AK4683_07 Datasheet, PDF (45/84 Pages) Asahi Kasei Microsystems – Asynchronous Multi-Channel Audio CODEC with DIR/T

[AK4683]
■ Output Analog Volume (OPGA)
Volume range of the output analog volume is 0dB to -50dB and MUTE with by zero crossing detection. The OPGA is
operated by the clock for DAC. The zero crossing detection of Lch and Rch is worked independently. If there are no
zero-crossings, the level will then change after a timeout period; the timeout period scales with fs. When ZCE is “0”, it
is changed immediately without zero crossing detection.
When writing to OPGA4-0 bits continually, it should take an interval of zero crossing timeout period or more. If the
OPGA4-0 bits are changed before zero crossing, the volume of Lch and Rch may differ. When the volume that is same
as the present is set, the zero crossing counter isn’t reset and timeout according to the previous writing timing.
OPGA4-0
1FH
1EH
1DH
:
10H
0FH
0EH
0DH
:
05H
04H
03H
02H
01H
00H
GAIN(dB)
+0
-1
-2
:
-15
-16
-18
-20
:
-36
-38
-42
-46
-50
MUTE
STEP
1dB
2dB
4dB
LEVEL
17
11
3
1
(default)
Table 42. Output Analog Volume Setting
When ZCE bit is “1”, the Lch/Rch volume level are changed independently by zero crossing detection or zero crossing
timeout operation. The count of timer is doubled when DAC double speed mode, four times when DAC quad speed
mode.
DAC2 Sampling Speed
Normal Speed Mode
Double Speed Mode
Quad Speed Mode
Zero crossing timeout
768/fs (16ms @fs=48kHz)
1536/fs (16ms @fs=96kHz)
3072/fs (16ms @fs=192kHz)
Table 43. Zero crossing timeout
The OPGA is enable at PWDA bit = PWDA2 bit = “1”. The initializing of OPGA starts when DAC is powered up. This
initializing cycle is 96ms(@fs=48kHz). Writing to the OPGA4-0 during the initialization is ignored. The default volume
value is mute after power up. Initialization time is 512/fs+96ms(@fs=48kHz) after PDN pin = “H”.
DAC2 Sampling Speed
Normal Speed Mode
Double Speed Mode
Quad Speed Mode
OPGA Initialization Time
4608/fs (96ms @fs=48kHz)
9216/fs (96ms @fs=96kHz)
18432/fs (96ms @fs=192kHz)
Table 44. OPGA Initialization Time
MS0427-E-02
- 45 -
2007/04