Intel® Pentium® 4 Processor in the 478-Pin Package Processor Power Distribution Guidelines
11.1.6
FMB2 Four–Phase Layout (4-Layer Board)
All four layers in the processor area should be used for power delivery. Two layers should be used
for VCC_CPU and two layers should be used for ground. Traces are not sufficient for supplying
power to the processor due to the high current and low resistance required to meet the processor
voltage specifications. To satisfy these requirements shapes that encompass the power delivery
part of the processor pin field are required. The following figures show examples of how to use
shapes to delivery power to the processor.
Figure 153. Top Layer Power Delivery Shape (VCC_CPU)
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Pentium
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850 Chipset Family Platform Design Guide
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