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HUAWEI MU509-65 HSDPA LGA Module
Hardware Guide
3.8 Audio Interface
3.8.1 Analogue Audio
The MU509-65 provides two audio I/O channels. The two audio I/O channels are
completely different and thus have good performance of resisting RF interferences.
The routes on the printed circuit board (PCB) should be placed in parallel with each
other and should be short. The filter circuit on the two sides should be symmetric. The
differential signals should be close to each other. The audio output signals in
differential pairs and the audio input signals in differential pairs should be separated
effectively through ground. In addition, the audio signals should be located away from
the circuits of the power supply, RF, and antenna.
The first audio channel can be used for the handset without requiring any audio
amplifier. The output power for the differential ear is typically 50 mW.
The second audio channel can be used for the hands-free without requiring any audio
amplifier. The output pins are configured differently, with a rated output of 500 mW.
Considerable current flows between the audio output pins and the speaker, and thus
wide PCB traces are recommended (20 mils).
Figure 3-21 Circuit diagram of the interface of the first audio channel
Issue 01 (2016-04-08)
MIC1_P
MIC1_N
33 pF
Module
(DCE)
EAR_OUT_P
EAR_OUT_N
33 pF
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Description of the Application Interfaces
100 pF
33 pF
100 pF
33 pF
ESD protection
Network
Connector
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