AK4620A Datasheet, PDF (40/42 Pages) Asahi Kasei Microsystems – 24 BIT 192KHZ AUDIO CODEC WITH IPGA

ASAHI KASEI
[AK4620A]
It is recommended by SACD format book (Scarlet Book) that the filter response at SACD playback is an analog low pass
filter with a cut-off frequency of maximum 50kHz and a slope of minimum 30dB/Oct. The AK4620A can achieve this
filter response by combination of the internal filter (Table 20) and an external filter (Figure 20).
Frequency
Gain
20kHz
−0.4dB
50kHz
−2.8dB
100kHz
−15.5dB
Table 20. Internal Filter Response at DSD mode
AOUT-
2.0k
2.8Vpp
2200p
2.0k
AOUT+
2.8Vpp
1.8k
3300p
1.8k
4.3k
4.3k
1.0k
1.0k
270p
270p
+Vop
-
+
-Vop
Analog
Out
6.34Vpp
Figure 20. External 3rd order LPF Circuit Example for DSD
Frequency
Gain
20kHz
−0.05dB
50kHz
−0.51dB
100kHz
−16.8dB
DC gain = 1.07dB
Table 21. 3rd order LPF (Figure 20) Response
MS0368-E-00
- 40 -
2004/12