AK4355 Datasheet, PDF (13/24 Pages) Asahi Kasei Microsystems – 192kHz 24-Bit 6ch DAC for DVD-Audio

ASAHI KASEI
[AK4355]
n De -emphasis Filter
A digital de-emphasis filter is available for 32, 44.1 or 48kHz sampling rates (tc = 50/15µs) and is enabled or disabled with
DEM0 and DEM1. In case of double speed and quad speed mode, the digital de-emphasis filter is always off.
DEM1
0
0
1
1
DEM0
0
1
0
1
Mode
44.1kHz
OFF
48kHz
32kHz
Default
Table 8. De-emphasis Filter Control (Normal Speed Mode)
n Output Volume
The AK4355 includes channel independent digital output volumes (ATT) with 256 levels including MUTEand 0.5dB step .
These volumes are in front of the DAC and can attenuate the input data from 0dB to –127dB and mute. Transition time is set
by AST1-0 bits(Table10).In Mode0 and Mode1, when changing levels, transitions are exe cuted via soft changes; thus no
switching noise occurs during these transitions.
ATT7-0
FFH
FEH
FDH
:
02H
01H
00H
Attenuation Level
0dB
-0.5dB
-1.0dB
:
-126.5dB
-127.0dB
MUTE (-∞)
Default
Table 9. Attenuation Level of Output Volume
Mode
0
1
2
3
ATS1
0
0
1
1
ATS0
0
1
0
1
ATT speed
7424/fs
1061/fs
256/fs
Reserved
Default
Table 10. Transition time of output volume
In case of Mode0, it takes 7424/fs(168ms@fs=44.1k) to transit from FFH(0dB) to 00H( MUTE). In case of Mode1, it takes
1061/fs(24ms@fs=44.1k) to transit from FFH(0dB) to 00H(MUTE). In case Mode2 and 3,it takes 256/ fs(6ms@fs=44.1k) to
transit from FFH(0dB) to 00H(MUTE). If PDN pin goes to “L”, ATT7-0 registers are initialized to FFH.ATTN7-0 registers go
to FFH when RSTN bit is set to“0”. When RSTN bit returns to “1”, ATT7-0 registers go to the set value. Digital output
volume function is independent of soft mute function.
MS0063-E-01
- 13 -
2002/07