ak4642e AKM Semiconductor, Inc., ak4642e Datasheet - Page 32

• Manufacturer Part Number: ak4642e
• Description: Stereo Codec With Mic/hp/spk-amp
• Manufacturer: AKM Semiconductor, Inc.

ASAHI KASEI
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”.
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).
MS0420-E-00
MIC Gain Amplifier
MIC Power
Figure 21. Connection Example for Full-differential Mic Input (MDIF1/2 bits = “1”)
MIC Power
MGAIN1 bit
0
0
1
1
PMMP bit
1k
1k
0
1
Figure 22. MIC Block Circuit
MGAIN0 bit
MPWR pin
Table 16. Mic Input Gain
IN1+ pin
Table 17. MIC Power
IN1− pin
MPWR pin
LIN1 pin
RIN1 pin
LIN2 pin
RIN2 pin
0
1
0
1
- 32 -
MPWR pin
Output
Hi-Z
Input Gain
+20dB
+26dB
+32dB
0dB
MIC-Amp
Default
AK4642
Default
Microphone
Microphone
Microphone
Microphone
[AK4642EN]
2005/09