CS42526 Datasheet, PDF (75/90 Pages) Cirrus Logic – 114 dB, 192 kHz 6-Ch Codec with S/PDIF Receiver

CS42526
10. APPENDIX A: EXTERNAL FILTERS
10.1 ADC Input Filter
The analog modulator samples the input at 6.144 MHz (internal MCLK=12.288 MHz). The digital filter will
reject signals within the stopband of the filter. However, there is no rejection for input signals which are
(n × 6.144 MHz) the digital passband frequency, where n=0,1,2,... Refer to Figure 24 for a recommended
analog input buffer that will attenuate any noise energy at 6.144 MHz, in addition to providing the optimum
source impedance for the modulators. The use of capacitors which have a large voltage coefficient (such
as general purpose ceramics) must be avoided since these can degrade signal linearity.
AINL
100 kΩ
634 Ω
100 µF
470 pF
C0G
-
+
VA
2.8 kΩ
10 kΩ
91 Ω
634 Ω
3.32 kΩ
0.1 µF
100 µF ^{332 Ω}
634 Ω
470 pF
C0G
-
+
91 Ω
2700 pF
C0G
A INL1+
A INL1-
AINR
100 kΩ
634 Ω
100 µF
470 pF
C0G
-
+
VA
2.8 kΩ
10 kΩ
91 Ω
634 Ω
3.32 kΩ
0.1 µF
100 µF ^{332 Ω}
634 Ω
470 pF
C0G
-
+
91 Ω
2700 pF
C0G
A INR1+
A INR1-
Figure 24. Recommended Analog Input Buffer
10.2 DAC Output Filter
The CS42526 is a linear phase design and does not include phase or amplitude compensation for an ex-
ternal filter. Therefore, the DAC system phase and amplitude response will be dependent on the external
analog circuitry.
AOUT -
AOUT +
1800 pF
C0G
6.19 kΩ
390 pF
5.49 kΩ 2.94 kΩ
C0G
-
1.65 kΩ
5800 pF
887 Ω
C0G
1.87 kΩ
+
1200 pF
C0G
22 µF
22 µF 1 k Ω
47.5 k Ω
Analog
Out
Figure 25. Recommended Analog Output Buffer
DS585PP5
75