SARA-R4 series - System Integration Manual
UBX-16029218 - R06
Design-in
Page 62 of 102
Guidelines for single SIM card connection with detection
An application circuit for the connection to a single removable SIM card placed in a SIM card holder is described
in Figure 28, where the optional SIM card detection feature is implemented.
Follow these guidelines connecting the module to a SIM connector implementing 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.
Connect one pin of the normally-open mechanical switch integrated in the SIM connector (as the SW2 pin in
Figure 28) to the
GPIO5
input pin, providing a weak pull-down resistor (e.g. 470 k
, as R2 in Figure 28).
Connect the other pin of the normally-open mechanical switch integrated in the SIM connector (SW1 pin in
Figure 28) to
V_INT
1.8 V supply output by means of a strong pull-up resistor (e.g. 1 k
, as R1 in Figure 28)
Provide a 100 nF bypass capacitor (e.g. Murata GRM155R71C104K) at the SIM supply line (
VSIM
), close to
the related 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
(
VSIM
,
SIM_CLK
,
SIM_IO
,
SIM_RST
), 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 low capacitance (i.e. less than 10 pF) ESD protection (e.g. Tyco Electronics PESD0402-140) on each
externally accessible SIM line, close to each related pad of the SIM connector: ESD sensitivity rating of SIM
interface pins is 1 kV (HBM according to JESD22-A114), so that, according to the EMC/ESD requirements of
the custom application, higher protection level can be required if the lines are externally accessible.
Limit capacitance and series resistance on each SIM signal to match the requirements for the SIM interface
(27.7 ns = max allowed rise time on
SIM_CLK
, 1.0 µs = max allowed rise time on
SIM_IO
and
SIM_RST
).
SARA-R4 series
41
VSIM
39
SIM_IO
38
SIM_CLK
40
SIM_RST
4
V_INT
42
GPIO5
SIM CARD
HOLDER
C
5
C
6
C
7
C
1
C
2
C
3
SIM Card
Bottom View
(contacts side)
C1
VPP (C6)
VCC (C1)
IO (C7)
CLK (C3)
RST (C2)
GND (C5)
C2 C3
C5
J1
C4
SW1
SW2
D1 D2 D3 D4 D5 D6
R2
R1
C
8
C
4
TP
Figure 28: Application circuit for the connection to a single removable SIM card, with SIM detection implemented
Reference
Description
Part Number - Manufacturer
C1, C2, C3, C4
47 pF Capacitor Ceramic C0G 0402 5% 50 V
GRM1555C1H470JA01 - Murata
C5
100 nF Capacitor Ceramic X7R 0402 10% 16 V
GRM155R71C104KA01 - Murata
D1
–
D6
Very Low Capacitance ESD Protection
PESD0402-140 - Tyco Electronics
R1
1 k
Resistor 0402 5% 0.1 W
RC0402JR-071KL - Yageo Phycomp
R2
470 k
Resistor 0402 5% 0.1 W
RC0402JR-07470KL- Yageo Phycomp
J1
SIM Card Holder
6 + 2 positions, with card presence switch
Various Manufacturers,
CCM03-3013LFT R102 - C&K Components
Table 23: Example of components for the connection to a single removable SIM card, with SIM detection implemented