Intel 82547EI, Руководство по конструкции

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82562EZ(EX)/82547GI(EI) Dual Footprint Design Guide
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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.
Figure 8. Ideal Ground Split Implementation
The table below gives some starting values for these capacitors.
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.
Board Edge RJ/Mag.
Chassis
GND
RJ Shield
connected to
Chassis
GND
Capacitor
Stuffing
Options
Capacitor
Stuffing
Options
Resistive
Terminations
Digital
GND
C1 C2 C3
C4 C5 C6
Capacitors Value
C3, C4 4.7
µ
F or 10
µ
F
C1, C2, C5, C6 470 pF to 0.1
µ
F