For an electronic engineer, circuit design is a fundamental skill. However, even if the circuit schematic is flawless, failing to understand and address common issues and challenges that arise when converting it into a PCB can significantly compromise the system. In extreme cases, it may cause the design to fail entirely. To avoid engineering redesigns, improve efficiency, and reduce costs, I will outline the most common issues and their solutions.

1. **Component Selection and Layout**

The specifications of each component vary, and even components from different manufacturers that are technically the same may have different characteristics. Therefore, when selecting components during the design phase, it’s essential to consult with suppliers to understand their specific characteristics and how they could impact the design.

In today’s electronic product design, selecting the right memory is particularly important. With the continuous evolution of DRAM and Flash memory, staying ahead of the rapidly changing external memory market has become a major challenge for PCB design. Currently, DDR3 holds around 85%-90% of the DRAM market, but it is expected that DDR4 will increase from 12% to 56% by 2014. As a result, designers must closely monitor the memory market and maintain strong communication with manufacturers to keep up with these changes.

**Component Overheating and Burnout**

Another critical issue is the risk of components burning out due to overheating. For components that generate significant heat, proper thermal management calculations are essential, and their placement on the PCB needs careful consideration. When numerous components are placed in close proximity, they can generate excess heat, leading to problems such as solder mask deformation, separation, or even the ignition of the PCB. Therefore, layout and design engineers must collaborate to ensure proper thermal management and sufficient spacing between components.

**PCB Size Considerations**

The PCB size is a key factor during the layout process. If the PCB is too large, the trace lengths will increase, leading to higher impedance, reduced noise immunity, and higher costs. On the other hand, if the PCB is too small, it will struggle with heat dissipation, and the adjacent traces could interfere with each other. Once the PCB size is determined, the next step is to position the special components, followed by the layout of the remaining components based on the functional blocks of the circuit.

2. **Cooling Systems**


1. The design of the heat dissipation system involves selecting appropriate cooling methods and heat dissipation components, as well as considering the coefficient of thermal expansion. Currently, PCB heat dissipation primarily relies on the PCB itself for heat conduction, supplemented by heatsinks and thermal conduction plates.

2. In traditional PCB design, the boards typically use copper-clad epoxy glass fiber substrates or phenolic resin glass fiber substrates, with some instances of paper-based copper-clad boards. While these materials offer good electrical and processing properties, their thermal conductivity is poor. Given the widespread use of surface-mount components like QFP and BGA in modern designs, the heat generated by these components is transferred to the PCB in significant amounts. Therefore, the most effective solution for heat dissipation is to enhance the thermal management capabilities of the PCB itself, which is in direct contact with the heat-producing components, allowing it to conduct or radiate heat more efficiently.

3. When only a few components on the PCB generate substantial heat, a heatsink or heat pipe can be added to the heat source. If the temperature remains high and cannot be reduced, a fan-assisted heatsink may be used. When numerous components generate heat, a larger heat dissipation cover can be employed. This cover is designed to fit snugly over the components, making direct contact with each to facilitate heat dissipation. For high-performance computers used in video and animation production, liquid cooling systems may even be required for effective temperature management.

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