Reduce EMI by determining large alternating currents carrying areas and making them compact, this minimizes radiation and spilling of unwanted signal to other part of your PCB. More of these methods are shown from Linear Technology’s app note.

PC-board layout determines the success or failure of every power supply project. It sets functional, electromagnetic interference (EMI), and thermal behavior. Switching power supply layout is not black magic, but is often overlooked

until it is too late in the design process. Fortunately physics

is on your side. Functional and EMI requirements must

be met, and in a world of trade-offs in power supply unit

layout, what is good for functional stability is good for

EMI. Good layout from first prototyping on does not add

to cost, but actually saves significant resources in EMI

filters, mechanical shielding, EMI test time and PC board

runs. This application note focuses primarily on nonisolated

topologies, but will examine some isolated topologies as

well. You will learn to make the optimum choices regarding

PC-board layout for solid power supply designs.