This paper will review the state-of-the-art of high-frequency, highly integrated, inductive, low power DC-DC converters. This study aims to bring out the actual trade-offs between efficiency, level of integration, conversion ratio, technology … The analysis will focus on the electrical and the physical/technological aspects of DC-DC converters. The context of this study is the design and manufacturing of a high frequency (200 MHz), highly integrated DC-DC converter, based on the ultimate association in 3D of an active die to an interposer of passive devices.