An often overlooked aspect of designing switch mode power supplies is their printed circuit board layout. For this reason, Altera makes it easy by supplying Gerber files with an optimized recommended layout of not only the top layer of the board, but the bottom and inner layers. As can be seen here for the EN29A0QI layout, the local input and output filter capacitors are located on the top side of the board and close to the package, and the compensation components in the control loop are located close to the internal error amplifier’s input pin VFB. Altera always recommends that the system ground plane be located on layer 2 below the surface layer with many vias connecting the large thermal pad on the bottom of the package to this system ground plane. Less critical components can be located on the bottom of the board. More details concerning layout guidelines can be found on the datasheet. Sometimes it is not practical or even possible to adhere to all of the layout guidelines, but implementing them as best as possible will yield the best overall performance and helps to guarantee first-pass success.