GD82559C Datasheet, PDF (20/60 Pages) Intel Corporation – Intel-Based Electronic Classroom Student Computing Station Based on the Intel® Celeron™ Processor and Intel® 810 Chipset

Intel-Based Electronic Classroom Student Computing Station
Figure 4. Placement of Termination Resistor
R
82559
R
Magnetics
Module
RJ-45
Place termination resistors
as close to the 82559 as possible.
A7495-01
Figure 5.
The key factors in controlling trace EMI radiation are the trace length and the ratio of trace-width
to trace-height above the ground plane. To minimize trace inductance, high-speed signals, such as
the clock, and signal layers that are close to a ground plane or power plane should be as short and
as wide as is practical. As shown in Figure 5, this ratio is ideally somewhere between 1:1 and 3:1.
To maintain the impedance of a trace, the width of the trace should be modified when changing
from one board layer to another if the two layers are not equidistant from a power or ground plane.
Trace Geometry
W
H
NOTE: W= Trace Width, H= Height Above Ground Plane
Ground
1<W <3
H
A7496-01
20
Application Note