KA9270
AUDIO FILTER
INTRODUCTION
The KA9270 is a monolithic integrated circuit designed for audio
filter. It is used in compact disc player, digital audio tape recorder,
etc.
FEATURES
Functions:
Gain adjustable of audio output
Minimum number of external parts required
Recommand operation supply voltage range : 5.0 ~ 12.0V
BLOCK DIAGRAM
Device
Package
Operating Temperature
KA9270
20-DlP-300A
KA9270D
20-SOP- 375
20
19
18
17
16
15
14
1
3
12
11
1
2
3
4
5
6
7
8
9
10
-
+
-
+
-
+
-
+
-
+
MUTE
SW
DE-EM
SW
-
+
-
+
BUFFER2
BUFFER1
DE-AMP2
DE-AMP1
Vcc
LPF1
LPF2
LPF
OUTPUT2
LPF2B
V
REF
RIPPLE
DE-EMPHA
CTL
DE-EMPHA
OUT2
DE-EMPHA
IN3
BUFFER
OUT2
INPUT2
1/2Vcc-AMP
GND
LPF
OUTPUT1
LPF1B
MUTE
CONTROL
INPUT
DE-EMPHA
CONTROL
INPUT
DE-EMPHA
CTL
DE-EMPHA
OUT1
DE-EMPHA
IN1
BUFFER
OUT1
INPUT1
20
C ~ +75
C
20-DIP-300A
20-SOP-375
Fig. 1
* Buffer for impedence matching
* Low pass filter
* De - emphasis control
* Mute control
* Reference voltage circuit ( 1/2 V
CC
AMP )
KA9270
AUDIO FILTER
ABSOLUTE MAXIMUM RATINGS
(Ta = 25
C)
ELECTRICAL CHARACTERISTICS
(Ta = 25
C, V
CC
= 8V, f = 1KHz, R
L
= 10K
, De-emphasis; off, Mute; off, S1 & S2; off, unless otherwise specified)
Note: De-emphasis input conditions: V
O
= 0dBm
De-emphasis off position
Characteristic
Symbol
Value
Unit
Supply Voltage
Power Dissipation
Operating Temperature
Storage Temperature
V
CC
P
D
T
OPR
T
STG
16
550
-20 ~ + 75
-45 ~ + 150
V
W
C
C
Characteristic
Symbol
Test Conditions
Min
Typ
Max
Unit
Quiescent Circuit Current
I
CC
V
I
= 0
1
4
6
mA
Maximum Output Voltage
V
OM
THD = 1%
1.8
2.1
Vrms
f = 100Hz
0.01
0.05
f = 1KHz
0.01
0.05
Total Harmonic Distortion
THD
V
O
= 0dBm
f = 10KHz
0.05
0.1
%
f = 16KHz
0.1
0.2
f = 20KHz
0.1
0.2
f = 100Hz
-0.1
0
0.1
f = 1KHz
0
0
0
Frequency Characteristics
fv
V
O
= 6dBm
f = 10KHz
-0.5
0
0.5
dB
f = 16KHz
-1.0
0
1.0
f = 20KHz
-1.5
0
1.5
f = 100Hz
70
80
Cross Talk
CT
V
O
= 0dBm
f = 1KHz
65
75
dB
f = 10KHz
60
65
Signal to Noise Ratio
S/N
V
O
= 0dBm, R
G
= 600
20KHz LPF
73
80
dB
Channel Balance
CB
V
O
= 0dBm
-1.0
0
1.0
dB
Open Loop Gain
G
VO
V
I
= 900mVrms
-2.6
-0.6
1.0
dB
Gain Adjusting Range
G
VR
V
I
= 900mV, S1, S2; ON
4.5
6
dB
Mute Attenuation Ratio
ATT
MUTE
V
I
= 900mV, Mute SW; ON
40
50
dB
f = 1KHz
-0.87
-0.37
0.13
De-emphasis
DE
EMPH
De-emphasis: ON
f = 5KHz
-6.03
-4.53
-3.03
dB
f = 16KHz
-10.53
-9.03
-7.53
KA9270
AUDIO FILTER
TEST CIRCUIT
Fig. 2
+
20
19
18
17
16
15
14
1
3
12
11
1
2
3
4
5
6
7
8
9
10
+
+
+
-
+
-
+
-
+
-
+
MUTE
SW
DE-EM
SW
-
+
-
+
+
+
CH2
OUTPUT
(Vo)
3.3
Vcc
47
0.01
10K
330pF
5.6K
0.0015
1/2 Vcc
5.6K 5.6K
4.7
1M
0.0012
12K
27K
27K
4.7
5K
CH2-INPUT
(from SIGNAL
GENERATOR
OUTPUT)
+
-
VI
1/2 Vcc
BUFFER2
BUFFER1
CH1-INPUT
(from SIGNAL
GENERATOR
OUTPUT)
DE-AMP2
DE-AMP1
Vcc
LPF1
LPF2
CH1
OUTPUT
(Vo)
10K
3.3
330pF
5.6K
5.6K
0.0015
MUTE
CONTROL
SIGNAL
(MUTE)
DE-EMPHASIS
CONTROL
SIGNAL
(DE-EM)
5.6K
27K
27K
12K
1M
0.0012
4.7
5K
VI
+
-
-
+
KA9270
AUDIO FILTER
APPLICATION INFORMATION
1. BUFFER
Fig. 3
It is used for impedance matching, between D/A converter output and de-emphasis input.
2. DE-EMPHASIS
a) De-emphasis operation condition
b) De-emphasis characteristic at the de-emphasis ON
Fig. 4 Equevalent Circuit of De-emphasis ON Mode
The de-emphasis charcteristics is dependent on the external parts value.
+
-
INPUT
(from D/A Converter
Output)
to De-emphasis input
Control Input
De-emphasis Operation
High
ON
Low
OFF
+
-
Vi
R6
R5
R4
Vo
C1
Av R
4
/ R
6
T1 = C1 (R
4
+ R
5
)
T2 = C
1
X R
5
KA9270
AUDIO FILTER
3. MUTE
Fig. 5 Equivalent Circuit of Mute Switch ON Mode
Mute attenuation [M (att)] ratio is as follow;
M (att) = 20 log
= 20 log (dB)
4. LOW PASS FILTER
Fig. 6 Equivalent Circuit of LPF
Cut off frequency (F
C
) is as follow:
f
C
= (Hz)
+
-
Vi
R6
Vo
R
QON
+
-
Vi
R3
R2
R1
C4
C3
Where:
R
QON
= internal TR
ON resistance
V
O
V
I
R
QON
R
6
1
2
R
2
R
1
C
3
C
4
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