GSM/GPRS Module Series
M85 Hardware Design
M85_Hardware_Design Confidential / Released 49 / 88
3.8.5. Loud Speaker Interface Design
LOUDSPKP
LOUDSPKN
Differential layout
10pF
10pF
33pF
33pF
Close to Speaker
GND
GND
100pF
ESD
ESD
Module
0R
0R
0603
0603
0603
0603
Figure 31: Loud Speaker Interface Design
3.8.6. 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
Ω
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