Data Sheet
Ethernet Controller I210 —Design Considerations
814
12.5 Ethernet Interface
12.5.1 Magnetics for 1000 BASE-T
Magnetics for the I210 can be either integrated or discrete.
The magnetics module has a critical effect on overall IEEE and emissions conformance. The device
should meet the performance required for a design with reasonable margin to allow for manufacturing
variation. Occasionally, components that meet basic specifications can cause the system to fail IEEE
testing because of interactions with other components or the printed circuit board itself. Carefully
qualifying new magnetics modules prevents this problem.
When using discrete magnetics it is necessary to use Bob Smith termination: Use four 75 resistors for
cable-side center taps and unused pins. This method terminates pair-to-pair common mode impedance
of the CAT5 cable.
Use an EFT capacitor attached to the termination plane. Suggested values are 1500 pF/2 KV or 1000
pF/3 KV. A minimum of 50-mil spacing from capacitor to traces and components should be maintained.
12.5.2 Magnetics Module Qualification Steps
The steps involved in magnetics module qualification are similar to those for crystal qualification:
1. Verify that the vendor’s published specifications in the component datasheet meet or exceed the
specifications in Section 11.6.
2. Independently measure the component’s electrical parameters on the test bench, checking samples
from multiple lots. Check that the measured behavior is consistent from sample to sample and that
measurements meet the published specifications.
3. Perform physical layer conformance testing and EMC (FCC and EN) testing in real systems. Vary
temperature and voltage while performing system level tests.
12.5.3 Third-Party Magnetics Manufacturers
The following magnetics modules have been used successfully in previous designs.
Manufacturer Type Part Number
Amphenol ICM RJMG2310228A0NRAO3-R
Bel Discrete S588-5999-P3
E&E LP discrete 824-00400R
Foxconn ICM JFM38U1C-L1U1W
Midcom Discrete 7093-37R-LF1
Pulse LP discrete H5019DNL
Tyco ICM 1368398-2
Pulse Standard discrete H5007NL