Product Info

Smart LTE Module Series
SC66 Hardware Design
SC66_Hardware_Design 60 / 118
USIM_ VDD
USIM_ RST
USIM_ CLK
USIM_ DATA
USIM_ DET
22R
100K
100nF
(U)SIM Card Connector
ESD
22pF
VCC
RST
CLK
IO
VPP
GND
USIM_ VDD
10K
Module
R1
R2
C1
22pF22pF
C2 C3 C4
D1
22R
22R
R3
R4
R5
LDO13A_1P8
Figure 17: Reference Circuit for (U)SIM Interface with an 8-pin (U)SIM Card Connector
If there is no need to use USIM_DET, please keep it open. The following is a reference circuit for (U)SIM
interface with a 6-pin (U)SIM card connector.
Module
USIM_ VDD
USIM_ RST
USIM_ CLK
USIM_ DATA
22R
22R
22R
100nF
ESD
22pF
VCC
RST
CLK IO
VPP
GND
10K
USIM_VDD
22pF
22pF
R1
C1
D1
R2
R3
R4
C2 C3 C4
USIM_ DET
(U)SIM Card Connector
Figure 18: 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, please follow the criteria below
in (U)SIM circuit design:
 Keep placement of (U)SIM card connector as close to the module as possible. Keep the trace length
of (U)SIM card signals as less than 200mm as possible.
 Keep (U)SIM card signals away from RF and VBAT traces.
 A filter capacitor shall be reserved for USIM_VDD, and its maximum capacitance should not exceed
1uF. The capacitor should be placed near to (U)SIM card.
 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.