Two-Phase Controller Powers Leading-Edge Microprocessors

The new FAN5091 is a two-phase, single-chip, synchronous buck controller with integrated high-current super drivers. Operating from a single 5V supply, the device features Programmable Active Droop and achieves 100 ns transient response when operating with minimal output capacitance. These and other features of the FAN5091 are said to greatly simplify power supply designs requiring 69A for Willamette VRM9.0 Pentium IV CPUs or 50A for Ath-lon K7 CPUs. The company also claims gains in conversion efficiency of over 10% when compared to competing 3-phase solutions. A 5-bit VID DAC allows precision dynamic adjustment of the output voltage between 1.10V to 1.85V, while an E* mode further improves efficiency under light load conditions, allowing designers to meet the Federal Energy-Star power conservation guidelines. The FAN0591 is available in a 24-pin TSSOP package and is priced at $3.75 each/1,000. FAIRCHILD SEMICONDUCTOR INTERNATIONAL, San Jose, CA. (888) 522-5372.