Change part locations,
and importantly the orientations, to make the high current flow along a
short and straightforward path. Prevent unnecessary zigzag
patterns.
Try to avoid using via
holes on the high current path unless they are necessary. When using
vias, you need to use an adequate number of via holes.
There is a tradeoff to
make among the number of, and spacing between, the via holes. Too many
via holes crowded in a small area can hinder current flow due to the
loss of copper area.
Find a location for the
controller IC, not too far from the MOSFETs that it will drive. The location
needs to allow a decent AGND polygon to accommodate all control signals. The
AGND and PGND connection point needs to be the thermal pad. Place the critical
control components next to the controller IC, and visualize the signal routes.
Move the components and change their orientations to simplify the routing
Route high current traces as well
as the critical control signal paths before routing other traces.
Optimal layout of the switch mode
power supply is always the result of iterations. There is no short cut that can
lead to an optimal layout in one shot.