Earphone Interface Configuration; Audio Electronic Characteristics - SimCom SIM900D Hardware Design

4.7.3

Earphone Interface Configuration

4.7.4

Audio Electronic Characteristics

Table 9: Microphone Input Characteristics
Parameter
Working Voltage
Working Current
External Microphone Load Resistance
Internal biasing DC Characteristics
Differential input THD
voltage F=1KHz; pre-amp
gain = 20 dB;
PGA gain = 14 dB
THD
F=1KHz;pre-amp
gain = 0 dB; PGA
gain = 0 dB
SIM900D_Hardware Design_V2.02
Figure 27: Earphone reference circuit
Min
1.2
200
1.2
<1% at
<5% at
Typ Max
1.5 2.0
500
2.2
2.5
15.9
740
33
Smart Machine Smart Decision
Unit
V
uA
kΩ
V
mVrms
mVrms
2012-05-07