Reference Design For Microphone Interfaces - Quectel SC200K Series Instruction Manual

HPH_L 138
HS_DET 139
MIC_BIAS 147
MIC3_P 148
MIC3_M 149
⚫
The module offers three input channels, including two differential channels and one single-ended
channel.
⚫
The output voltage range of MIC_BIAS is programmable between 2.2 V and 3.0 V. The maximum
output current is 2 mA.
⚫
The earpiece interface uses differential output.
⚫
The loudspeaker interface uses differential output as well. The output channel is available with a
Class-D amplifier whose output power is up to 0.8 W when load is 8 Ω.
⚫
The headphone interface features stereo left and right channel output, and supports headphone
insertion detection.
⚫
The 3 microphone inputs of the module are all integrated with a bias voltage inside the module and
support ECM microphone only. External bias voltage is not needed.

4.12.1. Reference Design for Microphone Interfaces

Module
SC200K_Series_Hardware_Design
AO Headphone left channel output
AI Headset hot-plug detect
Bias voltage output for
PO
microphone
AI Auxiliary microphone input (+)
AI Auxiliary microphone input (-)
MIC1_P
MIC1_M
GND
Figure 26: Reference Circuit Design for Main Microphone
C1
NM
C3
C2
NM NM
Smart Module Series
High level by default.
F1
1
MIC_P
2
MIC_N
F2
ECM MIC
D2
D1
R5
NM
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