Page 217 - Make Your Own PCBs with EAGLE from Schematic Designs to Finished Boards

FIGURE 9-5 Critical connections on the LM2596S.

As the note in the datasheet states, a ground-plane construction is ideal, and we will use this for
much of the power-supply area, with some short and thick tracks for the areas not connected by the
ground plane.

We will use a ground plane over the whole bottom layer and a second ground plane around IC2
D1, C1, and C2. The inductor does not have a connection to GND because it will be connected to
pins of IC2, which must be on the top layer; thus there is little point in extending the ground plane up
to L1. Figure 9-6 shows the board with the two ground planes added. Note how I have added a grid

of vias to link the two ground planes.