Cirrus Logic CS42L51 - Manual (Page 78)

78 DS679F1
CS42L51
7.3 ADC_FILT+ Capacitor Effects on THD+N
The value of the capacitor on the ADC_FILT+ pin, 16, affects the low frequency total harmonic distortion +
noise (THD+N) performance of the ADC. Larger capacitor values yield significant improvement in THD+N
at low frequencies.
Figure 33 shows the THD+N versus frequency for the ADC analog input. Plots were tak-
en from the CDB42L51 using an Audio Precision analyzer.
-100
-60
-96
-92
-88
-84
-80
-76
-72
-68
-64
d
B
F
S
20 20k 50 100 200 500 1k 2k 5k 10k
Hz
Figure 33. ADC THD+N vs. Frequency w/Capacitor Effects
1 µF
Legend –
Capacitor Value on ADC_FILT+
10 µF
22 µF