5G Module Series
RM502Q-GL Hardware Design
RM502Q-GL_Hardware_Design 32 / 77
If (U)SIM card detection function is not needed, please keep USIM_DET unconnected. A reference circuit
for (U)SIM card interface with a 6-pin (U)SIM card connector is illustrated in the following figure.
Module
(U)SIM Card
Connector
USIM1_DET
USIM1_DATA
USIM1_CLK
RST
CLK
IO
USIM1_VDD
USIM1_VDD
USIM1_RST
VCC
GND
VPP
GND
TVS
Note:
All these resistors, capacitors and TVS should be close to (U)SIM card connector in PCB layout.
36
30
32
66
34
10-20k
22R
22R
22R
3
3
p
F
3
3
p
F
3
3
p
F
100 nF
Figure 19: Reference Circuit of a 6-Pin (U)SIM Card Connector
In order to enhance the reliability and availability of the (U)SIM card in applications, please follow the
criteria below in (U)SIM circuit design.
⚫
Keep (U)SIM card connector as close as possible to the module. Keep the trace length as less than
200 mm as possible.
⚫
Keep (U)SIM card signal traces 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 ground surrounded.
⚫
In order to offer good ESD protection, it is recommended to add a TVS diode array with parasitic
capacitance not exceeding 10 pF. The 22
Ω resistors should be added in series between the module
and the (U)SIM card connector so as to suppress EMI spurious transmission and enhance ESD
protection. The 33 pF capacitors are used to filter out RF interference.
⚫
The pull-up resistor on USIM_DATA trace improves anti-jamming capability and should be placed
close to the (U)SIM card connector.
3.7. 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) 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*.