AK4490EN Datasheet, PDF (41/68 Pages) Asahi Kasei Microsystems – Premium 32-Bit 2ch DAC

[AK4490EN]
■ 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.
Table 24. De-emphasis Control
DEM1 DEM0 Mode
0
0
44.1kHz
0
1
OFF (default)
1
0
48kHz
1
1
32kHz
■ Output Volume (PCM, DSD)
The AK4490EN 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 7395/fs from FFH (0dB) to 00H (MUTE). The attenuation level is
initialized to FFH by setting to PDN pin = “L”. Register setting values will be kept even switching the PCM
and DSD modes.
Table 25. ATT Transition Time
Sampling Speed
Transition Time
0dB to MUTE
fs=44.1kHz
168.3ms
fs=96kHz
77.3ms
fs=192kHz
38.6ms
015013666-E-01
- 41 -
2015/12