Gb Ethernet Trace Length Guidelines; Table 20: Ethernet Trace Length Guidelines; Figure 17: Topology For Ethernet Jack - Advantech SOM-5992 Design Manual

2.6.4 Gb Ethernet Trace Length Guidelines

Figure 17 : Topology for Ethernet Jack
Table 20 : Ethernet Trace Length Guidelines
Parameter
Signal Group
Differential Impedance Target
Single End
Spacing between RX and TX
pairs (inter-pair) (s)
Spacing between differential pairs
and high-speed periodic signals
Spacing between differential pairs
and low-speed non periodic
signals
Spacing between digital ground
and analog ground plane
(between the magnetics Module
and RJ45 connector)
LA
LB
Max length of LA+LB
Length matching
Reference Plane
Spacing from edge of plane
Carrier Board Via Usage
Notes:
Main Route Guidelines
GBE0_MDIx+, GBE0_MDIx-
100 Ω ±10%
55Ω ±10%
Min. 50mils
Min. 300mils
Min. 100mils
Min. 60mils
Please see the SOM-5992 Layout Checklist
Carrier Board Length;
COM Express Module to the magnetics Module - 5.0
inches.
Magnetics Module to RJ45 connector - Max. 1.0 inches.
Differential pairs (intra-pair): Max.
GND referencing preferred..
Min. 40mils
Max. 2 vias.
６５
±2.5 mils
Notes