SARA-R4 series - System integration manual
UBX-16029218 - R20 Design-in Page 79 of 128
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2.5.1.2 Guidelines for single SIM card connection without detection
A removable SIM card placed in a SIM card holder must be connected to the SIM card interface of
SARA-R4 series modules as described in Figure 48, where the optional SIM detection feature is not
implemented.
Follow these guidelines to connect the module to a SIM connector without SIM presence detection:
• Connect the UICC / SIM contacts C1 (VCC) to the VSIM pin of the module.
• Connect the UICC / SIM contact C7 (I/O) to the SIM_IO pin of the module.
• Connect the UICC / SIM contact C3 (CLK) to the SIM_CLK pin of the module.
• Connect the UICC / SIM contact C2 (RST) to the SIM_RST pin of the module.
• Connect the UICC / SIM contact C5 (GND) to ground.
• Provide a 100 nF bypass capacitor (e.g. Murata GRM155R71C104K) on SIM supply line, close to
the relative pad of the SIM connector, to prevent digital noise.
• Provide a bypass capacitor of about 22 pF to 47 pF (e.g. Murata GRM1555C1H470J) on each SIM
line, very close to each related pad of the SIM connector, to prevent RF coupling especially in case
the RF antenna is placed closer than 10 - 30 cm from the SIM card holder.
• Provide a very low capacitance (i.e. less than 10 pF) ESD protection (e.g. Tyco PESD0402-140) on
each externally accessible SIM line, close to each relative pad of the SIM connector. ESD sensitivity
rating of the SIM interface pins is 1 kV (HBM). So that, according to EMC/ESD requirements of the
custom application, higher protection level can be required if the lines are externally accessible on
the application device.
• Limit capacitance and series resistance on each SIM signal to match the SIM requirements (18.7
ns is the maximum allowed rise time on clock line, 1.0 µs is the maximum allowed rise time on data
and reset lines).
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