[AK4685]
■ Pre-Amp and Differential Inputs
The input ATTs are constructed by connecting input resistors (Ri) to LIN1+/- pins and feedback resistors (Rf) between
LAMPO1/ LVCOM1 pin and LIN1-/LIN1+ pin (Figure 10). The input voltage range of the LAMPO1/ LVCOM1 pin is
typically +/- 0.33 x AVDD (Vpp). If the input voltage of the input selector exceeds typ. +/- 5.66Vpp (+/- 2Vrms
differential), or +/-8.48Vpp(+/- 3Vrms differential), the input voltage of the LAMPO1/ LVCOM1 pins must be attenuated
to typ. +/-3.3 x AVDD1/5 (Vpp) ATTs. Table 17 shows Ri and Rf constant examples.
Rf
LAMPO1
Pr e- Amp
AINL1-
LIN1-
-
Ri
Ri
LIN1+
+
AINL1+
LVCOM1
Rf
Figure 10. External Connection Example (differential input)
Voltage between LAMPO1
Input Range
ATT Gain [dB]
–8.3
Ri [kΩ]
47
Rf [kΩ]
18
and LVCOM1 pins
+/-8.48Vpp
(+/-3Vrms Differential Input)
+/-5.66Vpp
(+/-2Vrms Differential Input)
+/-2.83Vpp
(+/-1Vrms Differential Input)
+/-3.25Vpp
33
18
–5.3
+/-3.08Vpp
+/-3.18Vpp
16
18
+1.02
Note 30. The input range of the internal ADC is +/-3.3 x AVDD1/5 Vpp typ.
Note 31. The input range is the voltage difference of Ri inputs (AINL1/L2/R1/R2+)-(AINL1/L2/R1/R2-).
Table 17. Input ATT Example (differential input)
MS1106-E-00
2009/08
- 26 -
AKM [ ASAHI KASEI MICROSYSTEMS ]
