The paper presents a design-oriented analysis of dc-dc converters valid for both periodic and aperiodic operation. Bifurcation and statistical analysis are applied to a peak current mode controlled boost converter. The main benefit of aperiodic (chaotic) converter operation - reduction of electromagnetic interference - is discussed. Periodic and aperiodic behavior are compared. Periodic converter operation exhibits the smallest ripple waveform but the worst (purely discrete) spectrum. Aperiodic converter operation yields a broader spectrum but a larger ripple. Tradeoffs between ripple and spectrum for the practical use of chaotic dc-dc converters are suggested. The paper discusses the choice of the converter's bifurcation parameter from the ripple and spectrum points of view.