AK4456 Datasheet, PDF (46/84 Pages) Asahi Kasei Microsystems – 115dB 768kHz Advanced 32-bit DAC

[AK4456]
■ Out of Band Noise Reduction Filter (PCM mode, DSD mode)
The AK4456 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. FIR2-0 bits set the frequency for noise attenuation. The filter characteristics will differ in DSD
direct mode compared with other modes (Table 19).
FIR2-0
bits
000
001
010
011
100
101
110
111
FIR filter
Mode
0
1
2
3
4
5
6
7
FIR filter
Except DSD direct mode
DSD direct mode
1/4*[1 1 1 1 0 0 0 0 0 0 0 0 0 0 0 0] 1/2*[1 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0]
1/4*[1 1 0 0 0 0 0 0 0 0 0 0 0 0 1 1] 1/2*[0 1 0 0 0 0 0 0 0 0 0 0 0 0 1 0]
1/4*[1 0 1 0 0 0 0 0 0 0 0 0 0 1 0 1] 1/2*[0 0 1 0 0 0 0 0 0 0 0 0 0 1 0 0]
1/4*[1 0 0 1 0 0 0 0 0 0 0 0 1 0 0 1] 1/2*[0 0 0 1 0 0 0 0 0 0 0 0 1 0 0 0]
1/4*[1 0 0 0 1 0 0 0 0 0 0 1 0 0 0 1] 1/2*[0 0 0 0 1 0 0 0 0 0 0 1 0 0 0 0]
1/4*[1 0 0 0 0 1 0 0 0 0 1 0 0 0 0 1] 1/2*[0 0 0 0 0 1 0 0 0 0 1 0 0 0 0 0]
1/4*[1 0 0 0 0 0 1 0 0 1 0 0 0 0 0 1] 1/2*[0 0 0 0 0 0 1 0 0 1 0 0 0 0 0 0]
1/4*[1 0 0 0 0 0 0 1 1 0 0 0 0 0 0 1] 1/2*[0 0 0 0 0 0 0 1 1 0 0 0 0 0 0 0]
Table 19. FIR Filter Setting
(default)
Figure 39. Mode0 FIR Filter (Except DSD direct mode)
015006886-E-00
Figure 40. Mode1 FIR Filter (Except DSD direct mode)
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2015/06