AKD4384-SC Datasheet, PDF (5/32 Pages) Asahi Kasei Microsystems – 192kHz sampling 24Bit ΔΣ DAC

[AKD4384-SC]
 External Analog Filter Circuit
The 2nd order LPF (fc=111.8kHz, Q=0.714) 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 AK4384 is
5.68Vpp@5V.
C1
R4
R3
22u
R1
AOUT
10k
+Vop
R2
C2
-Vop
Analog
Out
fc=111.8kHz, Q=0.714, g=-0.04dB at 40kHz
Figure 4. External 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
,
C₁C₂R₁R₂
Q = 2πfc
1
+
1
1
+ ^{1− k}
C₁R₁ C₁R₂ C₂ R₂
<KM079003>
5
2007/06