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60 DESIGN007 MAGAZINE I MARCH 2024 conductivity and low CTE mismatch com- pared to copper. • Heavy copper: As power and temperature requirements increase, the incorpora- tion of thicker copper layers and traces emerges as a strategic approach to effi- ciently disperse heat across the board. Heavy copper PCBs, characterized by copper thicknesses in the 4-to-10-ounce range, not only enhance dissipation, but also increase current carrying capacity and bolster mechanical strength. ese PCBs empower the use of high-performance, high-temperature components, such as those built on silicon carbide (SiC) or gal- lium nitride (GaN), ensuring the realiza- tion of their full high-temperature poten- tial without the risk of circuit failure. Heavy copper PCBs, while larger and heavier than standard PCBs, deliver mark- edly superior thermal perfor- mance. • Insulated metal substrate (IMS): Also called metal core PCBs, these boards are built with a metal base or core layer that serves as a heat sink or heat spreader. Aluminum is the prevalent choice, being more cost-effective than copper, though it is essential to note that aluminum is less resistant to corrosion compared to copper. IMS PCBs are constructed with thermal vias, which enable heat to move from top- side components to the bottom-side base metal. Moreover, the metal layer imparts exceptional hardness and strength to the PCB, while also functioning as an electro- magnetic shield and a ground layer. Choosing a heat spreading PCB technology for a specific high-thermal application involves carefully balancing material properties with design requirements. Most oen, high thermal loads can be effectively managed through the utilization of one of these specialty PCB con- struction methods. Active Cooling Until now, I have exclusively explored pas- sive measures of heat management in elec- tronic systems. However, high thermal loads can't always be managed with passive methods alone. In such cases, adding an active cooling approach is required. is may entail the use of fans, water cooling systems, or heat pumps. While active methods contribute to increased size and complexity of the system, they can offer significant temperature reductions pre- cisely when and where they are needed most. Functional Testing e final step in the design of electronic systems is functional testing of physical prototypes. During this phase of the process the entire PCB assembly is vali- dated, verifying that the device performs as intended and meets all of the design and regula- tory requirements. ermal cycling and thermal shock tests are performed to deter- mine reliability in environ- ments with sudden extreme changes in temperature. Data gathered helps engineers understand the product's operating temperature limits and provides information that can be used to extrapolate the product's potential lifespan. Given the fast pace and extreme competition in the electronics industry, I strongly advocate selecting a manufacturer capable of produc- ing rapid prototypes. is strategic choice can condense prototype fabrication time from sev- eral weeks to a mere few hours. Expedited pro- totyping accelerates the final stages of product development, enabling an agile release of the product to the market. High thermal loads can't always be managed with passive methods alone.