AK4955 Datasheet, PDF (35/117 Pages) Asahi Kasei Microsystems – 24bit Stereo CODEC with MIC/SPK/Cap-less VIDEO-AMP/ LDO & DSP

[AK4955]
■ Mono/Stereo Mode
PMADL, PMADR, PMDML and PMDMR bits set mono/stereo ADC operation. When changing ADC operation and
analog/digital microphone, PMADL, PMADR, PMDML and PMDMR bits must be set “0” at first. When PMDML or
PMDMR bit = “1”, PMADL and PMADR bit settings are ignored.
PMADL bit
0
0
1
1
PMADR bit
ADC Lch data
ADC Rch data
0
All “0”
All “0”
1
Rch Input Signal
Rch Input Signal
0
Lch Input Signal
Lch Input Signal
1
Lch Input Signal
Rch Input Signal
Table 18. Mono/Stereo ADC operation (Analog MIC)
(default)
PMDML bit
0
0
1
1
PMDMR bit
ADC Lch data
ADC Rch data
0
All “0”
All “0”
1
Rch Input Signal
Rch Input Signal
0
Lch Input Signal
Lch Input Signal
1
Lch Input Signal
Rch Input Signal
Table 19. Mono/Stereo ADC operation (Digital MIC)
(default)
■ MIC/LINE Input Selector
The AK4955 has an input selector. INL and INR bits select LIN1/LIN2 and RIN1/RIN2, respectively. When DMIC bit =
“1”, digital microphone input is selected regardless of INL and INR bits.
DMIC bit
0
1
INL bit
INR bit
Lch
Rch
0
0
LIN1
RIN1
0
1
LIN1
RIN2
1
0
LIN2
RIN1
1
1
LIN2
RIN2
x
x
Digital Microphone
Table 20. MIC/Line In Path Select (x: Don’t care)
(default)
■ MIC Gain Amplifier
The AK4955 has a gain amplifier for microphone input. The gain of MIC-Amp is selected by the MGAIN3-0 bits (Table
21). The typical input impedance is 33kΩ.
MGAIN3 bit
0
0
0
0
0
0
0
0
1
MGAIN2 bit MGAIN1 bit MGAIN0 bit Input Gain
0
0
0
0dB
0
0
1
+5dB
0
1
0
+8dB
0
1
1
+11dB
1
0
0
+14dB
1
0
1
+16dB
1
1
0
+18dB
1
1
1
+21dB
0
0
0
+24dB
Others
N/A
Table 21. Input Gain (N/A: Not available)
(default)
MS1343-E-00
- 35 -
2011/12