Sunsea AIoT SIMCom SIM7600NA, User Manual, Page: 38 / 74

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SIM7600NA_user manual _V1.00 38 2020-1-7
SIM card circuit is susceptible, the interference may cause the SIM card failures or some other
situations, so it is strongly recommended to follow these guidelines while designing:
 Make sure that the SIM card holder should be far away from the antenna while in PCB
layout.
 SIM traces should keep away from RF lines, VBAT and high-speed signal lines.
 The traces should be as short as possible.
 Keep SIM holder’s GND connect to main ground directly.
 Shielding the SIM card signal by ground.
 Recommended to place a 0.1 ～ 1uF capacitor on USIM_VDD line and keep close to the
holder.
 The rise/fall time of USIM_CLK should not be more than 40ns.
 Add some TVS and the parasitic capacitance should not exceed 60pF.