3. TECHNICAL BRIEF
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O nly for training and service purposes
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3. TECHNICAL BRIEF
3.11.3 Microphone Supply
See Figure 3.11.3 for the differential connection of microphone. This is the application circuits compatible with
previous products. C1 and Rin form an AC coupling and high-pass network. C1*Rin is selected so that the in-band
signal will not be attenuated too much. For differential minimum 13k resistance, the minimum value of C1 is 170uF
for less than 1dB attenuation at 300hz. R2 is determined by the sensitivity of microphone . C2 and R2 form another
low –pass filter filtering noise coming from the microphone bias pins.
Pole frequency that is less than 50 Hz is recommended.
Figure 3.11.3 Typical Microphone Supply Generation (alternative)
3.11.3 Microphone Supply
AU_MICBIAS_P
AU_VIN0_P
AU_VIN0_N
Rin> 13KΩ
R
R1
R1
R
C1
C1
C