Quectel EG915U-EU - Microphone Interface Design

LTE Standard Module Series
EG915U-EU_Hardware_Design 39 / 81
should be far away from the audio traces.
The differential audio traces must be routed according to the differential signal layout rule.
4.1.2. Microphone Interface Design
The microphone channel reference circuit is shown in the following figure.
MIC_P
Differential
layout
Module
10 pF
33 pF
33 pF
33 pF
Electret
Microphone
10 pF
10 pF
TVS
TVS
Close to Module
MIC_N
MIC_BIAS
Close to
Microphone
2.2uF
100nF
1K
0R
0R
100nF
1K
510R
510R
1.5K
1.5K
Figure 16: Reference Design for Microphone Interface
MIC channel is sensitive to ESD, so it is not recommended to remove the ESD components used for
protecting the MIC.
NOTE