The board layout for the TPS54231EVM-372 is shown in Figure 3-1 through Figure 3-3. The topside layer of the EVM is laid out in a manner typical of a user application. The top and bottom layers are 2-oz. copper.

The top layer contains the main power traces for V_IN, V_OUT, and VPHASE. Also on the top layer are connections for the remaining pins of the TPS54231 and a large area filled with ground. The bottom layer contains ground and a signal route for the BOOT capacitor. The top and bottom and internal ground traces are connected with multiple vias placed around the board including ten vias directly under the TPS54231 device to provide a thermal path from the top-side ground plane to the bottom-side ground plane.

The input decoupling capacitors (C1, C2, and C3) and bootstrap capacitor (C4) are all located as close to the IC as possible. In addition, the voltage set-point resistor divider components are also kept close to the IC. The voltage divider network ties to the output voltage at the point of regulation, the copper V_OUT trace past the output capacitor C10. For the TPS54231, an additional input bulk capacitor may be required, depending on the EVM connection to the input supply.

Figure 3-1 TPS54231EVM-372 Top-Side Layout

Figure 3-2 TPS54231EVM-372 Bottom-Side Layout

Figure 3-3 TPS54231EVM-372 Top-Side Assembly