AKD4359-SC Datasheet, PDF (4/33 Pages) Asahi Kasei Microsystems – the 24bit 8ch D/A converter.

ASAHI KASEI
[AKD4359-SC]
„ External analog circuit
The 2nd order LPF (fc=111.8kHz, Q=0.714) which adds differential outputs of the AK4359 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 the AK4359 is 5.68Vpp@5V.
22u
R1
AOUT
10k
C1
R4
R3
+Vop
R2
C2
-Vop
Analog
Out
fc=111.8kHz, Q=0.714, g=-0.04dB at 40kHz
Figure 4. On-board analog filter
R₁
R₂
R₃
R₄
C₁
C₂
1.5k
1.8k
2.2k
3.3k
820p
820p
Table 5. The value of R,C on this board
fin
20kHz
40kHz
Frequency Response
0.00dB -0.04dB
Table 6. Frequency Response of LPF
80kHz
-0.76dB
<Calculation>
Amplitude = 20 log
K
[dB],
[1-(f/fc)²] ²+[(1/Q)(f/fc)] ²
K=
R₃+R₄
R₄
,
fc=
ω₀
2π
,
ω₀=
1
,
2C₁C₂R₁R₂
Q = 2πfc
1
+
1
1
+ ^1−k
C₁R₁ C₁R₂ C₂ R₂
<KM079600>
-4-
2005/06