AK7755EN_16 Datasheet, PDF (86/109 Pages) Asahi Kasei Microsystems – DSP with Mono ADC Stereo CODEC + Mic/Lineout Amp

[AK7755]
4. LINE Input Gain Amplifier
The AK7755 has a gain amplifier for line inputs. It is enabled by setting PMLI bit (CONT0F: D5) =
“1”, and it outputs a signal to the L channel of the ADC2. LIGN[3:0] bits (CONT13: D7-D4) controls
the gain. The typical input impedance is 20k (typ). A pop noise occurs if the input gain is changed
during operation.
The AK7755 becomes digital microphone interface mode when DMIC2 bit (CONT1E: D4) = “1”.
Digital microphone input data to the DMDAT2 pin is input to the Lch/Rch of the ADC2.
ADC2 Input Setting
DMIC2 bit ADC2 Lch Input
0
LIN
1
Digital Microphone
ADC2 Rch Input
No
Digital Microphone
(default)
Mode
0
1
2
3
4
5
6
7
8
9
A
B
C
D
E
F
LIGN[3]
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
LIGN[2] LIGN[1] LIGN[0]
0
0
0
0
0
1
0
1
0
0
1
1
1
0
0
1
0
1
1
1
0
1
1
1
0
0
0
0
0
1
0
1
0
0
1
1
1
0
0
1
0
1
1
1
0
1
1
1
Table 3. Line Input Gain
Input Gain
0dB
-3dB
-6dB
-9dB
-12dB
-15dB
-18dB
-21dB
N/A
+3dB
+6dB
+9dB
+12dB
+15dB
+18dB
+21dB
(default)
014006643-E-00
- 86 -
2014/10