Termination Plane; Termination Plane Capacitance; Light Emitting Diodes For Designs Based On 82562Gz(Gx) Plc; Termination Resistors Placement (Integrated Magnetics Solution) - Intel 82541PI Design Manual

Figure 13. Termination Resistors Placement (Integrated Magnetics Solution)
4.5.1

Termination Plane

Resistors are used to terminate noise from the unused inputs of both the RJ45 connector and the
magnetics module to the termination plane. The netname "termplane" is provided as a guide to the
termination plane. A termplane is a plane fabricated into the PCB substrate. This plane, which has
no DC termination, acts like one-half of a capacitor that provides a path for the coupled noise.
4.5.2

Termination Plane Capacitance

It is recommended that the termination plane capacitance equal a minimum value of 1500 pF. This
helps reduce the amount of crosstalk on the differential pairs (TDP and TDN and RDP and RDN)
from the unused pairs of the RJ45. Pads may be placed for additional capacitance, which may be
required if failure occurs during electrical fast transient testing.
Note: This capacitor must be designed to tolerate 2 KV voltage injections to meet International Special
Committee on Radio Interference (CISPR) Electrostatic Discharge (ESD) specifications.
4.6 Light Emitting Diodes for Designs Based on 82562GZ(GX)
PLC
The 82562GZ(GX) PLC device has three high-current outputs to directly drive LEDs for link,
activity and speed indication. Since LEDs are likely to be integral to a magnetics module, take care
to route the LED traces away from potential sources of EMI noise. In some cases, it may be
desirable to attach filter capacitors.
Application Note (AP-468)
82541PI(ER) and 82562GZ(GX) Dual Footprint LOM Design Guide
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