·Prioritize layout and routing designs based on the power management IC’s recommendations.
· Analyze the schematic to examine the power supply’s input, output, and feedback paths, and identify the main pathways for power flow.
· Place the power management IC in an appropriate location according to the recommendations in the datasheet. Begin by placing components along the main input/output pathways. Pay special attention to the handling of return paths during layout; return paths should be as short as possible.
· When placing components, aim for a compact layout to minimize power paths. Ensure sufficient space is left for via placement and copper routing to meet the current-carrying capacity requirements of the power module’s input and output channels.
· When placing filtering components, follow the principle of placing larger capacitors before smaller ones along the power path.
· For switching power supplies with multiple outputs, position adjacent inductors perpendicular to each other whenever possible. Place large inductors and capacitors on the main component side whenever possible.
· Avoid running input and output traces parallel to each other whenever possible. Thicken the ground traces between the input and output to prevent feedback coupling.
· Use copper pads for routing power input/output paths; the width of the copper pads must accommodate the magnitude of the power current. Minimize the number of vias used to switch between layers for input/output paths. When vias are used to switch layers, consider the placement of filtering components: input vias should be placed before the filtering components, and output vias after them.
· Feedback paths must be routed away from interference sources and high-current planes; generally, use traces 10 mil or wider to connect to the output filter capacitor.
· Signal interconnects within the switching power supply module should be as short and wide as possible, typically widened to 10 mil or more (but not wider than the heat sink pad).
· The large heat sink pad in the center of the switching power supply generally requires heat sink ground vias. Additionally, the holes on the heat sink pads must be opened on both sides to facilitate heat dissipation. Typically, openings are created on the back of the heat sink pads to increase the heat dissipation area and improve efficiency.
· Avoid routing traces beneath inductors in the switching power supply module; the copper layer beneath them must be etched away (down to the silkscreen level). If traces are present near the inductor, the signal lines must be grounded.