FAN5091

www.fairchildsemi.com

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www.fairchildsemi.com

FAN5091
Two Slice Interleaved Synchronous Buck Converter
Features
Programmable output from 1.10V to 1.85V in 25mV steps using an integrated 5-bit DAC Two interleaved synchronous slices for maximum performance 100nsec response time Built-in current sharing between slices Remote sense Programmable Active Droop (Voltage Positioning) Programmable frequency from 200KHz to 2MHz Adaptive delay gate switching Integrated high-current gate drivers Integrated Power Good, OV, UV, Enable/Soft Start functions Drives N-channel MOSFETs Operation optimized for 5V operation High efficiency mode (E ) at light load Overcurrent protection using MOSFET sensing 24 pin TSSOP package

Description
The FAN5091 is a synchronous multi-slice DC-DC controller IC which provides a highly accurate, programmable output voltage for all high-performance processors. Two interleaved synchronous buck regulator slices with built-in current sharing operate 180 out of phase to provide the fast transient response needed to satisfy high current applications while minimizing external components. The FAN5091 features remote voltage sensing and Programmable Active Droop 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 FAN5091 uses a high level of integration to deliver load currents in excess of 50A from a 5V source with minimal external circuitry. The FAN5091 also offers integrated functions including Power Good, Output Enable/Soft Start, u
nder- voltage lockout, over-voltage protection, and adjustable current limiting with independent current sense on each slice. It is available in a 24 pin TSSOP package.

Applications
Power supply for Pentium IV Power supply for Athlon VRM for Pentium IV processor Programmable step-down power supply

Block Diagram
Bypass 6 5V Reg 12V 18 12V 13 23 5V

OSC

Digital Control

15 12V 17 16 VO 12V 12 11 5V

Digital Control

10 12V 8 9

5-Bit DAC
1 2 3 4 5 24

Power Good
19 PWRGD 21 7 22 ENABLE/SS 20 ILIM

VID0 VID2 VID4 VID1 VID3

DROOP/E GNDA

Pentium is a registered trademark of Intel Corporation. Athlon is a registered trademark of AMD. Programmable Active Droop is a trademark of Fairchild Semiconductor.

REV. 1.0.0 5/10/01