Silan
Semiconductors
SC9235
HANGZHOU SILAN MICROELECTRONICS JOINT-STOCK CO.,LTD
Rev: 1.0
2000.12.31
1
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.
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
SOP-16
ORDERING INFORMATION
SC9235
DIP-16 Package
SC9235S
SOP-16 Package
PIN CONFIGURATION BLOCK DIAGRAM
SC9235
16
15
14
13
12
11
10
9
1
2
3
4
5
6
7
8
V
SS
OUT-1
IN-1
TP-1
GND-1
OSC
DC-OUT
GND-2
TP-2
IN-2
OUT-2
V
DD
INH
INT
DN
UP
DECODER
UP/DOWN
COUNTER
CONTROL
6
7
8
D-A
CONVERTER
11
10
9
5
4
12
13
14
15
16
3
2
1
V
SS
OUT-1
IN-1
TP-1
GND-1
OSC
DC-OUT
GND-2
TP-2
IN-2
OUT-2
V
DD
INH
INT
DN
UP
Silan
Semiconductors
SC9235
HANGZHOU SILAN MICROELECTRONICS JOINT-STOCK CO.,LTD
Rev: 1.0
2000.12.31
2
ABSOLUTE MAXIMUM RATINGS
(Ta=25
C)
Characteristic Symbol Value Unit
Supply Voltage
V
DD
-0.3 ~15
V
Input Voltage
V
IN
-0.3V ~ V
DD
+0.3V
V
Power Dissipation
P
D
300
mW
Operating Temperature
Topr
-40 ~ +85
C
Storage Temperature
Tstg
-55 ~ +150
C
ELECTRICAL CHARACTERISTICS
(Unless otherwise specified, Ta = 25
k
, V
DD
=
9V)
Parameter Symbol
Test
Conditions
Min
Typ
Max
Unit
Operating Supply Voltage
V
DD
Ta=-40 ~ 85
C
4.5
9.0
12
V
Operating Supply Current
I
DD
No load,fosc=20Hz
--
0.3
1.0
A
Backup Voltage
V
QD
2.0
--
12
V
Backup Current
I
QD
INH ="L"
--
0.01
1.0
A
"H" Level
V
IH
0.7V
DD
--
V
DD
Input Voltage
"L" Level
V
IL
All input pin
0
--
0.3V
DD
V
"H" Level
I
IH
V
IH
=V
DD
-1
--
1
Input Current
"L" Level
I
IL
INH input pin
V
IL
=0V
-1
--
1
A
Pull Up Resistor
R
UP
UP
,
DN
,
INT
Input pin
23
47
71
k
Volume Resistor
R
VR
Between IN
GND resistor
31
44
58
k
Analog Switch ON Resistor
R
ON
Analog switch ON resistor
--
500
800
Attenuation Error
ATT
--
--
0
2.0
dB
Balance Between Left And Right
R
VR
Volume resistor error between
left and right
--
0
3.0
%
Total Harmonic Distortion
THD
0dB
--
0.01
--
%
Maximum Attenuation
ATT
MAX
dB
--
100
--
dB
Cross Talk
C
.
T
--
100
--
dB
Output Noise Voltage
V
N
F
IN=
1kHz
V
IN
=1Vrms
R
L
=100k
Rg=600
0dB
--
2.0
--
Vrms
OSC Frequency
f
OSC
Cx=2.2
F, Rx=33k
--
20
--
Hz
Silan
Semiconductors
SC9235
HANGZHOU SILAN MICROELECTRONICS JOINT-STOCK CO.,LTD
Rev: 1.0
2000.12.31
3
PIN DESCRIPTION
Pin No.
Symbol
Pin Name
Description
1
Vss
Negative power supply pin
16
V
DD
Positive power supply pin
Power Supply terminal
2
OUT-1
15
OUT-2
Volume output pins
3
IN-1
14
IN-2
Volume input pins
4
TP-1
13
TP-2
Tap output pins for loudness
5
GND-1
12
GND-2
Analog ground pins
Volume circuit
OUT
IN
TP
GND
6
UP
Volume up input pin
7
DN
Volume down input pin
Volume up, down control input pin.
The 1 step / 1 push volume is controlled by pushing
the Up or Down key . If the key has been pushed
continuously, the continuous volume control.
These two input pins have built-in pull-up resistor.
8
OSC
Oscillation pin
Oscillation pin.
Oscillator circuit consist of C.R connection.
Oscillation is executed while key is pushed.
9
INT
Initializing pin
Input pin for setting initial volume level volume level
set to 46dB by "L" input.
This input pin has built-in pull-up resistor.
10
INH
Inhibit terminal
Back up mode input pin.
Internal all operation is stopped by "L" input, and
volume level remains with low current consumption.
11
DC-OUT
DC output pin for level meter
DC output pin for volume level meter.
DC voltage which is corresponded to volume step is
generated.
Silan
Semiconductors
SC9235
HANGZHOU SILAN MICROELECTRONICS JOINT-STOCK CO.,LTD
Rev: 1.0
2000.12.31
4
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 (3.9k
) is connected between TP pin and pin.
*
Volume step and attenuation
(Attenuation is as follows when resistor (3.9k
) is
connected between TP pin and GND pin.)
Step Attenuation Step Attenuation
0
0(dB)
16
32(dB)
1
2
17
34
2
4
18
36
3
6
19
38
4
8
20
40
5
10
21
42
6
12
*22
46
7
14
23
50
8
16
24
54
9
18
25
58
10
20
26
62
11
22
27
66
12
24
28
70
13
26
29
74
14
28
30
78
15
30
31
*
Equivalence circuit
OUT
IN
TP
GND
S
31
S
30
S
11
S
10
S
9
S
2
S
1
S
0
28.5k
20.25k
* Step 22 (46dB) initial value.
Silan
Semiconductors
SC9235
HANGZHOU SILAN MICROELECTRONICS JOINT-STOCK CO.,LTD
Rev: 1.0
2000.12.31
5
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
t
T
a
UP / DN INPUT
VOLUME LEVEL
(f
OSC
=20Hz)
Note: t : Prevent time for chattering
2.2
h
1/fosc(
110ms)
T: Switching time to automatic mode
10
h
1/fosc(
500ms)
a : Up,Down speed
2
h
1/fosc(
100ms)
fosc
CxRx(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
22k
(typ.) is high, If input impedance of next setting level meter IC is low,
set to Buffer.
* Volume step and Output voltage
Step Attenuation(dB)
Output
Voltage(V)
0 ~ 3
0 ~ 6
7/ 8 V
DD
4 ~ 7
8 ~ 14
6/ 8 V
DD
8 ~ 11
16 ~ 22
5/ 8 V
DD
12 ~ 15
24 ~ 30
4/ 8 V
DD
16 ~ 19
32 ~ 38
3/ 8 V
DD
20 ~ 23
40 ~ 50
2/ 8 V
DD
24 ~ 27
54 ~ 66
1/ 8 V
DD
Equivalence circuit
DC-OUT
R
R
R
2R
2R
2R
R
22k
28 ~ 31
70 ~
0
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