AK4558EN Datasheet, PDF (64/94 Pages) Asahi Kasei Microsystems – 108dB 216kHz 32Bit CODEC with PLL

[AK4558]
■ Out of Band Noise Reduction Filter
The AK4558 has an out of band noise reduction filter that can change frequency response. This FIR
filter attenuates out of band noise and prevents a degradation of the analog characteristics caused
by a switching regulator, etc. FIRDA2-0 bits set the frequency for noise attenuation. (Table 32)
FIRDA2-0 bits
000
001
010
011
100
101
110
111
FIR filter
FIR filter
Mode
0
1/4*[1 1 1 1 0 0 0 0 0 0 0 0 0 0 0 0]
1
1/4*[1 1 0 0 0 0 0 0 0 0 0 0 0 0 1 1]
2
1/4*[1 0 1 0 0 0 0 0 0 0 0 0 0 1 0 1]
3
1/4*[1 0 0 1 0 0 0 0 0 0 0 0 1 0 0 1]
4
1/4*[1 0 0 0 1 0 0 0 0 0 0 1 0 0 0 1]
5
1/4*[1 0 0 0 0 1 0 0 0 0 1 0 0 0 0 1]
6
1/4*[1 0 0 0 0 0 1 0 0 1 0 0 0 0 0 1]
7
1/4*[1 0 0 0 0 0 0 1 1 0 0 0 0 0 0 1]
Table 32. FIR Filter Setting
(default)
Figure 41. Mode0 FIR Filter
015004500-E-02
Figure 42. Mode1 FIR Filter
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2015/09