Intel 820E Benutzerhandbuch

114  

Design 

Guide 

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

 

82562EH component to the magnetics module. 

 

 

IO_subsys_crit_dim_comp_plac

ICH2

 

Intel®

82562EH

 

Magnetics

 

module

 

Line

 

RJ11

 

B

A

EEPROM

 

LPF

 

Phone

 

RJ11

 

C

 

 

 

B 1 

<1 

inch 

A 2 

<1 

inch 

C 3 

<1 

inch 

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. 

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. 

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. 

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.