AK4687 AKM [Asahi Kasei Microsystems], AK4687 Datasheet - Page 19

• Manufacturer Part Number: AK4687
• Description: Asynchronous Stereo CODEC with Capless Stereo Selector
• Manufacturer: AKM [Asahi Kasei Microsystems]

■
The AK4687 has 3:1 stereo input selectors. AIN1-0 bits control each input channel in I
control each selector in H/W control mode.
■
The input attenuation circuit is constructed by connecting input resistors (Ri) to LIN1-3/RIN1-3 pins and feedback
resistors (Rf) between LI/RI pin and LO/RO pin
1.91Vrms. Therefore, excessive inputs such as 2Vrms or 4Vrms to the LIN1-3/RIN1-3 pins via Ri resistors must be
attenuated to 1.91Vrms by these Ri and Rf resistors.
MS1307-E-00
Pre-Amp and Input ATT
Input Selector
Input Range
2.2Vrms
4Vrms
1Vrms
AIN1 pin
AIN1 bit
Ri (kΩ)
Ri
Ri
Ri
H
H
L
0
0
1
1
47
47
47
L
Table 20. ADC Input Selector (H/W Control Mode)
Table 19. ADC Input Selector (I
LIN1
LIN2
LIN3
Rf (kΩ)
Figure 7. Pre-Amp and Input ATT
(Table
20
39
82
Table 21. Input ATT example
(Figure
AIN0 pin
19)
AIN0 bit
LI
Table 21
H
H
L
L
0
1
0
1
7). The input voltage tolerance of the LO/RO pin is typically
ATT Gain (dB)
- 19 -
+4.83
Pre-Amp
-7.42
-1.62
shows resistance examples of Ri and Rf.
Rf
2
C Control Mode)
Input Selector
Input Selector
LIN1 / RIN1
LIN2 / RIN2
LIN3 / RIN3
LIN1 / RIN1
LIN2 / RIN2
LIN3 / RIN3
Reserved
Reserved
LO
LO/RO pin
1.70Vrms
1.82Vrms
1.74Vrms
2
C control mode, and AIN1/0 pins
(default)
ADC output (typ)
-0.39dBFS
-0.78dBFS
-1.0dBFS
[AK4687]
2011/05