Smart Machine Smart Decision
SIM800L(MT6261)_Hardware Design_V1.01 37 2016-07-07
Module
SIM Card
VCC
GND
RST
VPP
CLK
I/O
C707 10M 006 512 2
22pF
100nF
SIM_VDD
SIM_RST
SIM_CLK
SIM_DATA
SIM_DET
ESDA6V1
51Ω
51Ω
51Ω
Figure 33: Reference circuit of the 6-pin SIM card holder
4.8.2. SIM Card Design Guide
SIM card signal could be interferenced by some high frequency signal, it is strongly recommended to follow
these guidelines while designing:
SIM card holder should be far away from GSM antenna
SIM traces should keep away from RF lines, VBAT and high-speed signal lines
The traces should be as short as possible
Keep SIM card holder’s GND connect to main ground directly
Shielding the SIM card signal by ground well
Recommended to place a 100nF capacitor on SIM_VDD line and keep close to the SIM card holder
Add some TVS which parasitic capacitance should not exceed 50pF
Add 51Ω resistor to (SIM_RST/SIM_CLK/SIM_DATA) signal could enhance ESD protection
4.8.3. Design Considerations for SIM Card Holder
For 8 pins SIM card holder, SIMCom recommends to use Molex 91228.Customer can visit
http://www.molex.com for more information about the holder.
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