82562EZ_08 Datasheet, PDF (35/66 Pages) Intel Corporation – Dual Footprint

82562EZ(EX)/82547GI(EI) Dual Footprint Design Guide
Figure 8 below shows the preferred method for implementing a ground split under an integrated
magnetics module/RJ-45 connector. The capacitor stuffing options (C1 – C6) are used to reduce/
filter high frequency emissions. The value(s) of the capacitor stuffing options may be different for
each board. Experiments will need to be performed to determine which value(s) provide best EMI
performance.
Board Edge
RJ/Mag.
Chassis
GND
Capacitor
Stuffing
Options
RJ Shield
connected to
Chassis
GND
Capacitor
Stuffing
Options
C1
C2
C3
C4
C5
C6
Digital
GND
Resistive
Terminations
Figure 8. Ideal Ground Split Implementation
The table below gives some starting values for these capacitors.
C3, C4
C1, C2, C5, C6
Capacitors
4.7µF or 10 µF
470 pF to 0.1 µF
Value
The placement of C1 – C6 may also be different for each board design (i.e., not all of the capacitors
may need to be populated). Also, the capacitors may not be needed on both sides of the magnetic
module.
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