Quectel BG77 - Page 40

LPWA Module Series
BG77 Hardware Design
BG77_Hardware_Design 36 / 76
BG77 supports (U)SIM card hot-plug via USIM_DET. The function supports low level or high level
detections, and is disabled by default. Please refer to document [2] about AT+QSIMDET command for
details.
The following figure shows a reference design of (U)SIM interface with an 8-pin (U)SIM card connector.
Module
USIM_VDD
USIM_GND
USIM_RST
USIM_CLK
USIM_DATA
USIM_DET
0R
0R
0R
VDD_EXT
51K
100nF (U)SIM Card Connector
GND
GND
33pF 33pF 33pF
VCC
RST
CLK
IO
VPP
GND
GND
USIM_VDD
15K
Figure 13: 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_DET 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
(U)SIM Card Connector
GND
33pF 33pF 33pF
VCC
RST
CLK IO
VPP
GND
GND
15K
USIM_VDD
Figure 14: 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 applications, please follow the