AK4633EN Datasheet, PDF (37/83 Pages) Asahi Kasei Microsystems – 16-Bit Mono CODEC with ALC & MIC/SPK-AMP

[AK4633]
■ System Reset
Upon power-up, reset the AK4633 by bringing the PDN pin = “L”. This ensures that all internal registers reset to their
initial values.
The ADC enters an initialization cycle when the PMADC bit is changed from “0” to “1”. The initialization cycle time is
selected by ADRST bit (Table 17). During the initialization cycle, the ADC digital data outputs of both channels are
forced to a 2's complement, “0”. The ADC output reflects the analog input signal after the initialization cycle is completed.
The DAC does not require an initialization cycle.
(Note) The initial data of ADC has the offset data that depends on the condition of the microphone and the cut-off
frequency of HPF. When Off-set becomes a problem, lengthen initialization time of ADC by ADRST bit = “0” or
do not use initial output data of ADC.
ADRST bit
0
1
Init Cycle
Cycle
fs = 8kHz
fs = 16kHz
1059/fs
132.4ms
66.2ms
291/fs
36.4ms
18.2ms
Table 17. Initialization cycle of ADC
fs = 48kHz
22.1ms
6.1ms
■ MIC Gain Amplifier
The AK4633 has a Gain Amplifier for Microphone input. This gain is selected by MGAIN2-0 bits. The typical input
impedance is 30k.
MGAIN2 bit
0
0
0
0
1
1
1
1
MGAIN1 bit MGAIN0 bit Input Gain
0
0
0dB
0
1
+20dB
1
0
+26dB
1
1
+32dB
0
0
+6dB
0
1
+10dB
1
0
+14dB
1
1
+17dB
Table 18. Input Gain
(default)
MS0447-E-06
- 37 -
2015/10