Quectel SG560D Series - Page 63

Smart Module Series
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The following figure shows a reference design for (U)SIM interface with an 8-pin (U)SIM card connector.
USIM_VDD
USIM_RST
USIM_CLK
USIM_ DATA
USIM_DET
22 R
100 nF
(U)SIM Card Connector
TVS
array
22 pF
VCC
RST
CLK
IO
VPP
GND
Module
C1
22 pF22 pF
C2 C3 C4
D1
22 R
22 R
R1
R2
R3
20KR4
GND
100K
R5
LDO18B_1V8
Figure 15: Reference Circuit of (U)SIM Interface with 8-Pin (U)SIM Card Connector
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
USIM_VDD
USIM_RST
USIM_CLK
USIM_ DATA
22 R
22 R
22 R
100 nF
TVS
array
22 pF
VCC
RST
CLK IO
VPP
GND
22 pF
22 pF
C1
D1
R2
R3
R4
C2 C3 C4
USIM_DET
(U)SIM Card Connector
20K
R1
GND
Figure 16: Reference Circuit of (U)SIM Interface with 6-Pin (U)SIM Card Connector
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 as less
than 200 mm as possible.
⚫ Keep (U)SIM card signals away from RF and VBAT traces.
⚫ To avoid cross-talk between USIM_DATA and USIM_CLK, keep them away from each other and
shield them with surrounded ground. In addition, USIM_RST also needs to be shielded with
surrounded ground.