ASAHI KASEI
[AKD4356]
n External analog circuit
The 2nd order LPF (fc=93.2kHz, Q=0.712) which adds differential outputs of AK4356 is implemented on the board.
When the further attenuation of the out-band noise is needed, some additional LPF is required. Analog signal is output
through BNC connectors on the board. And the output level of AK4356 is 5.5Vpp@5V.
The AK4356 detects input signal “zero” conditions and assert high on DZFL/DZFR pins. As shown on Figure 2, analog
output is muted externally with this signal.
DZFL*
(DZFR*)
LOUT-
(ROUT-)
RN1202
JP*
DZFL*
(DZFR*) R2
R1
R3
C1
C2
+12V
AVDD
RN2202
2SC3327
LOUT-
(ROUT-)
R1
R3
R2
-
+
C2
22u
NJM5532D
-12V
220
10k
Figure 2. On-board analog filter
R1
R2
R3
C1
C2
4.7k
4.7k
200
3300p
470p
Table 1. The value of R,C on this board
fin
20kHz
40kHz
Frequency Response -0.004dB -0.123dB
Table 2. Frequency Response of LPF
80kHz
-1.823dB
<Calculation>
fC=
ω0
2π
,
ω0=
1
,
2*C1*C2*R2*R3
Q=
2*C1*ω0 .
1
R1
+
1
R2
+
1
R3
<KM060602>
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