Usb Interface - Quectel LPWA Series Hardware Design

To enhance the reliability and availability of the (U)SIM card in applications, please follow the criteria
below in the (U)SIM circuit design:
Keep the placement of (U)SIM card connector as close to the module as possible.

Keep the trace length as less than 200 mm as possible.

Keep (U)SIM card signals away from RF and VBAT traces.

Assure the ground between the module and the (U)SIM card connector short and wide. Keep the

trace width of ground and USIM_VDD no less than 0.5 mm to maintain the same electric potential. If
the ground is complete on customers' PCB, USIM_GND can be connected to PCB ground directly.
Make sure the bypass capacitor between USIM_VDD and USIM_GND less than 1 μF, and place it

as close to (U)SIM card connector as possible.
To avoid cross-talk between USIM_DATA and USIM_CLK, keep them away from each other and

shield them with surrounded ground.
To offer good ESD protection, it is recommended to add a TVS diode array of which parasitic

capacitance should not be more than 15 pF. The 0 Ω resistors should be added in series between
the module and the (U)SIM card to facilitate debugging. The 33 pF capacitors are used for filtering
interference of EGSM900. Please note that the (U)SIM peripheral circuit should be close to the
(U)SIM card connector.
The pull-up resistor on USIM_DATA trace can improve anti-jamming capability when long layout

trace and sensitive occasions are applied, and should be placed close to the (U)SIM card
connector.
4.2. USB Interface*
The module provides one USB interface. The USB interface complies with the USB 2.0 specifications,
and supports Full-speed (12 Mbps) and Low-speed (1.5 Mbps) for USB 2.0.
USB interface is used AT command communication, data transmission, software debugging and firmware
upgrade.
Table 13: Pin Definition of USB Interface
Pin Name Pin No.
USB_VBUS 8
USB_DP 9
USB_DM 10
BG950A-GL&BG951A-GL_Hardware_Design
I/O Description
AI USB connection detect
AIO USB differential data (+)
AIO USB differential data (-)
LPWA Module Series
Comment
Typ. 5.0 V
Compliant with USB 2.0
standard specification. Require
differential impedance of 90 Ω.
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