Due to the increasing power consumption of data centers, efficient dc power distribution systems have become an important topic in research and industry over the last years and according standards have been adopted. Furthermore the power consumed by telecommunication equipment and data centers is an economic factor for the equipment operator, which implies that all parts of the distribution system should be designed to minimize the life cycle cost, i.e. the sum of first cost and the cost of the power conversion losses. This paper demonstrates how semiconductor technology, chip area, magnetic component vol-umes and switching frequency can be selected based on life cycle cost, using analytical and numerical optimizations. A three-phase buck-type PFC rectifier with integrated active filter for 380V dc distribution systems is used as an example system, which shows that a peak efficiency of 99% is technically and economically feasible with state-of-the-art SiC MOSFETs and nanocrystalline or ferrite cores. Measurements taken on an 8 kW, 4 kWdm-3 hardware prototype demonstrate the validity and feasibility of the design.