AK4641 Datasheet, PDF (27/51 Pages) Asahi Kasei Microsystems – 16 BIT CODEC WITH BLUETOOTH INTERFACE

ASAHI KASEI
[AK4641]
„ DAC of Stereo CODEC
DACL bit
Stereo Mixer
DEM
SMUTE
5 Band
DATT
DAC of Stereo
Equalizer
CODEC
DACM bit
Figure 25. DAC block diagram of Stereo CODEC
The AK4641 has the following functions for DAC of Stereo CODEC.
(1) 5 Band Equalizer
(2) Soft mute
(3) Digital Attenuator
(4) De-emphasis Filter (32kHz, 44.1kHz and 48kHz)
Mono Mixer
„ De-emphasis Filter
The AK4641 includes the digital de-emphasis filter (tc = 50/15µs) by IIR filter. Setting the DEM1-0 bits enables the
de-emphasis filter.
DEM1
0
0
1
1
DEM0
Mode
0
44.1kHz
1
OFF
0
48kHz
1
32kHz
Table 12. De-emphasis Control
Default
„ Digital Attenuator
The AK4641 has a channel-independent digital attenuator (256levels, 0.5dB step, Mute). The ATTL/R7-0 bits set the
attenuation level of each channel (Table 13). When the DATTC bit = “1”, the ATTL7-0 bits control both Lch and Rch
attenuation levels. When the DATTC bit = “0”, the ATTL7-0 bits control Lch level and ATTR7-0 bits control Rch level.
This attenuator has a soft transition function. It takes around 1061/fs (24ms@44.1kHz) at TM bit = “0” and 256/fs
(5.8ms@44.1kHz) at TM bit = “1” from 00H to FFH.
ATTL/R7-0
Attenuation
00H
0dB
Default
01H
−0.5dB
02H
−1.0dB
03H
−1.5dB
:
:
:
:
FDH
−126.5dB
FEH
−127.0dB
FFH
MUTE (−∞)
Table 13. DATT Code Table
MS0301-E-00
- 27 -
2004/05