Speaker Interface; Microphone Bias - Sunsea AIoT SIMCom SIM5800 Hardware Design

4.12.4 Speaker Interface

The module is integrated with a Class-D audio amplifier. Parameters are shown in the following table:
Table 15: Performance parameters of the speaker
Parameters
Power
THD+N
(1 kHz)
Efficiency
Static current
Reference circuit is follow:
Module
SPK_P
SPK_N

4.12.5 Microphone Bias

The module provides two-channel microphone bias voltage output: MIC_BIAS0 and MIC_BIAS1. Users can
supply power to external silicon microphones. The output voltage can be set to 1.9v, 2.0v, 2.1v and 2.2v through
the software. The default voltage is 1.9v.
The internal block diagram is following:
SIM5800_Hardware Design_V1.01
Smart Machine Smart Decision
Test Condition
8 Ω load, VBAT= 4.2 V THD+N=1%
8 Ω load, VBAT= 3.8 V THD+N=1%
8 Ω load, VBAT= 3.4 V THD+N=1%
8 Ω load, VBAT= 4.2 V THD+N=10%
8 Ω load, VBAT= 3.8 V THD+N=10%
8 Ω load, VBAT= 3.4 V THD+N=10%
Pout=0.5Wrms VBAT=4.2V
Pout=0.4Wrms VBAT=3.8V
Pout=0.3Wrms VBAT=3.4V
VBAT=4.2V 0.5W 8Ω 68uH 1kHz
VBAT=3.8V 0.5W 8Ω 68uH 1kHz
& shielded by GND
33pF
10pF
33pF
10pF
33pF
10pF
Figure 29: Reference circuit of the speaker
Min
-
-
-
differential signal
10pF
10pF
10pF
38
Typ Max Unit
900 - mW
700 - mW
500 - mW
1100 mW
850 mW
600 - mW
0.1 0.2
0.1 0.2
0.1 0.2
85
85
5 -
Close to speaker
TVS
33pF
33pF
TVS
33pF
2018-10-08
%
%
%
%
%
mA