Infineon offer a range of synchronous buck regulators, some include PMBus Interface. The DC-DC converters have many features such as Internal LDO, programmable switching Frequency, Integrated MOSFETs and Bootstrap diode and is available in a PQFN package. Applications include Netcom and telecom, desktops, servers, graphic boards and point of load.
Switching Voltage Regulators, International Rectifier