AK4490 Datasheet, PDF (63/68 Pages) Asahi Kasei Microsystems – Premium 32-Bit 2ch DAC

[AK4490]
It is recommended for 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 AK4490
can achieve this filter response by combination of the internal filter (Table 32) and an external filter (Figure 42).
Frequency
Gain
20kHz
0.4dB
50kHz
2.8dB
100kHz
15.5dB
Table 32. Internal Filter Response at DSD Mode
AOUT-
2.0k
2.8Vpp
2200p
AOUT+
+
2.0k
2.8Vpp
1.8k
3300p
1.8k
4.3k
4.3k
1.0k
1.0k
270p
270p
+Vop
-
+
-Vop
Analog
Out
6.34Vpp
Figure 42. External 3rd Order LPF Circuit Example for DSD
Frequency
Gain
20kHz
0.05dB
50kHz
0.51dB
100kHz
16.8dB
DC gain = 1.07dB
Table 33. 3rd Order LPF (Figure 42) Response
MS1648-E-03
- 63 -
2014/11