holes facilitates the transfer of heat more efficiently from component areas of high thermal density to those with more airflow.
Using this type of thermal dissipation management design also helps reduce a PCBs susceptibility to temperature-related issues exacerbated by external environmental factors. Also, combining heat sinks or cooling fans with wider thermal via arrays is a great way to achieve additional heat dissipation when dealing with more extreme temperatures.
Plan Your PCB Layout Properly
Knowing the components and materials most beneficial to reducing the risk of heat build-up is only half the battle. Proper PCB layout design is equally important. Designers should carefully consider the positioning and orientation of components, as well as pay attention to airflow when working on a board.
For example, placing power components (CPUs and GPUs) in the center of the board ensures optimal heat dissipation, as opposed to arranging them in a corner where airflow is more restricted.
Additionally, components should be spaced out as far apart from each other as possible, and any heat-sensitive components (e.g., capacitors) require positioning further away from the center of the board to reduce their exposure to high temperatures.
Finally, PCB design should happen from the ground up with thermal management in mind — a process best completed by reputable PCB manufacturers through staggered layer stack-ups and optimized copper fill for wider trace spacing.
Don’t Allow Your PCB to Overheat
Printed circuit boards designed without proper thermal dissipation management can lead to component failure due to overheating. Although numerous design techniques are available to engineers looking to prevent thermal build-up, proper material selection and circuit layout planning remain the two most effective ways of avoiding this issue.
By taking the time to communicate your specific thermal requirements with your PCB manufacturer and carefully selecting components for their heat-dissipating properties, electronics enterprises can ensure that their board is safe from the dangers of thermal runaway.
Learn more about the common questions of PCB design to guarantee the best results for your current or upcoming PCB project.