Quectel SC200R Series Hardware Design page 54

If you do not need to use USIM_DET, keep this pin open. The following is a reference circuit for (U)SIM
interface with a 6-pin (U)SIM card connector.
USIM_VDD
USIM_RST
USIM_CLK
Module
USIM_DATA
Figure 16: Reference Circuit for (U)SIM Interface with a 6-pin (U)SIM Card Connector
In order to ensure good performance and avoid damage of (U)SIM cards, follow the criteria listed below
during (U)SIM circuit design:
⚫
Place the (U)SIM card connector as close to the module as possible. Keep the trace length of (U)SIM
card signals as less than 200 mm as possible.
⚫
Keep (U)SIM card signals away from RF and VBAT traces.
⚫ Reserve a filter capacitor for USIM_VDD, and its maximum capacitance should not exceed 1 μF.
Additionally, place the capacitor near the
⚫
To avoid cross-talk between USIM_DATA and USIM_CLK, keep them away from each other and
shield them with ground. USIM_RST also needs ground protection.
⚫
In order to ensure good ESD protection, it is recommended to add a TVS diode array with parasitic
capacitance not exceeding 50 pF. Add 22 Ω resistors in series between the module and (U)SIM card
to suppress EMI spurious transmission and enhance ESD protection. Please note that the (U)SIM
peripheral circuit should be close to the (U)SIM card connector.
⚫
Add 22 pF capacitors in parallel on USIM_DATA, USIM_CLK and USIM_RST signal lines to filter RF
interference, and place them as close to the
⚫
Place the reserved pull-up resistors R6 and R5 in Figure 16 and 17 close to the module.
SC200R&SC262R_Series_Hardware_Design
USIM_ VDD USIM_VDD
R5
R1
10K
NM
22R
R2
R3
22R
22R
R4
C2
22 pF 22 pF
(U)SIM
(U)SIM
C1
(U)SIM card connector
100 nF
D1
C3 C4
22 pF
ESD
card connector.
card connector as possible.
Smart Module Series
VCC GND
RST VPP
CLK IO
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