Nvidia Jetson TX2 Manual page 92

Figure 53. Transmission Line Height
▪
Transmission line return current:
- High-speed return current follow s the path of least inductance.
- The low est inductance path for a transmission line is the portion of the line closest to the dielectric surface;
i(D) is proportional to
1
(
1 +
▪
Crosstalk on solid reference plane (Figure 54):
- Crosstalk is caused by the mutual inductance of tw o parallel traces.
- Crosstalk at the second trace is proportional to
1
(
1 +
- The signals need to be properly spaced to minimize crosstalk.
Figure 54. Crosstalk on Reference Plane
▪
Reference plane selection
- Solid ground is preferred as reference plane.
- Solid pow er can be used as reference plane w ith decoupling capacitors near driver and receiver.
- Reference plane cuts and layer changes need to be avoided.
▪
Pow er plane cut example (Figure 55)
- Pow er plane cuts w ill cause EMI issues.
- Pow er plane cuts also induce crosstalk to adjacent signals.
Figure 55. Example of Power Plane Cuts
▪
When cut is unavoidable:
• Place decoupling capacitors near transition.
-
• Place transition near source or receiver w hen decoupling capacitors are abundant ( Figure 56).
-
JETSON TX2/TX2i OEM PRODUCT | DESIGN GUIDE | 20180618
2
D
)
H
2
D
)
H
NVIDIA Jetson TX2/TX2i OEM Product Design Guide
92