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4.1.6. (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. Keep the trace length less than
200 mm.
⚫
Keep (U)SIM card signals away from RF and VCC traces.
⚫
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 diode 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
33 pF capacitors are used to filter out RF interference.
⚫
For USIM_DATA, a 10–20 kΩ pull-up resistor must be added near the (U)SIM card connector.
4.2. USB Interface
RM502Q-GL provides one integrated Universal Serial Bus (USB) interface which complies with the USB
3.1/2.0 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 and voice over
USB.
Please note that only USB 2.0 can be used for firmware upgrade currently.
The following table shows the pin definition of USB interface.
Table 15: Pin Definition of USB Interface
Pin No.
Pin Name
7
USB_DP
9
USB_DM
29
USB_SS_TX_M
31
USB_SS_TX_P
35
USB_SS_RX_M
RM502Q-GL_Hardware_Design
I/O
Description
AIO
USB 2.0 differential data bus (+)
AIO
USB 2.0 differential data bus (-)
AO
USB 3.1 super-speed transmit (-)
AO
USB 3.1 super-speed transmit (+)
AI
USB 3.1 super-speed receive (-)
5G Module Series
RM502Q-GL Hardware Design
Comment
Requires differential
impedance of 90 Ω
40 / 83
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