ak5702 AKM Semiconductor, Inc., ak5702 Datasheet - Page 39

• Manufacturer Part Number: ak5702
• Description: 4-channel Adc With Pll & Mic-amp
• Manufacturer: AKM Semiconductor, Inc.

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The AK5702 has a gain amplifier for microphone input. The gain of MIC-Amp is selected by the MGAINA1-0,
MGAINB1-0 bits (Table 25). The typical input impedance of LIN1-4 and RIN1-4 is 60kΩ(typ)@MGAINA1-0,
MGAINB1-0 bits = “00” or 30kΩ(typ)@MGAIN1-0 bits = “01”, “10” or “11”. Refer to Table 24 about the typical input
resistance of LIN5, RIN5.
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When PMMPA, PMMPB bits = “1”, the MPWRA, MPWRB pins 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 MPWRA, MPWRB pins (
Figure 41, Figure 42).
MS0623-E-00
MGAINA1-0 bits
MIC Gain Amplifier
MIC Power
Don’t care
Don’t care
01,10,11
01,10,11
01,10,11
00
00
00
Figure 40. Connection Example for Full-differential Mic Input (MDIFA1/2 bits = “1”)
MGAINB1-0 bits
MGAINA/B1 bit
Don’t care
Don’t care
01,10,11
01,10,11
01,10,11
00
00
00
0
0
1
1
PMMPA/B bit
Table 24. Input Resistance of LIN5, RIN5
0
1
1k
1k
LIN1-2/RIN1-2
LIN1-2/RIN1-2
MPWRA pin
MGAINA/B0 bit
ADCA Input
Table 25. Mic Input Gain
LIN5/RIN5
LIN5/RIN5
LIN5/RIN5
LIN5/RIN5
LIN5/RIN5
LIN5/RIN5
IN1+ pin
IN1− pin
Table 26. MIC Power
0
1
0
1
MPWRA/B pin
- 39 -
Output
Hi-Z
MIC-Amp
Input Gain
LIN3-4/RIN3-4
LIN3-4/RIN3-4
ADCB Input
+15dB
+30dB
+36dB
LIN5/RIN5
LIN5/RIN5
LIN5/RIN5
LIN5/RIN5
LIN5/RIN5
LIN5/RIN5
0dB
(default)
AK5702
(default)
Input Resistance (typ)
30kΩ
20kΩ
15kΩ
[AK5702]
2007/06