Proper PCB design and layout is important in a high-current, fast-switching circuits (with high current and voltage slew rates) to assure appropriate device operation and design robustness. As expected, certain issues must be considered before designing a PCB layout using the LM5145. The high-frequency power loop of the buck converter power stage is denoted by #1 in the shaded area of Figure 11-1. The topological architecture of a buck converter means that particularly high di/dt current flows in the components of loop 1, and it becomes mandatory to reduce the parasitic inductance of this loop by minimizing its effective loop area. Also important is the gate drive loops of the low-side and high-side MOSFETs, denoted by 2 and 3, respectively, in Figure 11-1.

Figure 11-1 DC-DC Regulator Ground System With Power Stage and Gate Drive Circuit Switching Loops