AK4620BVFP-E2 Datasheet, PDF (23/42 Pages) List of Unclassifed Manufacturers – 24-Bit 192kHz Audio CODEC with IPGA

ASAHI KASEI
[AK4620B]
„ Input Volume
The AK4620B includes two channel-independent analog volumes (IPGA), each with 32 levels in 0.5dB increments.
These are located in front of the ADC while digital volume controls (IATT) with 128 levels (including MUTE) are
located after the ADC. Control of both of these volume settings is handled by the same register address. When the MSB of
the register is “1”, the IPGA changes and when the MSB = “0” the IATT changes.
The IPGA is an analog volume control that improves the S/N ratio compared with digital volume controls (Table 11).
Level changes only occur during zero-crossings to minimize switching noise. Channel independent zero-crossing
detection is used. If there are no zero-crossings, then the level will change after a time-out. The time-out period scales
with fs. The periods of 256/fs, 512/fs, 1024/fs and 2048/fs are selected by ZTM1-0 bits in normal speed mode. If a new
value is written to the IPGA register before the IPGA changes at the zero crossing or time-out, the previous value
becomes invalid. The timer (channel independent) for time-out is reset and the timer restarts for the new IPGA value.
ZCEI bits in the control register enable zero-crossing detection.
The IATT is a log volume that is linear-interpolated internally. When changing the level, the transition between ATT
values has 29 levels and is done by soft changes, eliminating any switching noise.
Input Gain Setting
0dB
+6dB
fs=44.1kHz, A-weight
110dB
108dB
Table 11. IPGA+ADC S/N (typ.)
+18dB
101dB
ZTM1
0
0
1
1
ZTM0
Normal speed Double speed
0
256/fs
512/fs
1
512/fs
1024/fs
0
1024/fs
2048/fs
1
2048/fs
4096/fs
Table 12. LRCK cycles for timeout period
Quad speed
1024/fs
2048/fs
4096/fs
8192/fs
Default
„ Output Volume
The AK4620B includes channel independent digital output volumes (ATT) with 256 levels at linear steps including
MUTE. These volumes are in front of the DAC and can attenuate the input data from 0dB to −48dB and mute. When
changing levels, transitions are executed via soft changes, eliminating any switching noise. The transition time of 1 level
and all 256 levels is shown in Table 13.
Sampling Speed
Transition Time
1 Level
255 to 0
Normal Speed Mode
4LRCK
1020LRCK
Double Speed Mode
8LRCK
2040LRCK
Quad Speed Mode
16LRCK
4080LRCK
Table 13. ATT Transition Time
MS0401-E-00
- 23 -
2005/07