Electronic devices may contain electrical systems in which electrical components are mounted on a substrate such as a printed circuit board. The electrical components may include surface mount technology components. Multiple surface mount technology components may be stacked on top of each other and beside each other to form an electrical component that minimizes the amount of area that is consumed on a printed circuit board. Noise suppression circuits and other circuits may be implemented using stacked surface mount technology components. Surface mount technology components placed on the printed circuit board may be pushed together and subsequently injection molded to form packed component groups. An integrated circuit may be mounted to the printed circuit board via an interposer and may cover components mounted to the printed circuit board. An integrated circuit may be mounted over a recessed portion of the printed circuit board on which components are mounted.