FAN5031 Datasheet, PDF (1/3 Pages) Fairchild Semiconductor – 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
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
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 out-
puts 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 off-
set and droop functions to adjust the output voltage as a
function of the load current, as required by the Intel spec-
ifications. The FAN5031 also provides an accurate and
reliable short circuit protection function with an adjust-
able over current set-point.
The FAN5031 is specified over the commercial tempera-
ture range of 0°C to +85°C and is available in a 40-lead
MLP package.
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
1
FAN5031 Rev. 1.0.1
www.fairchildsemi.com