CS42438_07 Datasheet, PDF (51/61 Pages) Cirrus Logic – 108 dB, 192 kHz 6-In, 8-Out TDM CODEC

8.1.1
CS42438
Passive Input Filter
The passive filter implementation shown in Figure 22 will attenuate any noise energy at 6.144 MHz but
will not provide optimum source impedance for the ADC modulators. Full analog performance will there-
fore not be realized using a passive filter. Figure 22 illustrates the unity gain, passive input filter solution.
In this topology the distortion performance is affected, but the dynamic range performance is not limited.
100 kΩ
150 Ω
10 μF
2700 pF
C0G
ADC1-2
AIN1+,2+,3+,4+
4.7 μF
AIN1-,2-,3-,4-
100 kΩ
150 Ω
10 μF
2700 pF
C0G
ADC3
AIN5A,6A
100 kΩ
150 Ω
10 μF
2700 pF
C0G
AIN5B,6B
Figure 22. Passive Input Filter
DS646F2
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