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Chapter 6 Power and Signal Distribution
6.3.2 LOW VOLTAGE PRODUCTION/DISTRIBUTION
Voltages less than 3.3 VDC including processor core (VccP) voltage are produced through
regulator circuitry (Figure 6-4) on the system board.
VccP (see text)
DDR DIMMs
+3.3 VDC
+12 VDC
AGP Bus
VDDQ (1.5 VDC)
AGP
PWR
+5 VDC
+1.8 VDC
+1.4 Ref
2.5 S3 VDC
DDR
Power
Circuitry
+3 AUX
3.3 VDC
3.3
DIMM
Circuit
DIMMs
+5 AUX
+3.3 VDC
+5 VDC
Processor
VID0
VID1
VID2
VID3
VID4
+12 VDC
+12.8 Vcpu
Regulator
Circuit
Power Supply
Processor
igure 6–4. Low Voltage Supply and Distribution Diagram
ng of
gnals VID4..0 by the processor. The possible voltages available are listed as follows:
F
The VccP regulator produces the VccP (processor core) voltage according to the strappi
si
VID 4..0
VccP VID 4..0 VccP VID 4..0 VccP
00000 2.05 VDC 01011 1.50 VDC 10110 2.90 VDC
00001 2.00 VDC 01100 1.45 VDC 10111 2.80 VDC
00010 1.95 VDC 01101 1.40 VDC 11000 2.70 VDC
00011 1.90 VDC 01110 1.35 VDC 11001 2.60 VDC
00100 1.85 VDC 01111 1.30 VDC 11010 2.50 VDC
00101 1.80 VDC 10000 3.50 VDC 11011 2.40 VDC
00110 1.75 VDC 10001 3.40 VDC 11100 2.30 VDC
00111 1.70 VDC 10010 3.30 VDC 11101 2.20 VDC
01000 1.65 VDC 10011 3.20 VDC 11110 2.10 VDC
01001 1.60 VDC 10100 3.10 VDC 111
11 No CPU
01010 1.55 VDC 10101 3.00 VDC -- --
Compaq Evo and Workstation Personal Computers
Featuring the Intel Pentium 4 Processor
Second Edition- January 2003
6-8