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7 Ways To Improve PCB Thermal Management & Reduce PCB Heat

Nowadays, electronic products are compact and lightweight due to effective PCB thermal management. On a printed circuit board (PCB), various components are assembled to perform different tasks, and in the process, they generate heat—especially when packed into a small space. If the heat becomes too much, it can affect the PCB’s performance, cause early component failure, or even lead to device failure. That’s why improving PCB thermal management is a crucial step during the PCB design process.

Because effective thermal management is essential for ensuring the longevity and reliability of your PCB. Here are seven critical techniques you can use to reduce PCB heat and enhance your PCB’s thermal management:

What Is PCB Thermal Management?

PCB Thermal Management

PCB thermal management refers to the methods used to control the heat produced by the components on the board. To effectively improve thermal management, there are several techniques you can use—such as adding heat sinks, thermal vias, or copper planes to efficiently spread and remove heat from specific areas of the PCB. The goal here is to keep all components running optimally, extending the lifespan and improving the performance of your electronic device. By focusing on proper thermal management, you’ll ensure your PCB performs reliably, even in the most compact designs.

Check Also: 5 Ways To Maximize Performance With PCB Cross-Hatching

Factors Affecting PCB Thermal Performance

The thermal performance of PCBs is a crucial quality factor in electronic packaging, especially in high-power applications where the temperature distribution within components is a key parameter for long-term reliability. Here are some of the main influencing factors:

Factors

1. Component Placement

2. PCB Material and Thickness

3. Copper Trace Width and Thickness

4. Thermal Vias

5. Use of Heat Sinks

6.Airflow and Ventilation

7. Power Density

8. Thermal Interface Materials (TIM)

9. Multilayer Design

10. Operating Environment

Ways To Improve PCB Thermal Performance

Here are various strategies to boost the thermal efficiency of PCBs. By applying these methods, engineers can substantially enhance the thermal management of PCBs, resulting in more dependable and effective electronic devices.

1. Optimize Component Placement

Strategic component placement on a PCB can dramatically influence the thermal performance of electronic devices. By carefully considering the layout of components, engineers can mitigate heat-related issues and ensure the longevity and reliability of the system. Here are some detailed strategies for optimizing component placement:

Component Placement
  • Position high-power components away from heat-sensitive devices to prevent thermal crosstalk and ensure that sensitive components operate within their specified temperature ranges.
  • Ensure there is adequate space for proper airflow around all components. This is crucial for maintaining a stable operating temperature, as it allows for the circulation of air and the dissipation of heat.
  • When planning the layout, consider the thermal interaction between nearby components. Components that generate heat should be placed in a way that does not adversely affect the temperature of surrounding parts, which could lead to performance degradation or failure.

2. Use Thermal Vias

Thermal vias serve as heat conduits, facilitating the transfer of heat from the top layers of the PCB to the bottom layers or directly to a heat sink. By strategically incorporating thermal vias into the design, engineers can effectively distribute heat across the PCB, thereby reducing hotspots and improving the overall thermal efficiency. Here are some detailed design guidelines for incorporating thermal vias:

Thermal Vias
  • Use multiple smaller vias instead of a few large ones. This approach increases the surface area for heat transfer, allowing for more efficient heat dissipation. Smaller vias can also be placed more densely, which can help in distributing heat more evenly across the PCB.
  • Arrange the vias in a grid pattern beneath heat-generating components. This configuration ensures that heat is transferred uniformly away from the components, reducing the risk of localized overheating. The grid pattern also provides a structured and organized method for heat management.
  • Whenever possible, fill the vias with thermally conductive material, such as copper or a specialized thermal paste. This step enhances the heat transfer capabilities of the vias, as these materials have high thermal conductivity and can quickly draw heat away from the components.

3. Enhance Copper Thickness

Enhancing the copper thickness in PCB layers is a straightforward yet effective method to improve thermal management. Thicker copper traces facilitate better heat distribution and quicker dissipation, which is useful for maintaining the performance and longevity of electronic components. Here’s a deeper look at how increasing copper thickness can benefit thermal efficiency:

  • Thicker copper traces, such as those with a 2oz or higher weight, offer lower thermal resistance compared to thinner traces. This reduction in resistance allows heat to flow more freely through the copper, which is an excellent conductor of heat.
  • The increased copper thickness can act as a heat spreader, helping to distribute heat over a larger area and reducing the concentration of heat in any single spot, thus preventing hotspots.
  • Thicker copper layers can also improve the overall mechanical strength of the PCB, which is beneficial for withstanding the stresses of manufacturing and the thermal expansion that can occur during operation.

4. Apply Heat Sinks and Thermal Pads

For high-power components, the installation of heat sinks and thermal pads is a critical strategy to significantly enhance heat dissipation. These components are designed to absorb heat and transfer it away from sensitive areas, thereby maintaining optimal operating temperatures. There are two types of heat sinks that can be considered for thermal management: passive and active heat sinks. When incorporating heat sinks into your design, consider the following factors:

Heat Sinks and Thermal Pads
  • Thermal Resistance: This is a key parameter that indicates how well a heat sink can dissipate heat. Lower thermal resistance is desirable as it means the heat sink can transfer heat more effectively from the component to the ambient environment .
  • Size and Weight Constraints: The physical dimensions and weight of the heat sink must be compatible with the PCB design and the overall product. It’s important to ensure that the heat sink fits within the designated space and does not add excessive weight that could affect the product’s design or functionality .
  • Airflow Characteristics: The design of the heat sink should complement the airflow characteristics of the system. Heat sinks with fins or other features that promote air movement can be more effective in dissipating heat, especially in systems where natural or forced convection is used for cooling .
  • Attachment Method: The method of attaching the heat sink to the PCB or component is crucial for effective heat transfer. Common methods include thermal adhesive, thermal tape, or mechanical fasteners. The choice of attachment method can affect the thermal contact resistance and should be chosen to ensure good thermal coupling between the heat sink and the component .

When considering thermal vias in conjunction with heat sinks, the following design guidelines should be taken into account:

Guidelines Describe

Diameter and Spacing

The optimal diameter for thermal vias is 0.30 millimeters, and the optimal distance between vias is 0.80 millimeters for best thermal conductivity.

 

Via Filling

Filling vias with materials like epoxy and capping them with copper can prevent solder from flowing into the holes during the manufacturing process, which can weaken the connections. Additionally, filled vias can improve heat dissipation by enhancing the thermal path.

Number of Vias

The number and position of thermal vias directly impact thermal resistance. Placing vias closer to the heat source can lower thermal resistance and improve heat dissipation more quickly.

5. Improve Airflow & Implementing Cooling Fans

Effective airflow management is essential for maintaining optimal temperatures within PCBs, especially in high-power or densely populated designs. By ensuring adequate ventilation and employing cooling fans, engineers can significantly reduce heat buildup and prevent overheating. Here’s how to approach airflow improvement and cooling fan implementation:

fans-or-blowers-PCB-cooling

Airflow Improvement:

  • Ventilation: Ensure that the PCB is placed in an environment with sufficient ventilation. This is particularly important in enclosed spaces where heat can accumulate quickly. Adequate ventilation allows hot air to escape and fresh, cooler air to enter, facilitating natural convection.

  • Airflow Direction: Design the PCB layout with consideration for the direction of airflow. Components that generate the most heat should be positioned in a way that allows air to flow over them, carrying away the heat.

  • Heat Exhaust Paths: Create clear paths for hot air to escape. This may involve designing vents or cutouts in the enclosure and ensuring that these paths do not impede the flow of air.

Implementing Cooling Fans:

  • Fan Selection: Choose fans that are appropriate for the size and heat dissipation requirements of the PCB. Consider factors such as fan speed, air pressure, and noise level when making a selection.

  • Fan Placement: Position fans in a way that maximizes their effectiveness. Ideally, intake fans should be placed to draw in cool air, while exhaust fans should be positioned to blow hot air out of the enclosure.

  • Blower or Sucker Configuration: Decide whether the fans should be configured to blow air onto the PCB (blower configuration) or to suck air away from the PCB (sucker configuration). The choice depends on the specific thermal requirements and the layout of the PCB.

Cooling Techniques:

  • Air Cooling: This is the most common cooling technique used in PCBs. It involves using fans to circulate air over heat sinks or other heat-dissipating components. Air cooling is effective, cost-efficient, and relatively simple to implement.

  • Liquid Cooling: For high-power PCBs or those with particularly high thermal loads, liquid cooling can be considered. This involves circulating a coolant through a heat exchanger or a cold plate that is in contact with the PCB. Liquid cooling is more complex and expensive than air cooling but can handle significantly higher heat loads.

6. Use Thermal Interface Materials (TIM)

Thermal Interface Materials (TIMs) are essential in enhancing heat transfer between components and heat sinks or enclosures, thereby reducing thermal resistance and allowing for more efficient heat flow from hot spots. Here are some common types of TIMs and their benefits:

Thermal Interface Materials
  • Thermal Grease: Also known as thermal paste, thermal grease is a semi-solid material that fills the microscopic gaps between a heat source and a heat sink, improving thermal contact and heat transfer . It is made of a polymer matrix filled with conductive particles, and its effectiveness lies in the intimate contact between the filler particles .
  • Thermal Pads: These are pre-formed pads that can be placed between components and heat sinks to provide a reliable and efficient thermal path. Thermal pads are useful for applications where a more controlled and consistent thermal interface is required .

  • Phase Change Materials (PCM): PCMs are substances that absorb and release heat as they change phase (solid to liquid and vice versa). They can provide a more adequate solution for thermal management, especially in applications where temperature cycling occurs. PCMs can absorb heat during the day and release it at night, helping to maintain a nearly constant temperature .

  • Thermal Adhesives: These are used to bond components to heat sinks or other surfaces while also providing a thermally conductive path. Thermal adhesives can be particularly useful in applications where a permanent bond is required and where they can help to absorb strain resulting from the mismatch of coefficients of thermal expansion (CTE) .

7. Design Multilayer PCBs

Multilayer PCBs offer significant advantages when it comes to thermal management, providing more avenues for heat dissipation and better overall heat distribution. Here’s how multilayer PCBs can contribute to improved thermal efficiency:

Multilayer PCB Thermal Management
  • Ground or Power Planes: Incorporating ground or power planes in a multilayer PCB design creates additional thermal conduction paths. These planes can act as heat spreaders, distributing heat more evenly across the PCB and reducing the risk of localized hotspots.
  • Improved Thermal Conduction: Multilayer PCBs allow for better thermal conduction due to the increased number of copper layers. Copper is an excellent conductor of heat, and having more layers can help to draw heat away from components more effectively.

  • Heat Distribution: By strategically placing ground and power planes, engineers can create a more uniform heat distribution across the PCB. This can help to prevent heat buildup in any one area, which is particularly important for high-power or densely populated PCBs.

  • Thermal Vias: Multilayer PCBs facilitate the use of thermal vias, which can connect different layers and provide additional pathways for heat to escape. These vias can be filled with thermally conductive materials to further enhance their heat transfer capabilities.

  • Component Placement: With more layers available, there is greater flexibility in component placement. Heat-generating components can be placed in areas where heat can be more easily dissipated, such as near the edges of the PCB or in areas adjacent to heat sinks.

  • Layer Stackup Planning: Careful planning of the layer stackup in a multilayer PCB can help to minimize thermal resistance and maximize heat transfer. This involves considering the placement of signal, ground, and power layers to optimize both electrical performance and thermal management.

  • Material Selection: Multilayer PCBs also provide the opportunity to use different materials with varying thermal conductivities in different layers. This can be tailored to the specific thermal management needs of the PCB.

How You Can Identify PCB Thermal Issues?

How You Can Identify PCB Thermal Issues

Even with a well-designed PCB, thermal issues can still occur. Here’s how you can identify these problems:

Visual Inspection:

  • Look for bulging, burnt, or discolored components.
  • Check for unusual odors from the board.
  • Inspect for dry joints or arcing.

Infrared Camera:

  • Used to identify overheating components and areas.
  • Distinguish between counterfeit or defective parts.
  • Detect PCB tracks with insufficient solder.

Thermal Analysis Tool:

  • Model heat flow patterns and design cooling solutions.
  • Identify potential thermal issues early in the design process.

Conclusion

Effective PCB thermal management is essential for ensuring the reliability and performance of your electronic devices. Thermal issues should be a top priority from the start of the design process. You can effectively reduce PCB heat by applying the techniques we discussed earlier. As electronic devices become smaller and more complex, PCB thermal management will present even greater challenges, making it crucial for you as a designer to master these techniques. 

Visit FSCircuits for more information on how to ensure your custom PCB layout excels in safety and thermal efficiency. Need expert advice on thermal management for your PCB? Contact us today for personalized advice or to request a quote.

FAQs

You can design a thermally stable PCB by optimizing component placement, using thicker copper layers, adding thermal vias, and integrating heat sinks to manage heat dissipation effectively.

Techniques include using thermal vias, heat sinks, thicker copper, thermal interface materials, and ensuring proper airflow and spacing between components.

You can use thermal modeling software to simulate heat flow, identify hotspots, and optimize component layout, cooling solutions, and design heat sinks for better thermal performance.

Yes, convection cooling is effective, especially when combined with proper ventilation or fans, as it helps dissipate heat from the board.

A thermally optimized IC manages heat more efficiently by using materials and designs that reduce heat buildup and improve thermal dissipation, ensuring stable performance.

Yes, with proper thermal management techniques like thicker copper layers, thermal vias, and heat sinks, PCBs can handle high power applications.

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