Thermal Issues in High-Density Circuit Boards

In a world of miniaturization and increasing demand for high-performance, high-density circuit boards, thermal issues can be difficult to address. However, with careful planning and collaboration with PCB manufacturers, a designer can mitigate these issues.

Electronic components generate a considerable amount of heat during operation, and the level of heat production is proportional to their power consumption. This heat can cause the substrate to deform, degrade or even break down over time. Considering that a standard FR-4 PCB has relatively low thermal conductivity, implementing adequate thermal management is crucial to the lifespan of the board and its components.

The use of copper elements for ground and power planes in the PCB’s core is a good start, as they help disperse excess heat throughout the board. Another option is the addition of copper structures, called thermal vias, which provide a path for heat to disperse away from the active components. When used in conjunction with the other thermal management techniques, these vias can significantly reduce temperature levels in critical areas and eliminate hot spots.

How to Mitigate Thermal Issues in High-Density Circuit Boards

It is also important to verify that a design’s copper-to-edge clearance meets the requirements of the PCB fabrication process. Insufficient clearance can lead to EMI and crosstalk. Additionally, signal integrity can be impacted by poor component placement and routing, especially in hdi circuit board designs.

Insufficient thermal pathways can also result in localized hotspots and elevated temperatures, which can affect the performance of a circuit board. The location and number of hotspots are influenced by the type of component, its package size, and how it’s placed on the board. High-powered components such as resistors, voltage regulators, and power FETs produce a lot of heat, so it’s important to place them in locations that are conducive to their function.

Smaller components are more sensitive to heat and may fail if they reach an unsafe operating temperature. This is particularly true for small packages such as SOT-23 and TO-220 MOSFETs, which have a limited surface area for heat dissipation. Increasing the size of these components or placing them in higher-powered locations can increase their ability to dissipate heat, which will help prevent overheating and potential failure.

The materials and the design of a circuit board’s layers will impact its cost, as well as its ability to withstand temperature. Choosing a material with adequate thermal properties, mechanical stability and durability is essential to the longevity of the board. FR-4 is one popular choice for high-density applications, but there are other options available as well.

Finally, the selection of a suitable surface finish is also important. Options include HASL, immersion silver, ENIG and OSP, each of which has unique characteristics that can influence the solderability and life of an HDI PCB. By choosing the best finish for your needs, you can ensure that the PCB’s surface is ready for assembly and can withstand the demands of its intended use.