Power And Ground Connections; General Power And Ground Plane Considerations; Figure 122. Ground Plane Separation - Intel Pentium 4 Design Manual

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9.9.2.2

Power and Ground Connections

Some rules and guidelines to follow for power and ground connections:
• All VCC pins should be connected to the same power supply.
• All VSS pins should be connected to the same ground plane.
• Use one decoupling capacitor per power pin for optimized performance.
• Place decoupling as close as possible to power pins.
9.9.2.2.1

General Power and Ground Plane Considerations

To properly implement the common mode choke functionality of the magnetics module the chassis
or output ground (secondary side of transformer) should be separated from the digital or input
ground (primary side) by a physical separation of 100 mils minimum.

Figure 122. Ground Plane Separation

Good grounding requires minimizing inductance levels in the interconnections and keeping ground
returns short, signal loop areas small, and power inputs bypassed to signal return, will significantly
reduce EMI radiation.
® ®
Intel Pentium 4 Processor / Intel
Magnetics Module
Separate Chassis Ground Plane
®
850 Chipset Family Platform Design Guide
0.10 inches minimum separation
Ground Plane
Ground_Plane_Separation
I/O Controller Hub 2
169