
[AK4671] 
MS0666-E-00 
2007/10 
- 159 - 
■
 MIC Input Phone Call (Mono) 
MIC Control 2
(Addr:05H, D3-0)
PMMICL bit
PMADL bit
(Addr:00H, D4&D2)
ADC Internal
State
0101
1010
Power Down
Initialize Normal State
Power Down
1059 / fs
(6)
(4)
HPF bit
(Addr:1DH, D4)
0
1
EQ bit
(Addr:18H, D3)
0
1
(7)
PMSRA bit
(Addr:53H, D0)
MIC Control 1
(Addr:04H, D7-0)
00H
14H
(1)
PMMP bit
(Addr:00H, D1)
HPFAD bit
(Addr:1DH, D1)
0
1
(2)
(5)
IVL7-0 bits
(Addr:12H, D7-0)
91H
BFH
0
(9)
(8)
PFMXL1-0 bits
(Addr:15H, D1-0)
00
01
(3)
Example:
PCM I/F A: Slave Mode 
PCM I/F A Format: Linear, Short Frame (ADC & DAC)
Sampling Frequency: 8kHz 
Pre MIC AMP: +15dB  
MIC Power: On  
Digital Volume Level: +17.25dB  
ADC HPF: Enable  
5 band EQ: Enable  
(1) Addr:04H, Data:14H 
Addr:05H, Data: AAH 
(4) Addr:18H, Data:0AH 
(5) Addr:12H, Data:BFH 
(6) Addr:00H, Data:17H 
  Addr:53H, Data:05H  
Phone Call  
(7) Addr:00H, Data:01H 
Addr:53H, Data:04H  
(2) Addr:1DH, Data:12H 
(9) Addr:18H, Data:02H 
(8) Addr:1DH, Data:00H 
(3) Addr:15H, Data:01H 
Figure 124
. Mono MIC Input Sequence 
(Phone Call Tx: IN1+/IN1- 
→
 MICL 
→
 ADCL 
→
 HPF
→
 IVL 
→
 EQ  
→
 SRC-A 
→
 PCM I/F A 
→
 SDTOA) 
<Example> 
At first, clocks should be supplied according to “
Clock Set Up
” sequence. Also, MIC, ADC and SRC-A should be 
powered-up in consideration of PLLBT lock time. 
(1)
Set up Signal Select for MIC Input (Addr: 04H) and Gain for MIC-Amp (Addr: 05H) 
(2)
Enable ADC High Pass Filter: HPFAD bit = “0” 
 “1” 
Enable the coefficient of High Pass Filter: HPF bit = “0” 
 “1” (Coefficient of wind-noise reduction filter is set by 
Addr = 28H- 2BH.) 
This sequence is an example of HPF setting at fs2=8kHz. The coefficient should be set when HPFAD = HPF bits = “0” 
or PMADL = PMADR = PMDAL = PMDAR bits = “0”. 
(3)
Set up the path of “ADC 
 5-band EQ”: PFMXL1-0 bits = “00” 
 “01” 
(4)
Enable 5-band Equalizer: EQ bit = “0” 
 “1” (Boost amount is selected by Addr = 50H-52H.) 
(5)
Set up input volume (Addr: 12H) 
When PMADL = PMADR bits = “0”, IVL7-0 and IVR7-0 bits should be set to “91H”(0dB). 
(6)
Power Up MIC, ADC and SRC-A: PMMP = PMMICL = PMADL = PMSRA bits = “0” 
→
 “1” 
The initialization cycle time of ADC is 1059/fs2=132ms@fs2=8kHz. 
The time of offset voltage going to “0” after the ADC initialization cycle depends on both the time of analog input pin 
going to the common voltage and the time constant of the offset cancel digital HPF. This time can be shorter by using 
the following sequence:  
At first, PMVCM and PMMP bits should set to “1”. Then, the ADC should be powered-up. The wait time to power-up 
the ADC should be longer than 4 times of the time constant that is determined by the AC coupling capacitor at analog 
input pin and the internal input resistance. 
(7)
Power Down MIC, ADC and SRC-A: PMMP = PMMICL = PMADL = PMSRA bits = “1” 
→
 “0” 
IVOL gain is not reset when PMADL = PMADR bits = “0”, and then IVOL operation starts from the setting value when 
PMADL or PMADR bit is changed to “1”. 
(8)
Disable ADC High Pass Filter : HPFAD bit = “1” 
 “0” 
Disable the coefficient of High Pass Filter: HPF bit = “1” 
 “0” 
(9)
Disable 5-band Equalizer: EQ bit = “1” 
 “0”