2.4.1 Buck Design Considerations
The buck regulator runs at a fixed frequency of 3 MHz nominal, and the inductor and VCORE capacitor are sized accordingly for the buck's control loop performance. Additional parasitic resistance and inductance from the PCB pads and traces can shift the operating parameters and cause instability under certain conditions. Therefore, it is important to minimize all related trace lengths and compact the buck layout as much as possible. It is recommended to place all components on the same side of the PCB as the dsPIC device. If the same side is not physically possible, buck components can be placed on the opposite side with the same goal of minimal trace length and parasitics. An example layout is shown in Figure 2-3.