SimCom SIM800C, Проектирование аппаратного обеспечения

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Smart Machine Smart Decision
SIM800C_Hardware_Design_V1.02
40
2015-4-27
5.2.1 Antenna Interface
 The length of trace between pin output and connector should be as short as possible;
 Do not trace RF signal over across the board;
 The RF signal should be far away from SIM card, power ICs.
5.2.2 Power Supply
 Not only VBAT but also return GND are very important in layout;
 The positive line of VBAT should be as short and wide as possible;
 The correct flow from source to VBAT pin should go though Zener diode then huge capacitor;
 Pin 36 and Pin37 are GND signals, and shortest layout to GND of power source should be designed;
 There are 10 GND pads in the module; these pads could enhance the GND performances. On the
upper layer of these pads, do not trace any signal if possible.
5.2.3 SIM Card Interface
 SIM card holder has no anti-EMI component inside. Thus SIM card interface maybe interfered,
please pay more attention on this interface during layout;
 Ensure SIM card holder is far way from antenna or RF cable inside;
 Put SIM card holder near the module, as nearer as possible;
 Add ESD component to protect SIM_CLK, SIM_DATA, SIM_RST and SIM_VDD signals which
should be far away from power and high-speed-frequency signal.
5.2.4 Audio Interface
 The signal trace of audio should far away from antenna and power;
 The audio signal should avoid to parallel with VBAT trace.
5.2.5 Others
 It is better to trace signal lines of UART bunched, as well as signals of USB.