IEI Integration ICE-DB-9S - Manual (Page 86)

Page 73
ICE Module
4.11.4 LAN Routing Guideline
4.11.4.1 Impedance
Table 4-21: LAN Impedance Consideration
Parameters Routing
Transfer Rate 1.0 Gbits/sec
Maximum signal line length (coupled traces) 8.0 inches specified by COM Express "
Signal length used on COM Express module
(including the carrier board connector) "
3.0 inches specified by COM Express "
Signal length allowance for the COM Express
carrier board "
5.0 inches to the magnetics module
Maximum signal length between isolation
magnetics module and RJ-45 connector on the
carrier board
1.0 inch
Differential Impedance 95 Ohms +/-20%
Single-ended Impedance 55 Ohms +/-15%
Spacing between RX and TX pairs (inter-pair) (s) Min. 50mils
Spacing between differential pairs and high-speed
periodic signals
Min. 300mils
Spacing between differential pairs and low-speed
non periodic signals
Min. 100mils
Length matching between differential pairs
(intra-pair)
Max. 5mils
Length matching between RX and TX pairs
(inter-pair)
Max. 30mils
Spacing between digital ground and analog ground
plane (between the magnetics module and RJ-45
connector)
Min. 60mils
Spacing from edge of plane Min. 40mils
Via Usage
Max. of 2 vias on TX path Max. of 2
vias on RX path