Data Sheet

Smart Machine Smart Decision
SIM800F_Hardware Design_V1.00 50 2015-07-31
5.2 Principle of PCB Layout
During layout, we should pay attention to the following interfaces, such as Antenna, power supply, SIM card
interface, audio interface and so on.
5.2.1 Antenna
 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.