AK5554 Datasheet, PDF (65/68 Pages) Asahi Kasei Microsystems – 4-Channel Differential 32-bit ADC

[AK5554]
4. External Analog Circuit Examples
Figure 73 shows an input buffer circuit example 1. (1^st order HPF; fc= 0.70 Hz, 2^nd order LPF; fc= 351
kHz, gain= 14.5 dB). 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 14.9 Vpp (AK5554:
2.8 Vpp Typ.). When using this circuit, analog characteristics at fs= 48 kHz is DR= 115 dB, S/(N+D)= 106
dB. The S/(N+D) characteristics of the AK5554 varies depending on DC bias current of the input signal.
Set the DC bias voltage in a range from 0.49 x AVDD to 0.51 x AVDD for a better characteristic.
* Film capacitors are recommended for the components shown as 15nF and 1 nF in the figure below.
4.7k
4.7k ^VP+
Analog In
-
14.9Vpp
+
VP-
NJM5534
620
JP1
1n *
Vin- ^68µ 3.3k
10
-
+
Bias
NJM5534
VA+
10k
+
10k
10µ
XLR
620
Bias
JP2
0.1µ
VA=+5V
Vin+
VP=15V
1n *
68µ _3.3k
-
10
+
NJM5534
Bias
Figure 73. Input Buffer Example1
2.8Vpp
AK5554 AINn+
100p
15n *
100p
AK5554 AINn-
2.8Vpp
fin
1Hz
10Hz
Frequency Response 1.77dB 0.02dB
Table 23. Frequency Response of HPF
fin
20kHz 40kHz 80kHz
Frequency Response 0.00dB 0.00dB 0.00dB
Table 24. Frequency Response of LPF
6.144MHz
49.68dB
015099864-E-00
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2016/03