As we have seen, preventing a PCB temperature rise is critical. But how can you reduce heat in a PCB?These are 5 common causes of high heat in a PCB:
1. Component Malfunction Causing Dissipation
One common cause of high heat in a PCB is that one component within the PCB malfunctions and dissipates, failing to generate the amount of power it typically produces. When this happens, the surrounding components have to generate more power to compensate. Generating more power leads to the risk of overheating.
2. Through-Hole Interference
Through-hole components and heat-sink components are the components of the PCB that supply power. They generate heat and dissipate it into the air. If a heat sink is soldered incorrectly, or if a different component of the PCB is interfering with the through-hole, the other components will generate more heat than usual to compensate. This scenario also leads to a risk of overheating.
3. Surface-Mount Device Distance
Surface-mount devices (SMDs) connect to the PCB in the same way through-hole components do. They allow for a smoother flow of current through the through-hole and heat-sink components. But the through-hole components and the SMDs must be positioned at the correct distance from one another. If they are too far away, the current will have farther to travel. The extra time it takes the current to travel can cause the receiving components stay cool for too long. When that happens, other components may overheat to compensate.
4. High-Frequency Circuits
High temperatures are particularly likely in applications that make use of high-frequency circuits. The reason is that the generation of more power naturally produces more heat.
Radio-frequency circuits, for example, represent a fast-growing sector in PCB engineering. These circuits are highly complex but have many useful applications, from wireless security in medical and industrial products to smart phones. These high-frequency circuits tend to generate tremendous amounts of heat, so special design techniques are necessary for these types of PCBs.
5. Lead-Free Solder
As a whole, the PCB industry is moving toward the restriction of hazardous substances (RoHS). RoHS PCBs use lead-free solder, and lead-free solder requires high temperatures so it can flow freely.