AK4641 Datasheet, PDF (22/51 Pages) Asahi Kasei Microsystems – 16 BIT CODEC WITH BLUETOOTH INTERFACE

ASAHI KASEI
[AK4641]
„ MIC Input
DAC of
Mono CODEC
MICL bit
ATT
Stereo Mixer
MICM bit
ATT
Mono Mixer
Mic In
IPGA with ALC
MICAD bit
ADC of Stereo
CODEC
µP
0dB/+20dB
DAC2 bit = “0”: Mic Input Signal
“1”: DAC Signal
AUX IN
AUXAD bit
Figure 21. Microphone Input
The AK4641 has the following functions for Mic Input.
(1) 1^st MIC Amplifier of 20dB gain that can be selected ON/OFF by “MGAIN” bit.
(2) 2^nd Amplifier that has PGA with ALC. This volume is controlled by “IPGA6-0” bit as Table 7.
While ALC is working, Master Clock must be present.
When Master Clock is not provided or PMMIC bit = “0”, it is invalid to write to “IPGA6-0”.
(3) Attenuator for stereo mixer. This volume is controlled by “ATTS2-0” bit as Table 8.
(4) Attenuator for mono mixer. This attenuator level is 4dB and this ON/OFF is controlled by “ATTM” bit.
IPGA6-0
GAIN (dB)
STEP
47H
+27.5
46H
+27.0
45H
+26.5
:
:
36H
+19.0
:
:
10H
+0.0
:
:
0.5dB
06H
−5.0
05H
−5.5
04H
−6.0
03H
−6.5
02H
−7.0
01H
−7.5
00H
−8.0
Table 7. Microphone Input Gain Setting
Default
ATTS2-0
Attenuation
7H
−6dB
6H
−9dB
5H
−12dB
Default
4H
−15dB
3H
−18dB
2H
−21dB
1H
−24dB
0H
−27dB
Table 8. Attenuator Table
MS0301-E-00
- 22 -
2004/05