Quectel M12

M12 Hardware Design
M12_Hardware_Design_V3.3 - 49 -
Module
SPK2P
AGND
Differential layout
Amplifier
circuit
10pF
0603
Close to speaker
GND
ESD
C2
C1
33pF
0603
33pF
0603
GND
10pF
0603
ESD
Figure 31: Reference design with an amplifier for AOUT2
Note: The value of C1 and C2 depends on the input impedance of audio amplifier.
3.9.4. Earphone interface configuration
Amphenol
9001-8905-050
1
2
4
3
SPK2P
MIC2N
MIC2P
22uF
68R
AGND
Close to Socket
Differential
layout
AGND
AGND
Module
4.7uF
ESD
GND
33pF
0603
10pF
0603
33pF
0603
GND
10pF
0603
ESD
Figure 32: Reference design for an earphone
Table 11: Typical electret microphone characteristic
Parameter
Min
Typ
Max
Unit
Working Voltage
1.2
1.5
2.0
V
Working Current
200
500
uA
External Microphone Load Resistance
2.2
k Ohm
Quectel
Confidential