Neo_M680 GPRS Module Hardware User Guide
Copyright © Neoway Technology Co., Ltd
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SIM_CLK can work at several frequencies at 3.25 MHz typically.
Figure 3-18
Reference design of SIM card interface
ESD protectors, such as ESD diodes (lower than 33 pF) or ESD varistors, are recommended on the SIM
signals, especially in automotive electronics or other applications with badly ESD. In other applications,
replace ESD diodes with 27 pF to 33 pF grounding capacitors. The ESD diodes or small capacitors should
be close to SIM card.
If you use 6-pin SIM card sockets, MCP-C713(H2.8) is recommended. Figure 3-19 shows its
encapsulation.
Figure 3-19
Reference of SIM card socket
20
20
20
1 uF
SIM_DATA
SIM_CLK
SIM_RST
VSIM
GPRS
Module
CLK
RST
VCC
VPP
GND
SIM
卡
DATA
