USB 3.0 Hub Design Guide
© 2015 Genesys Logic, Inc. - All rights reserved. Page 23
GLI Confidential
3.2 Channel Description – with a Cable
Figure 3.2 Channel Model with a Cable
Fig. 3.2 shows the channel topology (with a cable). The insertion loss of 8/7/8 FR4 trace is around 0.296dB
per inch (2.5G signal & PCB trace w/o via). The insertion loss of 34AWG cable is around 4.4dB per meter. So,
the worst case of total insertion loss is around -20dB (It is equal to 9-inch (-2.664dB) + 3m (-13.2dB) + 6-inch
(-1.776dB) + -2dB (-1dB/mated connectors)), and also need to take care about crosstalk (NEXT, FEXT).
Finally, the HUB PCB design must pass compliance channel testing.
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