5G Module Series
RM520N-GL_Hardware_Design 44 / 84
4.1.7. (U)SIM Design Notices
To enhance the reliability and availability of the (U)SIM card in applications, please follow the criteria
below in (U)SIM circuit design.
⚫ Place the (U)SIM card connector as close to the module as possible, (U)SIM card related resistance
and capacitance and ESD devices should be placed close to the card connector. Keep the trace
length less than 200 mm.
⚫ Keep (U)SIM card signals away from RF and VCC traces.
⚫ Ensure the ground between the module and the (U)SIM card connector is short and wide. Keep the
trace width of ground and USIM_VDD no less than 0.5 mm to maintain the same electric potential.
⚫ To avoid cross-talk between USIM_DATA and USIM_CLK, keep them away from each other and
shield them with surrounded ground.
⚫ To offer better ESD protection, add a TVS array of which the parasitic capacitance should be not
higher than 10 pF. Add 22 Ω resistors in series between the module and the (U)SIM card connector
to suppress EMI such as spurious transmission, and to enhance ESD protection. The 10 pF
capacitors are used to filter out RF interference.
⚫ For USIM1_DATA, a 10–20 kΩ pull-up resistor must be added near the (U)SIM card connector.
4.2. USB Interface
The module provides one integrated Universal Serial Bus (USB) interface which complies with the USB
3.1 Gen2 & USB 2.0 specifications and supports super speed (10 Gbps) on USB 3.1 and high speed
(480 Mbps) and full speed (12 Mbps) modes on USB 2.0. The USB interface is used for AT command
communication, data transmission, GNSS NMEA sentence output, software debugging, firmware
upgrade (USB 2.0 only) and voice over USB*.
Please note that only USB 2.0 can be used for firmware upgrade currently.
Table 15: Pin Definition of USB Interface
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