ASAHI KASEI
[AKD4385-B]
<KM075400>
- 1 -
2004/07
General Description
The AKD4385 -B is an evaluation board for AK4385, which is 192kHz sampling 24Bit
DAC. The AKD4385
-B includes a LPF which can add differential analog outputs from the AK4385 and also has a digital interface.
Therefore, it is easy to evaluate the AK4385.
<
Ordering Guide
AKD4385-B
--- Evaluation board for AK4385
Function
<
On-board Analog output buffer circuit
<
On board digital audio interface (AK4113)
OPT in
COAX in
AK4113
AK4385
Output LPF
Rch
Lch
DIR
Figure 1. Block diagram
Circuit diagram and PCB layout are attached at the end of this manual.
COAX is recommended for an evaluation of the sound quality.
Evaluation board for AK4385
AKD4385-B
ASAHI KASEI
[AKD4385-B]
<KM075400>
- 2 -
2004/07
n
Operation sequence
1) Set up the power supply lines. (See "Other jumpers set-up".)
Name
Color
Voltage
Comments
Attention
+12V
Red
+12
+15V
Regulator,
Power supply for Op-amp.
This jack is always needed. Power line
-12V
Blue
-12
-15V
Regulator,
Power supply for Op-amp.
This jack is always needed. Power line
AGND
Black
0V
GND
This jack is always needed.
Table 1. Set up of power supply lines
Each supply line should be distributed from the power supply unit.
2) Set-up the jumper for power supply
[JP2 (AVDD)] selects power supply for DVDD pin of AK4385.
short:
5V is supplied from T3.
In the case, JP1 should be open.
open:
5V is supplied from T2. (default)
[JP1(DVDD)] selects power supply for DVDD pin of AK4385.
open:
5V is supplied from T2.
In the case, JP1 should be short.
short:
5V is supplied from T2. (default)
3) Set-up the jumper pins
4) Set-up the DIP switches. (See the followings.)
5) Power on
The AK4385 should be reset once bringing SW1 (PDN) "L" upon power-up.
ASAHI KASEI
[AKD4385-B]
<KM075400>
- 3 -
2004/07
n
Evaluation mode
1.
DIR(COAX Link) (default)
J1 is used for the evaluation using such as CD test disk. The DIR generates MCLK, BICK and LRCK SDATA from the
received data through BNC connector (J1). Setting of jumper is shown below.
COAX is recommended for an evaluation of the sound quality.
JP3
OPT
COAX
BNC
(Default)
JP1
DVDD
JP2
AVDD
Figure 2. Jumper setting, when using DIR
2.
DIR(Optical Link)
J1 is used for the evaluation using such as CD test disk. The DIR generates MCLK, BICK and LRCK SDATA from the
received data through
optical connector (PORT2: TORX176).
Setting of jumper is shown below.
JP3
OPT
COAX
PORT1
JP1
DVDD
JP2
AVDD
Figure 3.
Jumper setting, when using DIR
n
DIP Switch setting
[SW2]: AK4113 setting
No.
Pin
OFF
ON
Default
1
OCKS1
ON
2
OCKS0
AK4113 Master Clock setting
Refer to Table3
OFF
Table 2. SW2 setting
The frequencies of the master clock output is set by OCKS0 and OCKS1 as shown in Table 3.
OCKS1
OCKS0
MCLK Frequency
0
0
256fs @fs=88.2/96kHz
1
0
512fs @32/44.1/48kHz
1
1
128fs @176.4/192kHz
Default
Table 3. MCLK Clock
n
SW1 setting
[SW1](PDN): Reset of AK4385. Select "H" during operation
.
ASAHI KASEI
[AKD4385-B]
<KM075400>
- 4 -
2004/07
<
External Analog Circuit
The 2nd order LPF (fc=93.2kHz, Q=0.712) which adds differential outputs of the AK4385 is implemented on the board. When
the further attenuation of the out-band noise is needed, some additional LPF is required. Analog signal is output through BNC
connectors on the board. And the output level of the AK4385 is 5.5Vpp@5V.
LOUT-
(ROUT-)
-
LOUT+
(ROUT+)
+15V
-15V
NJM4580D
R
1
C
1
R
3
R
2
C
2
R
1
R
3
R
2
C
2
22u
10k
+
100
Figure 4. On-board analog filter
R
1
R
2
R
3
C
1
C
2
4.7k
4.7k
200
3300p
470p
Table 4. The value of R, C on this board
fin
20kHz
40kHz
80kHz
Frequency Response
-0.003dB
-0.122dB
-1.821dB
Table 5. Frequency Response of LPF
<Calculation>
fc=
0
2
,
0
=
1
2C
1
C
2
R
2
R
3
,
Q=
2C
1
0
.
+
1
R
1
+
1
R
2
1
R
3
Amplitude = 20 log
[1-(f/fc)
2
]
2
+[(1/Q)(f/fc)]
2
K
[dB],
K=
R
2
R
1
,
ASAHI KASEI
[AKD4385-B]
<KM075400>
- 5 -
2004/07
Measurement Results
[Measurement condition]
Measurement unit
: Audio Precision System two Cascade (AP2)
MCLK
: 512fs (44.1kHz),256fs (96kHz), 128fs (192kHz)
BICK
: 64fs
fs
: 44.1kHz, 96kHz, 192kHz
Bit
: 24bit
Power Supply
: VDD=5V
Interface
: Internal DIR (48kHz, 96kHz, 192kHz)
Temperature
: Room
fs=44.1kHz
Parameter
Input signal
Measurement filter
Results
S/(N+D)
1kHz, 0dB
20kLPF
95.2 dB
DR
1kHz, -60dB
22kLPF, A-weighted
107.9 dB
S/N
"0" data
22kLPF, A-weighted
109.0 dB
fs=96kHz
Parameter
Input signal
Measurement filter
Results
S/(N+D)
1kHz, 0dB
40kLPF
92.2 dB
DR
1kHz, -60dB
40kLPF
102.7 dB
DR
1kHz, -60dB
22kLPF, A-weighted
107.6 dB
S/N
"0" data
40kLPF
103.1 dB
S/N
"0" data
22kLPF, A-weighted
108.5 dB
fs=192kHz
Parameter
Input signal
Measurement filter
Results
S/(N+D)
1kHz, 0dB
40kLPF
91.7 dB
DR
1kHz, -60dB
40kLPF
101.2 dB
DR
1kHz, -60dB
22kLPF, A-weighted
106.1 dB
S/N
"0" data
40kLPF
102.4 dB
S/N
"0" data
22kLPF, A-weighted
107.6 dB
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