AK5374 Datasheet, PDF (14/51 Pages) Asahi Kasei Microsystems – 24-bit Stereo ADC with USB Interface

[AK5374]
■ MIC Gain Amplifier
The AK5374 has a gain amplifier for microphone inputs. The gain of MIC-Amp is selected by the MGAIN2-0 bits (Table
2).
MGAIN2 MGAIN1 MGAIN0
bit
bit
bit
Input Gain
0
0
0
0dB
0
0
1
0dB
0
1
0
+6dB
0
1
1
+12dB
1
0
0
+18dB
1
0
1
+24dB
1
1
0
+30dB
1
1
1
+36dB
Table 2. Mic Input Gain (x: Don’t care)
■ MIC Power
When PMMP bit = “1”, the MPWR pin supplies power for the microphone. This output voltage is typically 2.2V and the
output current is maximum 2.0mA. In case of using two sets of stereo full-differential microphones, the load resistance is
minimum 1kΩ for each channel. Any capacitor must not be connected directly to the MPWR pin (Figure 12).
PMMP bit
MPWR pin
0
Hi-Z
1
Output
Table 3. MIC Power
MIC Power
VREF
MPWR
AK5374
MI CLP
MI CLN
MI CRP
MI CRN
Mi crop hone
Mi crop hone
Figure 12. MIC Block Circuit
MS1197-E-00
- 14 -
2010/05