The synchronous buck converter is the DC-DC converter of choice in PC and notebook computers and has been so for many years. This topology provides ease of control and high power conversion efficiencies at a relatively low cost and within a small footprint. One of the keys to success in designing a synchronous buck converter is limiting the shoot-through or cross-conduction current. This phenomenon can cause excessive losses which leads to poor performance and results in low power conversion efficiency. Mathematical formulae will be derived that allow MOSFET and power supply designers to test the suitability of a specific device for its use as a synchronous rectifier in this converter.