PCB temperature: Tips regarding improving the thermal management of PCBs

Thermal management is of utmost importance while designing PCBs. This is because the temperature of PCBs can guarantee the reliability, performance, and longevity of PCBs and the electronic equipment of which they are an integral component. Thus, enhanced Printed Circuit Board heat management is a necessity for reliable operation and to protect against damage to electronic components.

In the upcoming chapter, we will discuss several approaches to strengthen PCB temperature management.

Reasons of heat generation

There are various reasons why heat is produced on a printed circuit board (PCB). For example, power dissipation, joule heating, inefficient power conversion, high-frequency operation, and insufficient thermal management. The functionality, dependability, and durability of electronic components on a PCB can all be adversely impacted by excessive temperatures. To effectively control temperature and guarantee the PCB operates at its optimum level, proper thermal design is also mandatory.

Tips for enhancing thermal management in Printed Circuit Board

· Tips 1: Component Placement

One strategy for significantly reducing heat concentration is to arrange components on the PCB with a proper design and location. To be specific, the heat-generating components should be positioned near fans or heat sinks, or other cooling gadgets, and in regions with adequate ventilation. Moreover, we should also make sure that parts with various heat requirements are not positioned too near to one another. To be specific, it is not possible to put components that have a high power or thermal burden next to one another. They have to be separated by at least 20 mm. It can prevent excessive local heat load on the PCB in this way. And placing the components too close will not only cause thermal burden, but may also cause interfere problems. This can lead to noise, signal integrity and other issues. Furthermore, we may arrange high-power parts in a group and make sure there's enough space between them to allow for sufficient heat dissipation.

In other words, elevated temperatures have the potential to hasten ageing, deteriorate functionality, and possibly cause untimely failures. Longevity and dependable operation of components are ensured by maintaining them within their safe operating temperature range through effective thermal management.

· Tips 2: Heat Sink Selection - Passive cooling method

A heat sink is a passive thermal management device that employs thermal conduction to absorb and dissipate heat produced by electronic elements on PCBs. Heat sinks are typically made from a thermally conductive material, such as aluminum or copper, and have fins or other extended surfaces. These fins significantly increase the surface area available for heat transfer. Therefore, designers can increase the effective cooling surface area by attaching a heat sink to the component, which can transfer heat to the surrounding air more efficiently.

Also, by expanding the surface area of the heat sink, convection cooling is encouraged. The surrounding air comes into contact with the fins or expanded surface as heat is transmitted to the heat sink. This promotes improved convection, which aids airflow and heat dissipation. In other words, heat is removed by the flowing air, which lowers the radiators and their connected components' temperature. Moreover, we can choose to use a high-quality thermal interface material such as thermal paste or thermal pad between the component and the heat sink. It is because the TIM fills microscopic air gaps and enhances thermal conductivity, which improves heat transmission between components and heat sinks. In addition, to satisfy particular cooling needs, we could occasionally need a heat sink that is specially constructed. To develop and optimize heat sinks for particular applications, we can collaborate with thermal engineers or heat sink manufacturers.

· Tips 3: PCB Material Selection

First of all, it is possible to use materials with high thermal conductivity, which efficiently moves heat away from high-power components. Since copper has such good heat conductivity, it is employed extensively in this situation. Also, copper or aluminum core metal core printed circuit boards (MCPCBs) can improve thermal performance. We can also choose materials with a similar coefficient of thermal expansion to the component, thus minimizing thermal stress and preventing mechanical failure due to temperature changes. Because when the coefficients do not match, there may be a risk of solder joint failure or component damage. Moreover, while designing PCBs, designers could opt for materials with lower dielectric constants to minimize heat retention. This is because of the fact that materials with a lower dielectric constant facilitate greater heat dispersion and lessen the possibility of hot spots forming.

In Addition, we may also experiment with employing several layers, such as copper planes or power planes, in our PCB design. This is because the heat is dispersed across the PCB by these flat surfaces, which function as effective heat pipes. Furthermore, we can take the material's heat resistance into account while choosing materials. As it gauges how well a substance dissipates heat. In this case, we could go with materials that allow for more effective heat transfer and dissipation by having lower thermal resistance. Also, it is worth noting that if using a heat sink, consider the PCB material and heat sink connection method. Like thermal adhesive or mechanical mounting compatibility. To guarantee a secure and reliable radiator connection, some materials might need to be prepared specifically or have adhesives that work with them.

Overall, when it comes to thermal management, material selection should be consistent with the specific requirements and constraints of the PCB application. Therefore, balancing thermal performance, electrical performance, cost considerations, and other design requirements is incredibly important.

· Tips 4: Keep Traces Short

It's imperative to remember that short traces can aid in temperature control. Why can maintaining a short transmission distance enable the thermal management of PCBs? This is because keeping the transmission distance short reduces resistance, reduces voltage drop, speeds up signal propagation, improves signal integrity, and reduces thermal coupling. To be specific, take reduced resistance as an example, as shorter traces have lower resistance, which reduces power dissipation due to resistive losses. When current flows through a trace, it encounters resistance, which converts some of the electrical energy into heat. So when you keep traces short, you can minimize resistive losses and reduce the amount of heat generated, thereby achieving thermal management. At the same time, if we use longer traces we may be more susceptible to signal distortion, such as signal reflections and crosstalk. These signal integrity issues can lead to increased switching noise and signal degradation. So these issues can be alleviated by keeping traces short, resulting in clearer signals, lower noise, and lower power consumption.

· Tips 5 Copper Pour and Traces

One of the most effective ways to manage PCB thermal management is by increasing the copper and trace width in areas where components generate a lot of heat. The wider copper traces and pours have less resistance. Because the resistance of a trace is directly proportional to its length and inversely proportional to its cross-sectional area. So by increasing the width of a trace, you lower its resistance and minimize resistive losses. This reduces power consumption and subsequently, the heat generated.

Conclusion

In conclusion, by using component placement, heat sink selection, PCB material selection, maintaining traces short, and widening traces, we can control and manage the temperature while designing PCBs. Of course, it is not limited to these above methods, we can also enhance the thermal management of PCBs by placing Vias near heat-generating components, using thermal Vias to connect the thermal pad of a component to inner or outer copper layers, etc... However, thermal management is a complex and multifaceted challenge because PCB design is complex and demanding. Therefore, different technologies and strategies must be implemented according to different situations. In summary, when implementing thermal management techniques, we must consider the thermal characteristics of the component, the operating environment, and the overall system design.