Using its new IRF6608 and IRF6618 DirectFETs, International Rectifier created a 105-A synchronous buck converter that complies with the VRM 10.x specification. Designed to fit within a 1U assembly, the 0.985- by 3.8-in. demo board implements a five-phase synchronous buck converter (Fig. 1) with a total of 10 FETs (just one control and one synch FET per phase). The converter operates at a switching frequency of 400 kHz (see Fig. 2).