Data Sheet

Design Considerations—Ethernet Controller I210
817
Figure 12-12.I210 10/100 Mb/s Magnetics Module Connections (With CMC)
12.5.6 Layout Considerations for the Ethernet Interface
These sections provide recommendations for performing printed circuit board layouts. Good layout
practices are essential to meet IEEE PHY conformance specifications and EMI regulatory requirements.
Critical signal traces should be kept as short as possible to decrease the likelihood of being affected by
high frequency noise from other signals, including noise carried on power and ground planes. Keeping
the traces as short as possible can also reduce capacitive loading.
Since the transmission line medium extends onto the printed circuit board, special attention must be
paid to layout and routing of the differential signal pairs.
Designing for 1000 BASE-T GbE operation is very similar to designing for 10 and 100 Mb/s. For the
I210, system level tests should be performed at all three speeds.
12.5.6.1 Guidelines for Component Placement
Component placement can affect signal quality, emissions, and component operating temperature This
section provides guidelines for component placement.
Careful component placement can:
• Decrease potential problems directly related to electromagnetic interference (EMI), which could
cause failure to meet applicable government test specifications.
• Simplify the task of routing traces. To some extent, component orientation will affect the
complexity of trace routing. The overall objective is to minimize turns and crossovers between
traces.
I210
MDI_PLUS (0)
MDI_MINUS (0)
MDI_PLUS (1)
MDI_MINUS (1)
57
58
54
55
MDI_PLUS (2)
MDI_MINUS (2)
MDI_PLUS (3)
MDI_MINUS (3)
52
53
49
50
LAN_1.5V
10/100 Magnetics
Module with Common Mode
Choke in Both Rx and Tx
Paths
50 O hm
Resistors