Compared to the traditional resonant DC-DC Converter, the Enhanced Fault-Tolerant DC-DC converter has many advantages, such as high efficiency, low current ripple and high voltage gain. In order to improve the power density of the enhanced fault-tolerant DC-DC converter since it uses many passive components for power conversion, a passive integrated unit with the flexible multi-layer foil (FMLF) integration technique is proposed in this paper which integrates two series resonant inductors, two series resonant capacitors, two parallel resonant inductors, two transformers and four filter capacitors into an E-E core geometry. Furthermore, the construction, flux analysis and parameter design of the proposed integrated unit are introduced in detail. Finally, a simulation model based on Maxwell/Ansoft to prove the feasibility of this idea.