[AK4675]
■ MIC Gain Amplifier
The AK4675 has a gain amplifier for microphone input. The gain of MIC-Amp Lch and Rch is independently selected by
the MGNL3-0 and MGNR3-0 bits (Table 19). The typical input impedance is 42kΩ(typ)@MGNL/R0 bits = “0” or
30kΩ(typ)@MGNL/R0 bits = “1”.
MGNL3
MGNR3
MGNL2
MGNR2
MGNL1
MGNR1
MGNL0
MGNR0
Mode
Input Gain
Input Resistance
0
1
2
3
4
5
6
7
8
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
0
0
0
0
1
1
1
1
0
0
0
0
1
1
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
0
1
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
0
1
N/A
−12dB
−9dB
−6dB
−3dB
N/A
30kΩ
42kΩ
30kΩ
42kΩ
30kΩ
42kΩ
30kΩ
42kΩ
30kΩ
42kΩ
30kΩ
42kΩ
30kΩ
42kΩ
30kΩ
0dB
(default)
+3dB
+6dB
+9dB
+12dB
+15dB
+18dB
+21dB
+24dB
+27dB
+30dB
9
10
11
12
13
14
15
Table 19. Mic Input Gain
MS0963-E-00
2008/05
- 67 -
AKM [ ASAHI KASEI MICROSYSTEMS ]
