Nvidia Jetson TX2 Manual page 37

Table 30. Ethernet MDI Interface Signal Routing Requirements
Parameter
Reference plane
Trace Impedance Diff pair / Single Ended
Min Trace Spacing (Pair-Pair)
Max Trace Length
Max Within Pair (Intra-Pair) Skew
Number of Vias
Table 31. Ethernet Signal Connections
Module Pin Name Type
GBE_MDI[3:0]+/– DIFF
I/O
GBE_LINK_ACT O
GBE_LINK100 O
GBE_LINK1000 O
GBE_CTREF na
Table 32. Recommended Gigabit Ethernet observation (test) points for initial boards
Test Points Recommended
One for each of the MDI[3:0]+/– lines.
JETSON TX2/TX2i OEM PRODUCT | DESIGN GUIDE | 20180618
Requirement
GND
100 / 50
0.763
109 (690)
0.15 (1)
minimum
Termination
ESD device to GND per signal
681Ω series resistor & 0.1uF capacitor to GND
681Ω series resistor & 0.1uF capacitor to GND.
10kΩ Pull-down to GND (exists on the module)
681Ω series resistor & 0.1uF capacitor to GND
Units Notes
Ω ±15%. Differential impedance target is 100Ω. 90Ω can be used if 100Ω
is not achievable
mm
mm (ps)
mm (ps)
Ideally there should be no vias, but if required for breakout to Ethernet
controller or magnetics, keep very close to either device.
Description
Gigabit Ethernet MDI IF Pairs: Connect to Magnetics +/– pins
Gigabit Ethernet ACT : Connect to LED1C on Ethernet connector.
Gigabit Ethernet Link 100 : Connect to LED2C on Ethernet connector.
Pulldown part of strapping to use 3.3V PHY mode.
Gigabit Ethernet Link 1000 : Connect to Link 1000 LED on conn.
Not used
Location
Near the module connector & Magnetics device.
NVIDIA Jetson TX2/TX2i OEM Product Design Guide
37