Smart Machine Smart Decision
5. PCB Layout
Usually, most electronic products with good performance are based on good PCB layout. A bad PCB layout will
lead to lots of issues, like TDD noise,
SIM card not be detected, etc. the final solution for these problems is to
redo PCB layout. Making good PCB layout at beginning will save develop schedule and cost as well.
This section will give some guidelines on PCB layout, in order to eliminate interfere
or noise by greatest degree,
and save product development period.
5.1 Pin Assignment
Before PCB layout, we should learn well about pin assignment in order to get reasonable layout with so many
external components. Following figure is the overview of pin assignment of the module.
Figure 54: Pin assignment
SIM800H&SIM800L_Hardware Design_V2.02 55
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Smart Machine Smart Decision
SIM800H&SIM800L_Hardware Design_V2.02 56
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5.2 Principle of PCB Layout
During layout, attention should be paid to
the following interfaces, like Antenna, power supply, SIM card
interface, audio interface, and so on.
5.2.1 Antenna Interface
z The length of trace between pin output and connector
should be as short as possible;
z Do not trace RF signal over across the board;
z The RF signal should be far away from SIM card, power ICs.
