AK4635 Datasheet, PDF (37/81 Pages) Asahi Kasei Microsystems – 16-Bit Mono CODEC with ALC & MIC/SPK/Video-AMP

[AK4635]
■ System Reset
When power-up, the PDN pin should be “L” and change to “H” after all power are supplied. “L” time of 150ns or more
is needed to reset in the AK4635.
The ADC enters an initialization cycle when the PMADC bit is changed from “0” to “1”. The initialization cycle time is
1059/fs, or 133ms@fs = 8kHz. 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) Off-set occurs in the initial data depending on the conditions of a microphone and cut-off frequency of HPF.
When Off-set becomes a problem, lengthen initialization time of ADC as 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 18 Initialization cycle of ADC
fs = 48kHz
22.1ms
6.1ms
■ Thermal Shut Down
When the internal device temperature rises up irregularly (e.g. output pins of speaker amplifier are shortened), the
AK4635 is powered down automatically and then THDET bit becomes “1”. The powered-down speaker amplifier do not
return to normal operation unless SPK-Amp blocks of the AK4635 are reset by the PDN pin “L”. The device status can be
monitored by THDET bit.
■ MIC/LINE Input Selector
The AK4646 has an input selector. When MDIF bit is “0”, LIN bit selects MIC pin or LIN pin. When MDIF bit is “1”,
full-differential input is available.
MDIF bit
0
0
1
LIN bit
Input circuit
Input pin
0
Single-End
MIC pin
1
Single-End
LIN pin
x
Differential
MICP/MICN pin
Table 19. Input Select (x: Don’t care)
(default)
MIC/MICP pin
AK4635
LIN/MICN pin
LIN bit
MDIF bit
ADC
Figure 36 Input Selector
Rev. 0.6
- 37 -
2007/10