LTE-A Module Series
EM121R-GL Hardware Design
EM121R-GL Hardware Design 38 / 80
4.1.5. (U)SIM Card Connector Without Hot-plug
If the (U)SIM card detection function is not needed, please keep USIM_DET unconnected. A reference
circuit for the (U)SIM card interface with a 6-pin (U)SIM card connector is illustrated by the following
figure.
Module
(U)SIM Card
Connector
USIM_DET
USIM_DATA
USIM_CLK
RST
CLK
IO
USIM_VDD
USIM_VDD
USIM_RST
VCC
GND
VPP
GND
ESD
Note:
All these resistors, capacitors and TVS should be close to (U)SIM card connector in PCB layout.
10-20k
22R
22R
22R
3
3
p
F
3
3
p
F
3
3
p
F
100 nF
Figure 16: Reference Circuit for a 6-Pin (U)SIM Card Connector
4.1.6. (U)SIM2 Card Connector
EM121R-GL provides two (U)SIM interfaces. (U)SIM1 interface is used for external (U)SIM card only, and
(U)SIM2 interface is used for external (U)SIM card or internal eSIM card.
It should be noted that, when the (U)SIM2 interface is used for an external (U)SIM card, the circuits are
the same as those of (U)SIM1 interface. When the (U)SIM2 interface is used for the internal eSIM card,
pins 40, 42, 44, 46 and 48 of the modules must be kept open.
A recommended compatible design for the (U)SIM2 interface is shown below.
Module
(U)SIM Card
Connector
USIM2_DET
USIM2_DATA
USIM2_CLK
RST
CLK
CD
IO
USIM2_VDD
USIM2_VDD
USIM2_RST
VCC
GND
VPP
GND
ESD
Note:
The five 0
Ω resistors must be close to M.2 socket connector, and all other components should be close
to (U)SIM card connector in PCB layout.
48
46
44
40
42
10-20K
22
Ω
22
Ω
22
Ω
3
3
p
F
3
3
p
F
3
3
p
F
100 nF
0
Ω
0
Ω
0
Ω
0
Ω
0
Ω
eSIM
Figure 17: Recommended Compatible Design for (U)SIM2 Interface