Quectel BG95 A-GL Series Hardware Design page 53

To ensure USB data signal integrity, if possible, reserve a 0 Ω resistor on USB_DP and USB_DM traces,
respectively. Resistors R1 and R2 should be placed close to the module and to each other. The extra
trace stubs must be as short as possible.
To meet USB 2.0 specification, comply with the following principles in USB interface designing.
It is important to route the USB signal traces as a differential pair with ground. The impedance of the

USB differential trace is 90 Ω.
Do not route signal traces under crystals, oscillators, magnetic devices, and RF signal traces. It is

important to route the USB differential traces in inner layers of the PCB, and surround the traces with
ground on that layer and with ground planes above and below.
Junction capacitance of the ESD protection components might influence USB data traces, so pay

attention to device selection. Typically, the stray capacitance should be less than 2 pF.
Keep the ESD protection components as close to the USB connector as possible.

If possible, reserve a 0 Ω resistor on USB_DP and USB_DM traces, respectively.

For more details about the USB specifications, visit http://www.usb.org/home.
NOTE
1. After the module is turned off or enters PSM, do not pull up any USB interface pin lest it cause
additional power consumption and potentially damage pins on the module.
2. For more details about using the UMTS&LTE EVB board to test the USB interface function of the
module, see document [7].
BG95xA-GL_Hardware_Design
Figure 25: Reference Circuit of USB Application
LPWA Module Series
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