AK4490EQ Datasheet, PDF (40/68 Pages) Asahi Kasei Microsystems – Premium 32-Bit 2ch DAC

[AK4490]
■ De-emphasis Filter
A digital de-emphasis filter is available for 32kHz, 44.1kHz or 48kHz sampling rates (tc = 50/15µs) and is
enabled or disabled with DEM1-0 pins or DEM1-0 bits. In case of 256fs/384fs and 128fs/192fs, the digital
de-emphasis filter is always off. When DSD mode, DEM1-0 bits are ignored. The setting value is held even if
PCM mode and DSD mode are switched.
DEM1 DEM0 Mode
0
0
44.1kHz
0
1
OFF (default)
1
0
48kHz
1
1
32kHz
Table 23. De-emphasis Control
■ Output Volume (PCM, DSD)
The AK4490 includes channel independent digital output volumes (ATT) with 256 levels at 0.5dB step
including MUTE. This volume control is in front of the DAC and it can attenuate the input data from 0dB to
–127dB or mute. When changing output levels, it is executed in soft transition thus no switching noise occurs
during these transitions. It takes 7424/fs from FFH (0dB) to 00H (MUTE). The attenuation level is initialized
to FFH by initial reset. Register setting values will be kept even switching the PCM and DSD modes.
Sampling Speed
Transition Time
0dB to MUTE
fs=44.1kHz
168.3ms
fs=96kHz
77.3ms
fs=192kHz
38.6ms
Table 24. ATT Transition Time
MS1648-E-03
- 40 -
2014/11