USB 3.0 Hub Design Guide
© 2015 Genesys Logic, Inc. - All rights reserved.
Page 11
GLI Confidential
2.3.7
Differential Pair Layout
The routing of a differential pair must be kept as
same length
,
same width
,
same layer
and
fixed space gap
,
and also be kept as
symmetric
as possible. (as shown in
Fig. 2.7
)
Bad Layout:
Non-symmetric
Preferred Layout:
symmetric routing
Figure 2.7
When vias are used, they should always be placed in same location and symmetric. (as shown in
Fig. 2.8
)
Bot layer
differential pair
Via
Top layer
differential pair
Perferred example
Via placement is symmertic and in same location
Bad example
Via placement is not symmertic / in same location
Figure 2.8