GSM/GPRS Module
M85 Hardware Design
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Module
SPK2P
AGND
Differential layout
Amplifier
circuit
10pF
0603
10pF
0603
33pF
0603
33pF
0603
Close to Speaker
GND
GND
ESD
ESD
C2
C1
Figure 30: Speaker Interface Design with an Amplifier for AOUT2
Texas Instrument’s TPA6205A1is recommended for a suitable differential audio amplifier. There are
plenty of excellent audio amplifiers in the market.
3.
The value of C1 and C2 here depends on the input impedance of audio amplifier.
3.8.4. Earphone Interface Design
Amphenol
9001-8905-
050
1
2
4
3
SPK2P
MIC2N
MIC2P
22uF
68R
GND
GND
AGND
Close to Socket
Differential layout
AGND
GND GND
GND
GND
AGND
Module
4.7uF
33pF
0603
10pF
0603
33pF
0603
10p
F
0603
ESD
ESD
Figure 31: Earphone Interface Design
NOTE
Quectel
Confidential