Silan
Semiconductors
ELECTRONIC VOLUME
DESCRIPTION
The SC9235 and SC9235S are an optimum CMOS IC which
has been designed for electronization of volume control of audio
equipment, etc.
SC9235
SOP-16
FEATURES
* Attenuation can be controlled from 0dB to -78dB by up, down
input.
* This IC have 20dB tap for loudness circuit.
* This IC features a built-in DC output circuit (7 level) for volume
level meter.
* Polysilicon resistors enables low-distortion, high-performance
volume systems.
* Volume level remains in backup mode with low current
consumption.
* Package is DIP16 and SOP16.
DIP-16
ORDERING INFORMATION
SC9235
SC9235S
DIP-16 Package
SOP-16 Package
PIN CONFIGURATION
BLOCK DIAGRAM
V
SS
OUT-1
IN-1
1
2
3
4
5
DECODER
D-A
CONVERTER
16
15
14
13
12
V
DD
OUT-2
IN-2
TP-2
GND-2
V
SS
OUT-1
IN-1
TP-1
GND-1
UP
DN
OSC
1
2
3
4
SC9235
5
6
7
8
16
15
14
13
12
11
10
9
V
DD
OUT-2
IN-2
TP-2
GND-2
DC-OUT
INH
INT
TP-1
GND-1
UP
DN
6
7
11
UP/DOWN
COUNTER
DC-OUT
10
CONTROL
INH
OSC
8
9
INT
HANGZHOU SILAN MICROELECTRONICS JOINT-STOCK CO.,LTD
Rev: 1.0
2000.12.31
1
Silan
Semiconductors
ABSOLUTE MAXIMUM RATINGS
(Ta=25°C)
Characteristic
Supply Voltage
Input Voltage
Power Dissipation
Operating Temperature
Storage Temperature
SC9235
Symbol
V
DD
V
IN
P
D
Topr
Tstg
Value
-0.3 ~15
-0.3V ~ V
DD
+0.3V
300
-40 ~ +85
-55 ~ +150
Unit
V
V
mW
°C
°C
ELECTRICAL CHARACTERISTICS
(Unless otherwise specified, Ta = 25k,
Parameter
Operating Supply Voltage
Operating Supply Current
Backup Voltage
Backup Current
Input Voltage
"H" Level
"L" Level
Input Current
Pull Up Resistor
Volume Resistor
Analog Switch ON Resistor
Attenuation Error
Balance Between Left And Right
Total Harmonic Distortion
Maximum Attenuation
Cross Talk
Output Noise Voltage
OSC Frequency
"H" Level
"L" Level
V
DD
=
9V)
Symbol
V
DD
I
DD
V
QD
I
QD
V
IH
V
IL
I
IH
I
IL
R
UP
R
VR
R
ON
ΔATT
ΔR
VR
THD
ATT
MAX
C.T
V
N
f
OSC
Test Conditions
Ta=-40 ~ 85°C
No load,fosc=20Hz
INH
="L"
Min
4.5
--
2.0
--
Typ
9.0
0.3
--
0.01
--
--
--
--
47
44
500
0
0
0.01
100
100
2.0
20
Max
12
1.0
12
1.0
V
DD
0.3V
DD
1
1
71
58
800
±2.0
±3.0
--
--
--
--
--
Unit
V
μA
V
μA
V
μA
kΩ
kΩ
Ω
dB
%
%
dB
dB
μVrms
Hz
All input pin
V
IH
=V
DD
V
IL
=0V
UP
,
DN
,
INT
Input pin
0.7V
DD
0
INH
input pin
-1
-1
23
31
--
--
--
--
--
--
--
--
Between IN GND resistor
Analog switch ON resistor
--
Volume resistor error between
left and right
F
IN=
1kHz
V
IN
=1Vrms
R
L
=100kΩ
Rg=600Ω
Cx=2.2μF, Rx=33kΩ
0dB
0dB
∞dB
HANGZHOU SILAN MICROELECTRONICS JOINT-STOCK CO.,LTD
Rev: 1.0
2000.12.31
2
Silan
Semiconductors
PIN DESCRIPTION
Pin No.
1
16
2
15
3
14
4
13
5
12
6
SC9235
Description
Power Supply terminal
Symbol
Vss
V
DD
OUT-1
OUT-2
IN-1
IN-2
TP-1
TP-2
GND-1
GND-2
UP
Pin Name
Negative power supply pin
Positive power supply pin
Volume output pins
Volume circuit
OUT
IN
Volume input pins
Tap output pins for loudness
TP
GND
Analog ground pins
Volume up, down control input pin.
Volume up input pin
The 1 step / 1 push volume is controlled by pushing
the Up or Down key . If the key has been pushed
7
DN
Volume down input pin
continuously, the continuous volume control.
These two input pins have built-in pull-up resistor.
Oscillation pin.
8
OSC
Oscillation pin
Oscillator circuit consist of C.R connection.
Oscillation is executed while key is pushed.
Input pin for setting initial volume level volume level
9
INT
Initializing pin
set to 46dB by "L" input.
This input pin has built-in pull-up resistor.
Back up mode input pin.
10
INH
Inhibit terminal
Internal all operation is stopped by "L" input, and
volume level remains with low current consumption.
DC output pin for volume level meter.
11
DC-OUT
DC output pin for level meter
DC voltage which is corresponded to volume step is
generated.
HANGZHOU SILAN MICROELECTRONICS JOINT-STOCK CO.,LTD
Rev: 1.0
2000.12.31
3
Silan
Semiconductors
FUNCTION DESCRIPTION
1. VOLUME CIRCUIT
Volume circuit consist of ladder resistor and analog switch.
Tap for loudness is connected to step 10 (20dB).
Attenuation is as follows when resistor (3.9kΩ) is connected between TP pin and pin.
SC9235
*
Equivalence circuit
*
Volume step and attenuation
(Attenuation is as follows when resistor (3.9kΩ) is
OUT
IN
S
0
S
1
S
2
28.5kΩ
connected between TP pin and GND pin.)
Step
0
1
2
3
4
5
Attenuation
0(dB)
2
4
6
8
10
12
14
16
18
20
22
24
26
28
30
Step
16
17
18
19
20
21
*22
23
24
25
26
27
28
29
30
31
Attenuation
32(dB)
34
36
38
40
42
46
50
54
58
62
66
70
74
78
∞
S
9
6
TP
S
10
S
11
7
8
9
20.25kΩ
10
11
S
30
12
13
14
15
GND
S
31
* Step 22 (46dB) initial value.
HANGZHOU SILAN MICROELECTRONICS JOINT-STOCK CO.,LTD
Rev: 1.0
2000.12.31
4
Silan
Semiconductors
2. VOLUME UP, DOWN CONTROL CIRCUIT
Volume up, down control is executed by
UP
,
DN
key input.
* The 1 step / 1 push volume is controlled by "L" level of
UP
,
DN
key.
* If
UP
,
DN
key is input "L" continuously, volume level is changed continuously.
* Timing of key input
SC9235
UP / DN INPUT
VOLUME LEVEL
t
T
(f
OSC
=20Hz)
a
Note: t : Prevent time for chattering
T: Switching time to automatic mode
a : Up,Down speed
fosc
Cx•Rx(Hz) : Rx=12~220k¡
3. DC OUTPUT CIRCUIT FOR VOLUME LEVEL
DC output for volume level meter is internally connected to D−A converter (R/2R type).
8 stage output voltage which is corresponded to volume level is generated.
Because output impedance
≈
22kΩ (typ.) is high, If input impedance of next setting level meter IC is low,
set to Buffer.
Equivalence circuit
* Volume step and Output voltage
Step
2R
DC-OUT
2R
2R
R
R
Attenuation(dB)
0~6
8 ~ 14
16 ~ 22
24 ~ 30
32 ~ 38
40 ~ 50
54 ~ 66
70 ~
∞
Output Voltage(V)
7/ 8 V
DD
6/ 8 V
DD
5/ 8 V
DD
4/ 8 V
DD
3/ 8 V
DD
2/ 8 V
DD
1/ 8 V
DD
0
0~3
4~7
8 ~ 11
12 ~ 15
R
R≈22kΩ
16 ~ 19
20 ~ 23
24 ~ 27
28 ~ 31
HANGZHOU SILAN MICROELECTRONICS JOINT-STOCK CO.,LTD
Rev: 1.0
2000.12.31
5
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