Common Usb Routing Guidelines - Nvidia Jetson AGX Xavier Series Design Manual

Parameter
Value: Min/Max
Location (max length to adjacent discontinuity)
Voiding
ESD
Max Junction capacitance (IO to GND)
Footprint
Location (max length to adjacent discontinuity)
Common-Mode Choke
Common-mode impedance @ 100MHz
Max Rdc
Differential TDR impedance
Min Sdd21 @ 2.5GHz
Max Scc21 @ 2.5GHz
Location
FPC (Additional length of Flexible Printed Circuit Board)
The FPC routing should be included for PCB trace calculations (max length, etc.)
Characteristic Impedance
Loss characteristic
Connector
SMT Connector GND Voiding
Connector type
Notes:
1. Up to 4 signal Vias can share a single GND return Via
2. Recommend trace length matching to <1ps before Vias or any discontinuity to minimize common mode
conversion.
3. Place GND Vias as symmetrically as possible to data pair Vias.
7.1.3

Common USB Routing Guidelines

If routing to USB device or USB connector includes a flex or 2nd PCB, the total routing
including all PCBs and flexes must be used for the max trace and skew calculations.
Keep critical USB related traces away from other signal traces or unrelated power traces and
areas or power supply components.
Jetson AGX Xavier Series Product
Requirement
0.075 / 0.2 uF
8 mm
GND/PWR void under/above cap
is preferred
0.8 pF
Pad should be on the net – not
trace stub
8 mm
Min/Max 65/90 Ω
0.3 Ω
90 Ω @TR-200ps
(10%-90%)
2.22 dB
19.2 dB
8 mm
Same as PCB
Strongly recommend to be same
as PCB or better
Units
Only required for TX pair when routed to
connector
Discontinuity is connector, via, or component
pad
Voiding is required if AC cap size is 0603 or
larger
e.g. SEMTECH RClamp0524p
Discontinuity is connector, via, or component
pad
TDK ACM2012D-900-2P
If worse than PCB, the PCB and FPC length
must be re-estimated
GND plane under signal pad should be voided.
Size of void should be the same size as the
pad.
Connector used must be USB-IF certified
DG-09840-001_v2.5 | 46
USB, PCIe, and UFS
Notes