Obviously, the paper design and topology should be robust and cautious. This should take into account the effects of load and line transients, as well as noise. The designer should also carefully determine the required minimum/maximum values of component parameters to ensure reliable operation, as well as those for critical second and third-tier parameters. SPICE or similar modeling of the design is essential, using realistic, not simplified, models of the components and PC boards and tracks, to verify both static and dynamic performance. Next, the choice of components must be done with conservative bias, with extra margin in both initial and long-term values for many of their specification values. Finally, the layout must accommodate the fact that most supplies are dealing with significant current flows, on the order of 10, 20, or more amps. That means that PCB tracks must be kept short to minimize voltage drop, extra-thick copper cladding may be needed, and bus bars may also be a good idea. Board lands need to be large enough for components and current, and through-holes need sufficient size and plating. None of these factors show up on the circuit schematic. Finally, thermal analysis of the design and its physical implementation is critical.