AK5385AVS Datasheet, PDF (19/24 Pages) Asahi Kasei Microsystems – 24Bit 192kHz DS ADC

ASAHI KASEI
[AK5385A]
4. External Analog Circuit Examples
Figure 6 shows an input buffer circuit example 1. This is a full-differential input buffer circuit with an inverted-amp (gain:
−10dB). The capacitor of 10nF between LIN+/− (RIN+/−) decreases the clock feed through noise of modulator, and
composes a 1st order LPF (fc=360kHz) with 22Ω resistor before the capacitor. This circuit also has a 1st order LPF
(fc=370kHz) composed of op-amp. The evaluation board should be referred about the detail.
Analog In
9.56Vpp
VA
10k _{0.1µ 10µ}
10k
910
4.7k
470p
4.7k
VP+ _{47µ 3k}
VP-
NJM5532
Bias
910
470p
47µ _3k
VA = 5V
Bias
VP+ = 15V
Bias
VP- = -15V
2.9Vpp
22
4 LIN+
10n
AK5385A
22
5 LIN-
2.9Vpp
Figure 6.Input Buffer example
Figure 7 shows an input buffer circuit example 2. (1^st order HPF: fc=0.66Hz, Table 6; 1^st order LPF: fc=590kHz,
gain=−14dB, Table 7). The analog signal is able to input through XLR or BNC connectors. (short JP1 and JP2 for BNC
input, open JP1 and JP2 for XLR input). The input level of this circuit is +/−14.7Vpp.
BNC
4.7k
14.7Vpp
JP1
Vin+
22µ
1k
XLR
4.7k
JP2
VA
NJM5534
10k
0.1µ ^4.7k
Bias
10µ
4.7k
10k
NJM5534
Vin-
22µ
1k
14.7Vpp
NJM5534
2.9Vpp
91
4 LIN+
AK5385A
1.5n
100
91
2.9Vpp
5 LIN-
Figure 7.Input Buffer example
fin
1Hz
10Hz
Frequency Response −1.56dB −0.02dB
Table 6. Frequency Response of HPF
fin
20kHz
40kHz 6.144MHz
Frequency Response −0.005dB −0.02dB −15.6dB
Table 7. Frequency Response of LPF
MS0265-E-01
- 19 -
2003/11