AK4642EN Datasheet, PDF (32/83 Pages) Asahi Kasei Microsystems – Stereo CODEC with MIC/HP/SPK-AMP

ASAHI KASEI
[AK4642EN]
MPWR pin
1k
IN1− pin
IN1+ pin
1k
AK4642
MIC-Amp
Figure 21. Connection Example for Full-differential Mic Input (MDIF1/2 bits = “1”)
„ MIC Gain Amplifier
The AK4642 has a gain amplifier for microphone input. The gain of MIC-Amp is selected by the MGAIN1-0 bits (see
Table 16). The typical input impedance is 60kΩ(typ)@MGAIN1-0 bits = “00” or 30kΩ(typ)@MGAIN1-0 bits = “01”,
“10” or “11”.
„ MIC Power
MGAIN1 bit
0
0
1
1
MGAIN0 bit Input Gain
0
0dB
1
+20dB
0
+26dB
1
+32dB
Table 16. Mic Input Gain
Default
When PMMP bit = “1”, the MPWR pin supplies power for the microphone. This output voltage is typically 0.75 x AVDD
and the load resistance is minimum 0.5kΩ. In case of using two sets of stereo mic, the load resistance is minimum 2kΩ for
each channel. No capacitor must not be connected directly to MPWR pin (see Figure 22).
PMMP bit
MPWR pin
0
Hi-Z
1
Output
Table 17. MIC Power
Default
MIC Power
MPWR pin
MS0420-E-00
LIN1 pin
RIN1 pin
LIN2 pin
RIN2 pin
Figure 22. MIC Block Circuit
Microphone
Microphone
Microphone
Microphone
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2005/09