ak4633 AKM Semiconductor, Inc., ak4633 Datasheet - Page 37

• Manufacturer Part Number: ak4633
• Description: 16-bit ?? Mono Codec With Alc & Mic/spk-amp
• Manufacturer: AKM Semiconductor, Inc.

ASAHI KASEI
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 that starts 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 compliment, “0”. The ADC output reflects the analog input signal after the initialization cycle is
complete. 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
The AK4633 has a Gain Amplifier for Microphone input. This gain is selected by MGAIN2-0 bits. The typical input
impedance is 30kΩ.
MS0447-E-03
System Reset
MIC Gain Amplifier
frequency of HPF. If this offset isn’t small, the longer initialization cycle should be selected as ADRSTbit=“0” in
order to prevent the offset data. Or, do not use the initial data of ADC.
ADRST bit
0
1
MGAIN2 bit
0
0
0
0
1
1
1
1
1059/fs
MGAIN1 bit
291/fs
Cycle
Table 17. Initialization cycle of ADC
0
0
1
1
0
0
1
1
Table 18. Input Gain
MGAIN0 bit
fs = 8kHz
132.4ms
- 37 -
36.4ms
0
1
0
1
0
1
0
1
Init Cycle
Input Gain
+20dB
+26dB
+32dB
+10dB
+14dB
+17dB
fs = 16kHz
+6dB
0dB
66.2ms
18.2ms
Default
fs = 48kHz
22.1ms
6.1ms
[AK4633]
2006/04