10.1.1 General Considerations

Designing for high power density requires to consider noise coupling and thermal management. A four-layer PCB structure is highly recommended to use inner layers to help reduce current loop areas and provide heat-spreading for surface-mount semiconductors.

• Provide internal-layer copper areas to improve heat dissipation of high-power SMDs, particularly for MOSFETs and power diodes.
• To avoid capacitive noise coupling, do not cross outer-layer signals over copper areas with high-frequency switching voltage.
• To avoid inductive noise coupling, keep switching current loops as small as possible, and do not run signal tracks in parallel with such loops.

Figure 54 summarizes the critical layout guidelines, and more detail will be also be further elaborated in the descriptions below.

Figure 54. Schematic with Layout Considerations