CS5509(1995) View Datasheet(PDF) - Cirrus Logic
Part Name
Description
Manufacturer
CS5509 Datasheet PDF : 30 Pages
| |||
0
-20
X1 = 32.768kHz
X2 = 330.00kHz
-40
-60
-80
-100
-120
-140
-160
X1 0
X2 0
XIN = 32.768 kHz
40 80 120 160 200 240
402.83 805.66 1208.5 1611.3 2014.2 2416.9
Frequency (Hz)
Figure 6. Filter Magnitude Plot to 260 Hz
0
-20
-40
-60
-80
-100
-120
Flatness
Frequency dB
1
-0.010
2
-0.041
3
-0.093
4
-0.166
5
-0.259
6
-0.374
7
-0.510
8
-0.667
9
-0.846
10 -1.047
17 -3.093
XIN = 32.768 kHz
-140
0
5 10 15 20 25 30 35 40 45 50
Frequency (Hz)
Figure 7. Filter Magnitude Plot to 50 Hz
CS5509
Frequency
(Hz)
50
60
100
120
150
180
200
240
Notch
Depth
(dB)
125.6
126.7
145.7
136.0
118.4
132.9
102.5
108.4
Frequency
(Hz)
50±1%
60±1%
100±1%
120±1%
150±1%
180±1%
200±1%
240±1%
Minimum
Attenuation
(dB)
55.5
58.4
62.2
68.4
74.9
87.9
94.0
104.4
Table 2. Filter Notch Attenuation (XIN = 32.768 kHz)
180
135
90
45
0
-45
-90
-135
XIN = 32.768 kHz
-180
0
5 10 15 20 25 30 35 40 45 50
Frequency (Hz)
Figure 8. Filter Phase Plot to 50 Hz
Digital Filter Characteristics
The digital filter in the CS5509 is the combina-
tion of a comb filter and a low pass filter. The
comb filter has zeros in its transfer function
which are optimally placed to reject line interfer-
ence frequencies (50 and 60 Hz and their
multiples) when the CS5509 is clocked at
32.768 kHz. Figures 6, 7 and 8 illustrate the
magnitude and phase characteristics of the filter.
14
Figure 6 illustrates the filter attenuation from dc
to 260 Hz. At exactly 50, 60, 100, and 120 Hz
the filter provides over 120 dB of rejection. Ta-
ble 2 indicates the filter attenuation for each of
the potential line interference frequencies when
the converter is operating with a 32.768 kHz
clock. The converter yields excellent attenuation
of these interference frequencies even if the fun-
damental line frequency should vary ± 1% from
DS125F1
Share Link: 