AK4495EQ Datasheet, PDF (36/63 Pages) Asahi Kasei Microsystems – Quality-oriented Premium 32-Bit 2ch DAC

[AK4495S/95]
■ D/A Conversion Mode Switching Timing
RSTN bit
D/A Mode
D/A Data
4/fs
PCM Mode
DSD Mode
0
PCM Data
DSD Data
Figure 18. D/A Mode Switching Timing (PCM to DSD)
RSTN bit
D/A Mode
D/A Data
DSD Mode
PCM Mode
4/fs
DSD Data
PCM Data
Figure 19. D/A Mode Switching Timing (DSD to PCM)
Note. The signal range is identified as 25% ~ 75% duty ratios in DSD mode. DSD signal must not go beyond
this duty range at the SACD format book (Scarlet Book).
■ 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 21. De-emphasis Control
■ Output Volume (PCM, DSD)
The AK4495S/95 includes channel independent digital output volumes (ATT) with 255 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, transitions are executed in soft change; thus no switching noise
occurs during these transitions. It takes 7424/fs to attenuate from FFH (dB) to 00H (MUTE). When initial
timing reset is executed, the attenuation level is reset to FFH. Setting RSTN bit to “0” initializes the attenuation
level to FFH and setting RSTN bit to “1” release the attenuation level to the setting value. Register values will
not be changed by switching PCM mode and DSD mode.
Sampling Speed
Transition Time
0dB to MUTE
fs = 44.1kHz
168.3ms
fs = 96kHz
77.3ms
fs = 192kHz
38.6ms
Table 22. ATT Transition Time
MS1560-E-02
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2014/04