Fairchild Semiconductor International announces the FAN5091 Two-Phase Single-Chip Synchronous Buck Controller with integrated high-current Super Drivers. It demonstrates 10% gains in conversion efficiency compared to 3-phase solutions. The features offered by FAN5091 simplify power supply designs requiring 69A for Willamette VRM9.0, Pentium IVÔ CPUs or the 50A required for Athlon K7 CPU-based systems. Integrated drivers for external power MOSFETs result in designs with reduced parts count and board space, and increased reliability.

Operating from a single 5V supply, the FAN5091 features Programmable Active DroopÔ , and achieves 100nsec transient response when operating with minimal output capacitance. A 5-bit VID DAC allows precision dynamic adjustment of the output voltage between 1.10V to 1.85V. An E* mode which improves efficiency under light load conditions is provided, allowing designers to meet the Federal Energy-Star power conservation guidelines. Other features include Power Good indication, Output Enable/Soft Start, Under-voltage lockout (UVLO), over-voltage protection, and adjustable current limiting.

Fairchild Semiconductor Customer Response Group, Phone: 888-522-5372; Fax 972- 910-8036.

The FAN5091 is a synchronous multi-slice DC-DC controller IC that provides a programmable output voltage for all high-performance processors. It drives N-channel MOSFETs and offers over-current protection using MOSFET sensing. Two interleaved synchronous buck (or opposing) regulator slices with built-in current sharing operate 180° out of phase to provide the transient response time needed to satisfy high current applications while minimizing external components. The controller features remote voltage sensing, and Programmable Active Droop™ voltage positioning -- for 100nsec converter transient response with minimum output capacitance. It has integrated high-current gate drivers, with adaptive delay gate switching, eliminating the need for external drive devices.

The FAN5091 uses a 5-bit D/A converter to program the output voltage from 1.10V to 1.85V in 25mV steps with an accuracy of 1%. The programmable frequency ranges from 200KHz to 2MHz. The FAN5091 uses a high level of integration to deliver load currents in excess of 50A from a 5V source. It also offers integrated functions including Power Good, Output Enable/Soft Start, under-volt-age lockout, over-voltage protection, and adjustable current limiting with independent current sense on each slice.

The FAN5091 is available in a 24-pin TSSOP package. An Evaluation Board is available.

Price: U.S. $3.75 each (1,000 pieces) Samples now and production quantities in 7-8 weeks ARO.

Datasheets:
www.fairchildsemi.com/ds/FA/FAN5091.pdf (linked above) or www.fairchildsemi.com/pf/FA/FAN5091.html#Dat