Product Info

LTE Standard Module Series
EC25 Series Hardware Design
EC25_Series_Hardware_Design 51 / 134
EC25 supports (U)SIM card hot-plug via the USIM_PRESENCE pin. The function supports low level and
high level detections. By default, it is disabled, and can be configured via AT+QSIMDET command.
Please refer to document [2] for more details about the command
The following figure shows a reference design for (U)SIM interface with an 8-pin (U)SIM card connector.
Module
USIM_VDD
USIM_GND
USIM_RST
USIM_CLK
USIM_DATA
USIM_PRESENCE
0R
0R
0R
VDD_EXT
51K
(U)SIM Card Connector
GND
GND
VCC
RST
CLK
IO
VPP
GND
GND
USIM_VDD
15K
100 nF
33 pF
33 pF 33 pF
Figure 17: Reference Circuit of (U)SIM Interface with an 8-pin (U)SIM Card Connector
If (U)SIM card detection function is not needed, please keep USIM_PRESENCE unconnected. A
reference circuit for (U)SIM interface with a 6-pin (U)SIM card connector is illustrated in the following
figure.
Module
USIM_VDD
USIM_GND
USIM_RST
USIM_CLK
USIM_DATA
0R
0R
0R
(U)SIM Card Connector
GND
VCC
RST
CLK IO
VPP
GND
GND
15K
USIM_VDD
33 pF 33 pF 33 pF
100 nF
Figure 18: Reference Circuit of (U)SIM Interface with a 6-pin (U)SIM Card Connector
In order to enhance the reliability and availability of the (U)SIM card in customers’ applications, please
follow the criteria below in (U)SIM circuit design: