USB 3.0 Hub Design Guide
© 2015 Genesys Logic, Inc. - All rights reserved.
Page 8
GLI Confidential
2.3.4
Trace Bend
When traces are encountered, please
use 45
bends
(or turns) of traces. The inner air gap of a bend,
A
should
be
≧
20 mils
and the angles between traces should be greater than
135 degrees. (
135
)
and the length of
B
and
C
should be
minimized
.
Pad
Pad
A
C
B
α
Figure 2.2
2.3.5
Reference Plane
Make sure that the differential trace layer and adjacent layer are with solid GND plane.
The differential pair trace must be
kept in the outer layer
, and have a
continual full ground plane
at
neighbor
layer
for reference. (See
Fig. 2.3)
Figure 2.3
Top Layer
USB HUB Controller
Full Ground Layer (Better)
SS Traces on Top Layer
Power or Ground Layer
USB Connector
Bottom Layer