Quectel EG21-G - Page 40

LTE Module Series
EG21-G Hardware Design
EG21-G_Hardware_Design 39 / 100
and high level detections, and is disabled by default. Please refer to document [2] for more details about
AT+QSIMDET 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
100nF
GND
GND
33pF
33pF 33pF
VCC
RST
CLK
IO
VPP
GND
GND
USIM_VDD
15K
(U)SIM Card Connector
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
100nF
GND
33pF 33pF 33pF
VCC
RST
CLK IO
VPP
GND
GND
15K
USIM_VDD
(U)SIM Card Connector
Figure 18: Reference Circuit of (U)SIM Interface with a 6-Pin (U)SIM Card Connector