GSM/GPRS Module Series
M66 Hardware Design
M66_Hardware_Design Confidential / Released 44 / 80
3.8.4. Earphone Interface Design
1
2
4
3
MICP
22uF
33pF
GND
AGND
Close to Socket
AGND
33pF
10pF
GND
AGND
Module
4.7uF
SPK2P
Close to Module
GND
33pF
33pF
Differential
layout
33pF
MICN
0603
0603
0603
0603
0603
0603
0603
10pF
GND
10pF
0603
0603
0603
10pF
10pF
Figure 27: Earphone Interface Design
3.8.5. Audio Characteristics
Table 10: Typical Electret Microphone Characteristics
Table 11: Typical Speaker Characteristics
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
Parameter
Min.
Typ.
Max.
Unit
AOUT1
Output
Single-ended
Load resistance
32
Ohm
Ref level
0
2.4
Vpp
Differential
Load resistance
32
Ohm
Ref level
0
4.8
Vpp
Quectel
Confidential