Intel EP80579 Manual page 228

Gigabit Ethernet (GbE) Interface—Intel
• Gigabit Ethernet signals must be ground referenced.
• Route all traces over continuous GND planes, with no interruptions. Avoid crossing
over anti-etch if at all possible. Any discontinuity or split in the ground plane can
cause signal reflections and must be avoided.
• Minimize layer changes. Use a maximum of 4 vias per GbE trace for microstrip or a
maximum of 6 vias for stripline. Via count includes thru-hole connector as an
effective via. Use a maximum of six vias for stripline in order to connect to the AC
decoupling capacitors. If a layer change is necessary, ensure that trace matching
for either the transmit or receive pair occurs within the same layer.
• Do not route GbE traces under crystals, oscillators, clock synthesizers, magnetic
devices, or ICs that use and/or duplicate clocks.
®
Intel EP80579 Integrated Processor Product Line
Order Number: 320068-005US
®
EP80579 Integrated Processor Product Line
May 2010
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