AK4532_04 Datasheet, PDF (14/17 Pages) Asahi Kasei Microsystems – Internet/Network/General Purpose Multimedia Audio CODEC

ASAHI KASEI
[AK4532]
System Design
Figure 2 shows the system connection diagram. An evaluation board is available which demonstrates the
optimum layout, power supply arrangements and measurement results.
4.7u ^{+ 0.1u}
10
14
VD
0.1u
2
VA
21
VRAD
+ _4.7u
+
4.7u
0.1u
+5V
Analog
Controller
&
Synth.
7
PD
VCOM ²⁴
8 _MCLK
9
LRCK
10
SCLK
AINFL ²²
11
SDI
12 _SDO
AK4532
AINFR ²³
18 _CMODE
17 _CDATA
16 _CCLK
15
CS
MIC/AUXR ³
AUXL ⁴
LineR ⁵
LineL ⁶
+
4.7u
0.1u
19
LOUT
Lch
Analog
Out
DGND
13
ROUT ²⁰
AGND
1
Rch
Analog
Out
Figure 2. Typical Connection Diagram
1. Grounding and power supply decoupling
The AK4532 requires careful attention to power supply and grounding arrangements. VD should be
supplied from analog power supply. Analog ground and digital ground should be connected
together near to where the supplies are brought onto the printed circuit board. Decoupling
capacitors should be as near to the AK4532 as possible, with the small value ceramic capacitor
being the nearest.
2. On-chip voltage reference
The on-chip voltage references are output on the VRAD and VCOM pins for decouping .
The VRAD is used as the reference of A/D conversion. The VCOM is a signal ground of this chip. An
electrolytic capacitor less than 10uF in parallel with a 0.1uF ceramic capacitor attached to these
pins eliminates the effects of high frequency noise. Especially, the small value ceramic capacitors
should be as near to the AK4532 as possible. No load current may be drawn from the VRAD and
0178-E-02
14
2004/12