Smart Module Series
SC606T Series Hardware Design
SC606T_Series_Hardware_Design 49 / 116
an 8-pin (U)SIM card connector is shown below.
USIM_ VDD
USIM_ RST
USIM_ CLK
USIM_ DATA
USIM_ DET
22R
LD05_1P8
100K
100 nF
(U)SIM Card Connector
ESD
22 pF
VCC
RST
CLK
IO
VPP
GND
USIM_ VDD
10K
Module
R1
R2
C1
22 pF
22 pF
C2
C3
C4
D1
22R
22R
R3
R4
R5
Figure 15: Reference Design for (U)SIM Interface with an 8-pin (U)SIM Card Connector
If there is no need to use USIM_DET, keep it open. The following is a reference design for the (U)SIM
interfaces connected with a 6-pin (U)SIM card connector.
Module
USIM_ VDD
USIM_ RST
USIM_ CLK
USIM_ DATA
22R
22R
22R
100 nF
ESD
22 pF
VCC
RST
CLK
IO
VPP
GND
10K
USIM _VDD
22 pF
22 pF
R1
C1
D1
R2
R3
R4
C2
C3
C4
USIM_ DET
(U)SIM Card Connector
Figure 16: Reference Design for (U)SIM Interface with a 6-pin (U)SIM Card Connector
To ensure good performance and avoid damage of (U)SIM cards, please follow these principles in your
design:
⚫
Place the (U)SIM card connector as close to the module as possible. Keep the (U)SIM trace length
as less than 200 mm as possible.
⚫
Keep (U)SIM card signal traces away from RF and VBAT traces.
⚫
Reserve a filter capacitor for USIM_VDD, and keep the capacitance of the capacitor within 1
μF.
Place the capacitor near to the (U)SIM card.
⚫
To avoid cross-talk between USIM_DATA and USIM_CLK traces, keep them away from each other
and shield them with the ground. USIM_RST also needs such ground protection.
⚫
To offer good ESD protection, add a TVS diode array with a parasitic capacitance within 50 pF. The
22
Ω resistors should be added in series between the module and (U)SIM card so as to suppress