For all switching power supplies, the layout is an important step in the design, especially at high peak currents and high switching frequencies.
If the layout is not carefully done, the regulator could show stability problems as well as EMI problems.
Therefore, use wide and short traces for the main current path and for the power ground tracks.
To minimize voltage spikes at the converter's output:
Place the output capacitor(s) as close as possible to GND and VOUT, as shown in Figure 12-1.
The input capacitor and inductor should also be placed as close as possible to the IC.
Use a common ground node for power ground and a different one for control ground to minimize the effects of ground noise.
Connect these ground nodes at any place close to the ground pins of the IC.
Junction-to-ambient thermal resistance is highly application and board-layout dependent.
It is suggested to maximize the pour area for all planes other than SW. Especially the ground pour should be set to fill available PWB surface area and tied to internal layers with a cluster of thermal vias.