Specifications

Integra M2106+
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This document is the sole and exclusive property of Wavecom. Not to be distributed or divulged without prior written
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WA_DEV_M2106+_PTS_003-001 April, 2007
The MIC1 inputs are differential and do not include internal bias. These inputs are the standard for an
external headset or a hands-free kit.
To use these inputs with an electret microphone, bias has to be generated outside the Wireless CPU
®
according to the characteristics of this electret microphone.
These inputs are provided either for an external headset or a hands-free kit.
The input impedance is around 10kΩ +/- 30% between 400Hz and 4000Hz.
AC coupling is already embedded in the Wireless CPU
®
.
Pin description
Signal Pin # I/O Reset state I/O type Description
MIC1P 20 I High Z Analog Microphone 1 positive input
MIC1N 22 I High Z Analog Microphone 1 negative input
Differential connection
CM
MIC1P
MIC1N
Vcc
C2
R1
R2
R3
R4
Figure 13: MIC1 differential connection
Vcc = 2.8 V from the analog power supply.
R1 = R4 = from 100 to 330 Ω.
R2 = R3 =1 kΩ to 3.3 kΩ according to the microphone characteristics.
CM = 22 pF to 100 pF.
C2 = 47 µF
R1 and R4 are used as a voltage supply filter with C2.
CM must be as close to the microphone as possible. Microphone manufacturers provide this capacitor
directly soldered on the microphone.
3.9.2 Speaker Outputs