SimCom SIM900 Reference Design Guide

SIM900 Reference Design Guide Notes
2.4.1 Referenced circuit of headset design
Figure 9: Referenced circuit of headset
2.4.2 Referenced circuit of hand free design
Figure 10: Referenced circuit of audio PA
2.5 Antenna matching circuit design
Because the module is working under 50ohm system in RF part, so, to get the best RF
performance, the SMT module’s load impedance should be tuned to 50ohm. But in fact, the most
antenna’s port impedance is not a purely 50ohm, so, to meet the 50ohm requirement, an additional
SIM900_AN_Reference Design Guide_V1.01 01.27.2010
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SimCom SIM900 Specifications

General

Brand	SimCom
Model	SIM900
Category	Modem
Language	English