AK4601VQ Datasheet, PDF (106/111 Pages) Asahi Kasei Microsystems – Audio HUB CODEC with Digital Mixer

[AK4601]
■ Peripheral Circuit
1. Ground
AVSS, DVSS1 and DVSS2 should be connected to the same ground. Decoupling capacitors, particularly
capacitors of small capacity, should be placed at positions as close as possible to the AK4601.
2. Reference Voltage
The AVDD voltage controls analog signal range. VCOM is a common voltage of this chip and the VCOM
pin outputs AVDD/2. A 2.2µF capacitor should be connected between the VCOM pin and AVSS.
Do not connect the VCOM pin to any external devices. Digital signal lines, especially clock signal line
should be kept away as far as possible from this pin in order to avoid unwanted coupling into the AK4601.
3. Analog Input
The analog input signal is input to the analog modulator of the AK4601. When AVDD = 3.3V and AVSS =
0.0V, the input voltage range at differential input pin is ±2.30Vpp or ±2.83Vpp (Typ.) and 2.30Vpp or
2.83Vpp (Typ.) at single-ended input pin. The output code format is 2's complements. The internal HPF
removes the DC offset.
After power-down is released, the internal operating point level AVDD/2 occurs on analog input pins of the
AK4601. Concerning the internal operating point formation circuit, each input pin has impedance of 25k
(typ). The pins that are connected to AC coupling capacitors require start-up time (time constant).
The AK4601 samples the analog inputs at 6.144MHz when fs=48kHz. Digital filters remove noise around
from 30kHz to 6.114MHz. The AK4601 includes an anti-aliasing filter (RC filter). This filter attenuates
noises around 6.114MHz ~ 6.144MHz, which are not removed by the digital filters. Therefore no external
low-pass filter is needed in front of the ADC since most of audio signals do not have a large noise around
6.114MHz. However, an external low-pass filter should be connected before the ADC for the signal which
has large out-of-band noise such as D/A converted signals.
The analog power supply to the AK4601 is +3.3V typical. Voltage of AVDD + 0.3V or larger, voltage of
AVSS - 0.3V or smaller, and current of 10mA or larger must not be applied to analog input pins. Excessive
current will damage the internal protection circuit and will cause latch-up, damaging the IC. Accordingly, if
the external analog circuit voltage is ±15V, the analog input pins must be protected from signals which are
equal or larger than absolute maximum ratings.
10k
22u
68p
Signal
+ ^10k
+10V
-
10k
+ _-10V
10k
68p
-
+
2.30Vpp / 2.83Vpp
+
INP*
1u
+
INN*
1u
2.30Vpp / 2.83Vpp
Figure 75. Input Buffer Circuit Example at fs=48kHz (Differential Input)
016000391-E-01
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2016/12