User's Manual

SIM900B Hardware Design
3.9.4 Referenced Electronic Characteristic
Table 10: MIC Input Characteristics
Parameter Min Typ Max Unit
Working Voltage 1.2 1.5 2.0 V
Working Current 200 500 uA
External Microphone Load Resistance 1.2 2.2 k Ohms
Internal biasing DC Characteristics 2.5 V
THD <1% at
F=1KHz; pre-amp
gain = 20 dB;
PGA gain = 14 dB
15.9 mVrms Differential input
voltage
THD <5% at
F=1KHz;pre-amp
gain = 0 dB; PGA
gain = 0 dB
740 mVrms
Table 11: Audio Output Characteristics
Parameter Conditions Min Typ Max Unit
load Resistance 27 32 - Ohm
Biasing voltage 1.4 V
Output swing
Voltage(single)
1.1V Vpp
Output swing
Voltage(differentia
l)
2.2 Vpp
RL=32 Ohm
THD=0.1%
- 91 - mW
Normal
Output(SPK1P/1N
)
RL=32 Ohm
THD=1%
- 96 - mW
load Resistance 27 32 - Ohm
Biasing voltage 1.4 V
Normal
Output(SPK2P/2N
)
Output swing
Voltage(single)
1.1V V
SIM900B_HD_V1.03 24.06.2010
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