AKD4621-B Datasheet, PDF (12/50 Pages) Asahi Kasei Microsystems – AK4621 Evaluation board Rev.2

[AKD4621-B]
„ Analog Input Buffer Circuit
The AK4621 can accept input voltages from AGND to AVDD. The input signal range scales with the VREF voltage and
is nominally 2.82Vpp (VREF = 5V). Figure 3 shows an input buffer circuit example. This is a fully differential input
buffer circuit with an inverted amplifier (fc=370KHz,gain: −10dB).
The capacitor of 10nF between AINL+/− (AINR+/−) decreases the clock feed through noise of the modulator, and
composes a 1st order LPF (fc=360kHz) with a 22Ω resistor before the capacitor.
Analog In
9.3Vpp
AVDD
10k
0.1μ 10μ
10k
910
4.7k
470p
4.7k
VP+ _{47μ 3k}
VP-
NJM5532
Bias
910
470p
47μ _3k
AVDD = 5V
Bias
VP+ = 15V
Bias
VP- = -15V
2.82Vpp
22
AIN+
10n
AK4621
22
AIN-
2.82Vpp
Figure 3. Input buffer circuit in differential input mode
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