|
AK4643 Datasheet, PDF (40/104 Pages) Asahi Kasei Microsystems – Stereo CODEC with MIC/HP/RCV/SPK-AMP | |||
|
◁ |
ASAHI KASEI
[AK4643]
 MIC Gain Amplifier
The AK4643 has a gain amplifier for microphone input. The gain of MIC-Amp is selected by the MGAIN1-0 bits (see
Table 23). The typical input impedance is 60kâ¦(typ)@MGAIN1-0 bits = â00â or 30kâ¦(typ)@MGAIN1-0 bits = â01â,
â10â or â11â.
 MIC Power
MGAIN1 bit
0
0
1
1
MGAIN0 bit Input Gain
0
0dB
1
+20dB
0
+26dB
1
+32dB
Table 23. Mic Input Gain
Default
When PMMP bit = â1â, the MPWR pin supplies power for the microphone. This output voltage is typically 0.75 x AVDD
and the load resistance is minimum 0.5kâ¦. In case of using two sets of stereo mic, the load resistance is minimum 2k⦠for
each channel. No capacitor must not be connected directly to MPWR pin (see Figure 34).
PMMP bit
MPWR pin
0
Hi-Z
1
Output
Table 24. MIC Power
Default
MIC Power
MPWR pin
LIN1 pin
RIN1 pin
LIN2 pin
RIN2 pin
Figure 34. MIC Block Circuit
Microphone
Microphone
Microphone
Microphone
MS0476-E-01
- 40 -
2006/10
|
▷ |