FAN5031

FAN5031 8-Bit Programmable, 2 to 4 Phase, Synchronous Buck Controller

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FAN5031 8-Bit Programmable, 2 to 4 Phase, Synchronous Buck Controller

March 2006

FAN5031 8-Bit Programmable, 2 to 4 Phase, Synchronous Buck Controller
Features
Selectable 2, 3, or 4 phase operation at up to 1MHz

Description
The FAN5031 device is a multi-phase buck switching regulator controller, that is optimized to convert a 12V input supply to the processor core voltage required by high performance Intel processors. It has an internal 8-bit DAC that converts a digital voltage identification (VID) code, that is sent from the processor, to set the output voltage between 0.5V and 1.6V in 6.25 mV steps. It outputs a PWM signals to external MOSFET drivers that, in turn, drive the switching power MOSFETs. The switching frequency of the design is easily programmable by a single resistor value and the number of phases can be programmed to support 2, 3, or 4 phase applications. The FAN5031 also includes programmable no-load offset and droop functions to adjust the output voltage as a function of the load current, as required by the Intel specifications. The FAN5031 also provides an accurate and reliable short circuit protection function with an adjustable over current set-point. The FAN5031 is specified over the commercial temperature
range of 0 C to 85 C and is available in a 40-lead MLP package.

per phase 7.7mV worst-case differential sensing error over temperature Active current balancing between the output phases Power good and Crowbar blanking supports on-the-fly VID code changes 0.5V to 1.6V output Fully compliant to both Intel s VR10 and VR11 specifications Selectable VR10 extended (7 bit) and VR11 (8 bit) VID tables Programmable soft start ramp Programmable short circuit protection and latch-off delay

Applications
Desktop PC/Server processor power supplies for

existing and next generation Intel processors VRM modules

Ordering Information
Part Number
FAN5031MPX Lead free part

Temperature Range
0 C to 85 C

Package Type
MLP-40

Packing Method
Tape and Reel

Quantity per Reel
3,000

2006 Fairchild Semiconductor Corporation

www.fairchildsemi.com

FAN5031 Rev. 1.0.1