Usb Interface; Usb_Dm & Usb_Dp Signals - Quectel EC2 Series Design Manualline

3.3. USB Interface

3.3.1. USB_DM & USB_DP Signals

The spacing between USB_DP/USB_DM and other signal traces should be greater than 0.5 mm,
maintaining the integrity of the reference plane and avoiding crossing with signal lines on adjacent
layers.

USB_DP and USB_DM are recommended to be routed on the inner layer, with the differential
impedance controlled to 90 Ω. Keep the spacing and length between traces comparatively equal,
with the length tolerance less than 2 mm and the total length less than 120 mm.

When a TVS needs to be added for USB_DP and USB_DM signal traces, it should be close to USB
connector and the junction capacitance of the TVS should be less than 2 pF.
USB_DM/
USB_DM/
DP
DP
Test
Test
points
points
USB
USB
connector
connector
Figure 10: Overview of USB_DM/DP Signal Traces (EVB 1st Layer)
EC2x&EG2x-G_Series_PCB_Design_Guideline
EC2x&EG2x-G Series PCB Design Guideline
GND
GND
GND
GND
LTE Standard Module Series
TE-A
TE-A
interface
interface
GND
GND
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