GSM/GPRS Module
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from audio interface and audio alignment. Power alignment and audio alignment should not be parallel,
and power alignment should be far away from audio alignment.
The differential audio traces have to be placed according to the differential signal layout rule.
3.8.2. Microphone Interfaces Design
AIN1 and AIN2 channels come with internal bias supply for external electret microphone. A reference
circuit is shown in the following figure.
Close to Microphone
MICxP
MICxN
Differential layout
Module
Electret
Microphone
GND
33pF
0603
33pF
0603
GND
10pF
0603
10pF
0603
ESD
ESD
10pF
0603
33pF
0603
Figure 27: Reference Design for AIN1&AIN2
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