Fibocom FM101-GL, Руководство по оборудованию

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3 Application Interface
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
USB_D- and USB_D+ signal lines should have the differential impedance of 90
±
10
ohms.

USB_D- and USB_D+ signal cables must be less than 2mm in length and parallel, the
right angle routing should be avoided.

USB_D- and USB_D+ signal lines should be routed on the layer that is adjacent to the
ground layer, and wrapped with GND vertically and horizontally.
3.5.3 USB3.0 Interface Application
The reference circuit is shown in Figure 15:
AP Module
USB3.0_RX-
USB3.0_RX+
USB3.0_TX-
USB3.0_TX+
USB3.0_TX-
USB3.0_TX+
USB3.0_RX+
USB3.0_RX-
0R
0R
100nF
100nF
Figure 15. Reference circuit for USB 3.0 interface
USB 3.0 signals are super speed differential signal lines with the maximum transfer rate of
5Gbps. So the following rules should be followed carefully in the case of PCB layout:

USB 3.0_TX-/USB 3.0_TX+ and USB 3.0_RX-/ USB 3.0_RX+ are two pairs differential
signal lines. The differential impedance should be controlled as 90
±
10 ohms.

The two pairs differential signal lines should be parallel and have the equal length. The
right angle routing should be avoided.

The two pairs differential signal lines should be routed on the layer that is adjacent to
the ground layer, and wrapped with GND vertically and horizontally.