Referenced Circuit Of Headset Design; Referenced Circuit Of Hand Free Design; Antenna Matching Circuit Design - SimCom SIM900 Reference Design Manual

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

Antenna matching circuit design

2.5
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
8
SIM900_AN_Reference Design Guide_V1.01 01.27.2010