Users Manual
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Power traces must consider not only VBAT, but also the return GND of the power supply. The trace of the positive
electrode of VBAT must be short. To be thick, the trace must first pass through the large capacitor, Zener diode and
then the power PIN of the module. There are multiple PAD exposed copper at the bottom of the module. It is
necessary to ensure that the GND path of these exposed copper areas to the power supply is the shortest and most
smooth. This ensures that the current path of the entire power supply is the shortest and the interference is minimal.
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The size of the SIM card is large, and there is no anti-EMI interference device itself, which is relatively susceptible to
interference. Therefore, in the layout, first ensure that the SIM card is away from the antenna and the antenna
extension cable inside the product, as close as possible to the module. When the PCB is routed, pay attention to The
SIM_CLK signal is protected, and the SIM_DATA, SIM_RST, and SIM_VDD signals of the SIM card are away from the
power source and away from the high-speed signal line. If the processing is not easy, it may cause problems such as
not knowing the card or dropping the card. Therefore, please follow the following principles when designing:
Keep the SIM card holder away from the antenna during the PCB layout phase;
Keep the SIM card away from the RF line, VBAT, and high-speed signal lines, and do not leave the SIM card too
long.
The GND of the SIM card holder should be in good communication with the GND of the module to make the
GND equipotential between the two.
To prevent SIM_CLK from interfering with other signals, it is recommended to protect SIM_CLK.
It is recommended to place a 100nF capacitor on the SIM_VDD signal line near the SIM card holder.
Place TVS near the SIM card holder. The parasitic capacitance of the TVS should not exceed 50pF. The 51Ω
resistor in series with the module can enhance ESD protection.
The SIM card signal line increases the capacitance of 22pf to ground to prevent radio frequency interference.
The VBAT's return path has a large current, so the SIM card trace should avoid the VBAT return path.
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MIPI is a high-speed signal line. Users must pay attention to protection during the layout phase, so that they are
away from the signal lines that are easily interfered. The GND processing must be performed on the upper and lower
sides, and the traces are differential pairs. 100 ohm differential impedance matching is performed. Ensure
impedance consistency and do not bridge different GND planes as much as possible.
The MIPI interface selects a small-capacity TVS when selecting an ESD device. It is recommended that the parasitic
capacitance be less than 1pF.
The MIPI routing requirements are as follows:
The total length of the cable does not exceed 305mm
It is required to control 100 ohm differential impedance with an error of ±10%.
The error of the differential line length within the group is controlled within 0.7mm.
The length error between groups is controlled within 1.4mm.
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The module supports high-speed USB interface at a rate of 480Mbps. The user recommends adding a common-
mode inductor during the schematic design phase to effectively suppress EMI interference. If you need to increase
the static protection, please select a TVS tube with a parasitic capacitance of less than 1pF. Please refer to the
following notes when planning:
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