Reference Schematic; Layout Consideration; Figure 13 Usb Ports Reference Schematic - Emerson COM Express Carrier Design Manual

6.2 Reference Schematic

Figure 12 USB Ports Reference Schematic

6.3 Layout Consideration

Route USB signals as differential pairs, with a 90 ohm differential impedance and a 45 ohm, single-
ended impedance. Ideally, a USB pair is routed on a single layer adjacent to a ground plane. USB pairs
should not cross plane splits. Keep layer transitions to a minimum. Reference USB pairs to a power
plane if necessary. The power plane should be well-bypassed. Section 21.3.2 USB Trace Routing
Guidelines summarizes the USB routing rules.
Page 40 of 103 COM Express Carrier Type 2
Design Guide