M80; Microphone Reference Circuit; Receiver Reference Circuit - Quectel GSM Series Audio Design Manual

2.1.4. M80

2.1.4.1. Microphone Reference Circuit

M80 provides electrets-microphone bias voltage for AIN1 and AIN2. Reference circuit for microphone is
illustrated as following figure.
Module
Figure 11：Microphone Reference Circuit for AIN1&AIN2

2.1.4.2. Receiver Reference Circuit

Module
SPK1P
SPK1N
GSM Module Audo Design Guide
Differential layout
MICxP
MICxN
Differential layout
Figure 12：Receiver Reference Circuit for AOUT1
Confidential/Release
GSM Module Audio Design Guide
Close to Microphone
GND
10pF
33pF ESD
10pF 33pF
ESD
10pF 33pF
GND
Close to speaker
GND
33pF
10pF
10pF 33pF
10pF 33pF
GND
GSM/GPRS Modules
Electret
Microphone
ESD
ESD
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