Intel 820E Manuel D’Utilisation
Intel
®
820E Chipset
R
114
Design
Guide
2.22.3.5. Critical
Dimensions
As shown in the following figure, there are three dimensions to consider during layout: Distance B, from
the line RJ11 connector to the magnetics module; distance C, from the phone RJ11 to the LPF (if
implemented); and distance A, from the Intel
the line RJ11 connector to the magnetics module; distance C, from the phone RJ11 to the LPF (if
implemented); and distance A, from the Intel
82562EH component to the magnetics module.
Figure 71. Critical Dimensions for Component Placement
IO_subsys_crit_dim_comp_plac
ICH2
Intel®
82562EH
Magnetics
module
Line
RJ11
B
A
EEPROM
LPF
Phone
RJ11
C
Distance Priority Guideline
B 1
<1
inch
A 2
<1
inch
C 3
<1
inch
2.22.3.5.1. Distance from Magnetics Module to Line RJ11
Distance B should be given highest priority and should be less then 1 inch. Regarding trace symmetry,
route differential pairs with consistent separation and with exactly the same lengths and physical
dimensions.
route differential pairs with consistent separation and with exactly the same lengths and physical
dimensions.
Asymmetry and unequal length in differential pairs contribute to common-mode noise. This can degrade
the receive-circuit performance and contribute to radiated emissions from the transmit side.
the receive-circuit performance and contribute to radiated emissions from the transmit side.
2.22.3.5.2. Distance from Intel
®
82562EH Component to Magnetics Module
Due to the high speed of signals present, distance ‘A’ between the Intel
82562EH component and the
magnetics also should be less than 1 inch, but it should be second priority relative to the distance from
the connects to the magnetics module.
the connects to the magnetics module.
In general, any trace section intended for use with high-speed signals should comply with the proper
termination practices. Proper signal termination can reduce reflections caused by impedance mismatches
between devices and trace routes. A signal’s reflection may contain a high-frequency component that
may contribute more EMI than the original signal itself.
termination practices. Proper signal termination can reduce reflections caused by impedance mismatches
between devices and trace routes. A signal’s reflection may contain a high-frequency component that
may contribute more EMI than the original signal itself.