ak5394a AKM Semiconductor, Inc., ak5394a Datasheet - Page 22

• Manufacturer Part Number: ak5394a
• Description: Super High Performance 192khz 24-bit ?? Adc
• Manufacturer: AKM Semiconductor, Inc.

ASAHI KASEI
6. Noise floor of AK5394A
The AK5394A has a sprious noise of about −135dBFS on the noise floor of Lch output at no signal input. When this noise
causes a trouble in system, it can be removed by adding a minute offset to the analog inputs of both channels externally
using a circuit as Figure 13. The relationship between the frequency range (f
adding offset voltage (V
A resistor, R in Figure 13 should be 8Ω to add an offset of 2mV to the analog inputs. The relationship between R and V
is shown by the following equation.
An offset voltage of the op-amps should be considered in the actual circuit. For example, when removing the sprious
noise of 20kHz or less, the adding offset voltage should be 2+2=4mV if the op-amp has an offset of +/−2mV. In this case,
the dynamic range of the ADC output decreases 4mV.
MS0137-E-03
10k
10k
R
5V
10
+
µ
0.1
of
Bias+
Bias-
µ
) is f
T
[kHz] = 20 x V
Table 10. Sprious noise Frequency vs. Offset voltage
Sprious noise Frequency
Vin+
Figure 13. Removing the sprious noise circuit
0 ∼ 20kHz
0 ∼ 40kHz
0 ∼ 80kHz
Vin-
of
V
68µ
68µ
XLR
[mV] − 20. The example is shown in Table 10.
of
=
Bias+
20
3.3k
3.3k
- 22 -
Bias-
k
R
+
NJM5534
NJM5534
R
+
-
-
+
×
620
620
1n
[ 5
1n
Offset Voltage
V
]
+2mV
+3mV
+5mV
91
91
T
) of the sprious noise to be removed and the
2.2n
AK5394A AIN-
AK5394A AIN+
[AK5394A]
2005/05
of