Data Sheet

Ethernet Controller I210 —Design Considerations
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Minimizing the amount of space needed for the Ethernet LAN interface is important because other
interfaces compete for physical space on a motherboard near the connector. The Ethernet LAN circuits
need to be as close as possible to the connector.
Figure 12-13.General Placement Distances for 1000 BASE-T Designs
Figure 12-13 shows some basic placement distance guidelines. Figure 12-13 shows two differential
pairs, but can be generalized for a GbE system with four analog pairs. The ideal placement for the
Ethernet silicon would be approximately one inch behind the magnetics module.
While it is generally a good idea to minimize lengths and distances, Figure 12-13 also illustrates the
need to keep the LAN silicon away from the edge of the board and the magnetics module for best EMI
performance.
12.5.6.2 Layout Guidelines for Use with Integrated and Discrete Magnetics
Layout requirements are slightly different when using discrete magnetics.
These include:
• Ground cut for HV installation (not required for integrated magnetics)
• A maximum of two (2) vias
• Turns less than 45
°
• Discrete terminators
Figure 12-14 shows a reference layout for discrete magnetics.
LAN
Silicon
Integrated
RJ-45
w/LAN
Magnetics
Keep LAN silicon 1" - 4" from LAN connector.
Keep silicon traces at least 1" from edge of
PB (2" is preferred).
Keep minimum distance between differential pairs
more than seven times the dielectric thickness away
from each other and other traces, including NVM
traces and parallel digital traces.
Note: Figure 12-13 represents a 10/100 diagram. Use the same design considerations for the two
differential pairs not shown for gigabit implementations.