This project aims to design and implement a DC-DC buck converter based on the Three-level Flying Capacitor Converter (3L-FCC) architecture for space applications, namely CubeSat systems, using the Skywater 130nm CMOS technology. In our proposal, the power circuits are fully integrated on-chip, including the power MOSFETs (PM), the flying capacitor (FC) and the gate drivers (GD), to obtain an efficient and compact implementation and contribute with a versatile power electronics building block to the open source IC design community.