Some system design guidelines for improved ESD performance are grouped in three categories, Guidelines for layout & PCB design, Consideration for external connectors, and Consideration for enclosures. Starting with layout and routing first, try to minimize the loops and ground planes to reduce the possibility of inductive coupling. Providing return paths or continuous ground planes is recommended whenever feasible. It is also recommended to separate power domains by providing isolations between MCU and switching power supplies using components such as ferrite beads and common mode chokes. Whenever possible, physical isolation can be provided by separating power domains in different layers. The designer can use decoupling caps to improve the ESD performance, but keep in mind that they are more effective when placed in close proximity of the MCU pins. This is illustrated in the figure shown here on the screen.