The progress of the advanced computing cores coming from microprocessor manufacturers such as Intel and AMD have necessitated a change in the topology of the switching regulators traditionally used to power these processor cores. Multiphase buck regulators have proven to be the topology of choice for such high-current applications. However, the distributed power system architecture of these computers continue to have a need for other sub-system specific voltages. The HIP6521 was created to complement a multiphase buck controller in creating a complete power solution for the typical Pentium 4 system. Athlon-class processor based systems (AMD) may also benefit from the HIP6521. [1]