AK4691 Datasheet, PDF (32/80 Pages) Asahi Kasei Microsystems – 4ch ADC + 2ch DAC with MIC/HP/SPK-AMP

[AK4691]
■ MIC Sensitivity Compensation
The AK4691 has MIC sensitivity (Interchannel gain mismatch) compensation function. The gain of each channel for
compensation is set by the resister as shown in Table 17. This function is enabled when Pre-Amp gain is from +18dB to
+32.4dB. It is ignored when Pre-Amp gain is 0dB or -4.4dB.
Register
Input pin
MGL12-10 bits
INTL1/EXTL1
MGR12-10 bits
INTR1/EXTR1
MGL22-20 bits
INTL2/EXTL2
MGR22-20 bits
INTR2/EXTR2
Table 17. Relationship between register and input pin
MGL12 bit MGL11 bit MGL10 bit
MGR12 bit MGR11 bit
MGL22 bit MGL21 bit
MGR10 bit
MGL20 bit
Gain
MGR22 bit MGR21 bit MGR20 bit
0
0
0
+2dB
0
0
1
+1dB
0
1
0
0dB
(default)
0
1
1
-1dB
1
0
0
-2dB
1
0
1
1
1
0
N/A
1
1
1
Table 18. MIC Sensitivity Compensation function (N/A: Not available)
■ Analog Mixing Circuit for Recording Block
Analog
Signal
6.2kΩ
LIN pin
(RIN pin)
6.2kΩ
typ.60kΩ /100kΩ
typ.100kΩ
AIN bit
typ. 60kΩ
From Pre-Amp1
PRE bit
-
+
MIXL-Amp
(MIXR-Amp)
To ADC1
Figure 23. Analog Mixing Circuit for Recording Block
1. LINE Input
Input resistance of LIN and RIN pins are typically 100kΩ and centered around the VCOM voltage. When the input
voltage exceeds +2dBV, the input signals should be attenuated down to –3.7dBV at AVDD=3.0V by external resistor
divider.
When AIN bit is “1”, LIN and RIN pins are selected. The MIX-Amp gain is changed by FB bit.
FB bit
Gain
0
-4.4dB
(default)
1
0dB
Table 19. MIX-Amp gain at LINE Input
MS0672-E-00
- 32 -
2007/11