This paper targets at proposing a 48V to 3.2V(15x) Matrix Autotransformer Switched-Capacitor DC-DC Converter for data center applications. On the high voltage side, the circuit is similar to STC’s high voltage side structure. On the low voltage side, the circuit adopts the current doubler circuit like LLC’s secondary side to replace STC’s full bridge circuit. By reconfiguring the structure, theoretically, the transformer’s winding loss can be decreased to 44.9% when compared with LLC’s if the core size is the same, and the low voltage side devices’ conduction loss can be decreased by half when compared with STC’s. In this paper, the detailed power loss comparison among STC, LLC and proposed MASC is made, and a 15x prototype is built to verify the feasibility of the proposed circuit. The maximum measured efficiency can reach 98.75% without gate driver and chips’ power loss, and the maximum measured efficiency is 97.6% when the gate driver including chips’ power loss is included.