ak4620b AKM Semiconductor, Inc., ak4620b Datasheet - Page 36

• Manufacturer Part Number: ak4620b
• Description: 24-bit 192khz Audio Codec With Ipga
• Manufacturer: AKM Semiconductor, Inc.

ASAHI KASEI
1. Grounding and Power Supply Decoupling
The AK4620B requires careful attention to power supply and grounding layout. To minimize coupling from digital noise,
decoupling capacitors should be connected to VA, VD and VT respectively. VA is supplied from the analog supply in the
system, and VD and VT are supplied from the digital supply in the system. Power lines of VA, VD and VT should be
distributed separately from the point with low impedance of regulator etc. The power up sequence is not critical among
VA, VD and VT. AGND and DGND must be connected to one analog ground plane. Decoupling capacitors
should be as near to the AK4620B as possible, with the small value ceramic capacitor being the nearest.
2. Voltage Reference
The differential voltage between VREF and AGND sets the analog input/output range. VREF pin is normally connected
to VA with a 0.1µF ceramic capacitor. VCOM is the signal ground of this chip. A 10µF electrolytic capacitor in parallel
with a 0.1µF ceramic capacitor attached to VCOM pin eliminates the effects of high frequency noise. No load current may
be drawn from VCOM pin. All signals, especially clocks, should be kept away from the VREF and VCOM pins in order
to avoid unwanted coupling into the AK4620B.
3. ADC Output
The ADC output data format is 2’s complement. The DC offset, including the ADC’s own DC offset, is removed by the
internal HPF. The AK4620B samples the analog inputs at 128fs. The digital filter rejects noise above the stopband except
for multiples of 128fs.
MS0401-E-00
Digital Ground
Controller
System
Figure 16. Ground Layout
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Analog Ground
10
11
12
13
14
15
1
2
3
4
5
6
7
8
9
VCOM
AINR+
AINR-/NC
AINL+
AINL-/NC
VREF
AGND
VA
P/S
MCLK
LRCK
BICK
SDTO
SDTI
OVFR/DZFR
AK4620B
CCLK/CKS1
OVFL/DZFL
CDTI/CKS0
ADMODE
AOUTR+
CSN/DIF
AOUTL+
AOUTR-
AOUTL-
DGND
DEM0
DFS0
PDN
VD
VT
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
[AK4620B]
2005/07