Nvidia Jetson TX2 Manual page 29

Common-mode Choke (
Only if needed. Place near connector.
Common-mode impe dance @100MHz
Max Rdc
Differential TDR impedance @T
Min Sdd21 @ 2.5GHz
Max Scc21 @ 2.5GHz
Routing length reduction
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
Connector used must be USB-IF certified
Note: Longer trace lengths may be possible if the total trace loss is equal to or better than the target. If the loss is greater, the
1.
max trace lengths will need to be reduced.
Recommend trace length matching to <1ps before Vias or any discontinuity to minimize common mode conversion.
2.
Place GND Vias as symmetrically as possible to data pair Vias.
3.
Com m on USB Routing Guidelines
Guideline
If routing to USB device or USB connector includes a flex or 2
calculations.
Keep critical USB related traces away from other signal traces or unrelated power traces/areas or power supply components
Table 19. Module USB 2.0 Signal Connections
Module Ball Name Type
USB[2:0]_D+ DIFF
USB[2:0]_D– I/O
Table 20. Miscellaneous USB 2.0 Signal Connections
Module Pin Name Type
USB0_VBUS_DET A
USB0_OTG_ID A
Table 21. USB 3.0 Signal Connections
Module Pin Name
USB_SS0_TX+/– (USB 3.0 Port #0)
PEX_RFU_TX+/– (USB 3.0 Port #1)
USB_SS1_TX+/– (USB 3.0 Port #2)
USB_SS0_RX+/– (USB 3.0 Port #0)
PEX_RFU_RX+/– (USB 3.0 Port #1)
USB_SS1_RX+/– (USB 3.0 Port #2)
Table 22. Recommended USB observation (test) points for initial boards
Test Points Recommended
One for each of the USB 2.0 data lines (D+/-)
One for each of the USB 3.0 output lines used (TXn_+/-)
JETSON TX2/TX2i OEM PRODUCT | DESIGN GUIDE | 20180618
)
Min/Max 65/90
0.3
-200ps (10%-90%) 90
R
2.22
19.2
<= 3
Same as PCB
Strongly recommend being
the same as PCB or better
nd
PCB, the total routing including all PCBs/flexes must be used for the max trace & skew
Termination
90Ω common-mode chokes close to
connector. ESD Protection between choke
& connector on each line to GND
Termination
100kΩ resistor to GND. See reference
design for VBUS power filtering.
Type Termination
DIFF Series 0.1uF caps. Common-mode chokes &
Out ESD protection if these are used.
DIFF If routed directly to a peripheral on the board,
In AC caps are needed for the peripheral TX lines.
Common-mode chokes & ESD protection, if
these are used.
Location
Near the module connector & USB device. USB connector pins can serve as test points.
Near USB device. USB connector pins can serve as test points
NVIDIA Jetson TX2/TX2i OEM Product Design Guide
Ω
TDK ACM2012D-900-2P
Ω
Ω
dB
dB
in
If worse than PCB, the PCB & FPC length must be re-
estimated
Description
USB Differential Data Pair: Connect to USB connector, Mini-Card
Socket, Hub or other device on the PCB.
Description
USB0 VBus Detect: Connect to VBUS pin of USB connector receiving
USB0_+/– interface. Also connects to VBUS power supply if host mode
supported.
USB Identification: Connect to ID pin of USB OTG connector receiving
USB0_P/M interface.
Description
USB 3.0 Differential Transmit Data Pairs: Connect
to USB 3.0 connectors, hubs or other devices on the
PCB.
USB 3.0 Differential Receive Data Pairs: Connect
to USB 3.0 connectors, hubs or other devices on the
PCB.
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