
ASAHI KASEI 
[AK4346] 
MS0531-E-00 
2006/07 
- 16 - 
 De-emphasis Filter 
A digital de-emphasis filter is available for 32, 44.1 or 48kHz sampling rates (tc = 50/15
μ
s). The digital de-emphasis 
filter is always off when the AK4346 is operated in double or quad speed modes. In serial control mode, the DEM0-1 bits 
are valid for the DAC enabled by the DEMA-C bits. In parallel control mode, the DEM0-1 pins are valid. 
DEM1
DEM0
0 
0 
0 
1 
1 
0 
1 
1 
Mode 
44.1kHz
OFF 
48kHz 
32kHz 
Table 9. De-emphasis Filter Control (Normal Speed Mode) 
 Output Volume 
The AK4346 includes channel independent digital volume controls (ATT) with 256 linear steps, including MUTE. The 
volume controls 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; thus no switching noise occurs during these transitions. The transition 
time of 1 level and all 256 levels is shown in Table 10. The attenuation level is calculated by ATT = 20 log
10
(ATT_DATA / 255)  [dB] and MUTE at ATT_DATA = “0”. 
Sampling Speed 
1 Level 
Normal Speed Mode 
4LRCK 
Double Speed Mode 
8LRCK 
Quad Speed Mode 
16LRCK 
Transition Time 
255 to 0 
1020LRCK 
2040LRCK 
4080LRCK 
Table 10. ATT Transition time 
Zero Detection
When the input data at all channels are continuously zeros for 8192 LRCK cycles, the AK4346 has a Zero Detect function 
detailed in Table 11. The DZF pin immediately goes to “L” if the input data for each channel is not zero after the DZF pin 
is  “H”. If the RSTN bit is “0”, the DZF pin goes to “H”. The DZF pin goes to “L” after 4 to 5LRCK cycles if the input data 
of each channel is not zero after the RSTN bit returns to “1”. The Zero Detect function can be disabled by the DZFE bit. 
In this case, both DZF pins are always “L”. When one of the PW1-3 bits is set to “0”, the input data of the DAC for which 
the PW bit is set to “0” should be zero in order to enable zero detection of the other channels. When all PW1-3 bits are set 
to “0”, both DZF pins are fixed to “L”. The DZFB bit can invert the polarity of the DZF pin. In parallel control mode, the 
zero detect function is disabled and the DZF1 pin is fixed to “L”. 
DZF Pin 
DZF1 
AND’ed output of zero detection flag of each channel set to “1” in 0CH register 
DZF2 
AND’ed output of zero detection flag of each channel set to “1” in 0DH register 
Operations 
Table 11. DZF pins Operation