Quectel M20 Hardware Design page 53

M20 Hardware Design
SPK2P
Module
AGND
Figure 29: Speaker interface configuration of AOUT2
SPK2P
Module
AGND
Figure 30: Speaker interface with amplifier in AOUT2
Note: The value of C1 and C2 depends on the input impedance of audio amplifier .
M20_HD_V1.01
Differential layout
Differential layout
C1
C2
Close to speaker
10pF
Close to speaker
Amplifier
10pF
circuit
10pF
GND
ESD
33pF
ANTI
GND
ESD
33pF
ANTI
ESD
33pF
ANTI
GND
- 52 -