Datasheet SC9235, SC9235S Datasheet (SILAN)

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ELECTRONIC VOLUME

DESCRIPTION

The SC9235 and SC9235S are an optimum CMOS ICwhich
has been designedfor electronization of volume control of audio
equipment, etc.

FEATURES

* Attenuation can be controlled from 0dB to -78dB by up, down

input.

* This IChave 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.

PIN CONFIGURATION BLOCK DIAGRAM

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SC9235

SOP-16

DIP-16

ORDERING INFORMATION

SC9235 DIP-16 Package
SC9235S SOP-16 Package

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V

16
15
14
13
12

11

10

9

DD

OUT-2

IN-2

TP-2

GND-2

DC-OUT

INH

INT

V

OUT-1

IN-1

TP-1

GND-1

OSC

V

SS

1

OUT-1

IN-1

TP-1

GND-1

OSC

UP

DN

2
3
4
5

DECODER

6

UP/DOWN
COUNTER

D-A

CONVERTER

7

CONTROL

8

SS

1
2
3
4

SC9235

5

UP

6

DN

7
8

16
15
14
13
12
11
10

9

DD

V

OUT-2

IN-2

TP-2

GND-2

DC-OUT

INH

INT

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Rev: 1.0 2000.12.31

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ABSOLUTE MAXIMUM RATINGS

Characteristic Symbol Value Unit

Supply Voltage V
Input Voltage V
PowerDissipation P
Operating Temperature Topr -40 ~ +85
Storage Temperature Tstg -55 ~ +150

ELECTRICAL CHARACTERISTICS

Parameter Symbol Test Conditions Min Typ Max Unit

Operating Supply Voltage V
Operating Supply Current I
Backup Voltage V
Backup Current I

Input Voltage

Input Current

Pull Up Resistor R
Volume Resistor R
Analog Switch ON Resistor R
Attenuation Error

Balance Between Left And Right

Total Harmonic Distortion THD 0dB -- 0.01 -- %
Maximum Attenuation ATT
Cross Talk
Output Noise Voltage V
OSC Frequency f

"H" Level V
"L" Level V
"H" Level I
"L" Level I

DD

DD

QD

QD

IH

IL

IH

IL

UP

VR

ON

∆ATT

∆R

VR

MAX

C.T

N

OSC

(Ta=25°C)

DD

IN

D

-0.3 ~15 V

-0.3V ~ VDD+0.3V V
300 mW

(Unless otherwise specified, Ta = 25k,V

Ta=-40 ~ 85°C

No load,fosc=20Hz -- 0.3 1.0

="L"

INH

All input pin

input pin

INH

UP,DN,INT

VIH=V

Input pin

V

=0V -1 -- 1

IL

0.7V

DD

BetweenINGND resistor 31 44 58
Analog switch ON resistor -- 500 800

-- -- 0
Volume resistor error between
left and right

F

1kHz

IN=

V

=1Vrms

IN

R

=100kΩ

L

Rg=600Ω

∞dB

0dB

Cx=2.2µF, Rx=33kΩ

HANGZHOU SILAN MICROELECTRONICS JOINT-STOCK CO.,LTD

2

SC9235

°C
°C

9V)

=

DD

4.5 9.0 12 V

2.0 -- 12 V

-- 0.01 1.0

-- V

DD

0--0.3V

-1 -- 1

23 47 71

-- 0

-- 100 -- dB

-- 100 -- dB

-- 2.0 --

-- 20 -- Hz

DD

DD

±2.0

±3.0

µVrms

Rev: 1.0 2000.12.31

µA

µA

µA

kΩ
kΩ

dB

V

Ω

%

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PIN DESCRIPTION

Pin No. Symbol Pin Name Description

1 Vss Negative power supply pin

16 V

2OUT-1

15 OUT-2

3IN-1

14 IN-2

4TP-1

13 TP-2

5 GND-1

12 GND-2

6

7

8 OSC Oscillation pin

9

10

11 DC-OUT DCoutput pin for level meter

UP

DN

INT

INH

Positive power supply pin

DD

Volume output pins

Volume input pins

Tap output pins for loudness

Analog ground pins

Volume up input pin

Volume down input pin

Initializing pin

Inhibit terminal

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Power Supply terminal

Volume circuit

OUT

IN

TP

GND

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.
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
set to 46dB by "L" input.
This input pin has built-in pull-up resistor.
Back up mode input pin.
Internal all operation is stopped by "L" input, and
volume level remains with low current consumption.
DC output pin for volume level meter.
DC voltage which is corresponded to volume step is
generated.

SC9235

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Rev: 1.0 2000.12.31

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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.

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SC9235

* Equivalence circuit

OUT

IN

28.5kΩ

TP

20.25kΩ

GND

* Volume step and attenuation

(Attenuation is as follows when resistor (3.9kΩ)is
connected between TP pin and GND pin.)

S

0

S

1

S

2

S

9

S

10

S

11

S

30

31

S

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
5102142
6 12 *22 46
7142350
8162454

9182558
10 20 26 62
11 22 27 66
12 24 28 70
13 26 29 74
14 28 30 78
15 30 31

∞

* Step 22 (46dB) initial value.

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Rev: 1.0 2000.12.31

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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
*If

UP , DN key is input "L" continuously, volume level is changed continuously.

* Timing of key input

UP / DN INPUT

VOLUME LEVEL

tT a

(f

OSC

=20Hz)

Note: t : Prevent time for chattering  2.21/fosc(110ms)

T: Switching time to automatic mode  101/fosc(500ms)
a : Up,Down speed  21/fosc(100ms)
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.

UP , DN key.

SC9235

 Equivalence circuit

R≈22kΩ

HANGZHOU SILAN MICROELECTRONICS JOINT-STOCK CO.,LTD

2R

2R

2R

R

R

R

DC-OUT

* Volume step and Output voltage

Step Attenuation(dB) Output Voltage(V)

0~3 0~6 7/8VDD
4~7 8~14 6/8VDD

8 ~ 11 16 ~ 22 5/ 8 VDD
12 ~ 15 24 ~ 30 4/ 8 VDD
16 ~ 19 32 ~ 38 3/ 8 VDD
20 ~ 23 40 ~ 50 2/ 8 VDD
24 ~ 27 54 ~ 66 1/ 8 VDD
28 ~ 31

70 ~ ∞

Rev: 1.0 2000.12.31

5

0

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4. INITIALIZATION AND BACKUP OPERATION

1) Initialization operation
When power on, volume level is set to initial value (46dB) by setting

DD

V

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DD

V

SC9235

INT pin to "L" level for a while.

V

IL

0V

Adjust condenser value which is set INT pin to the period while INT pin is "L" level is longer than 1ms when

Power on.

2) Backup operation
Internal operation is all stopped when
Volume data is remains while Backup mode with low current consumption.

DD

V

0V

NORMAL MODE BACKUP MODE NORMAL MODE

tt≥1ms

INH pin is "L" level, and prohibit input and output.

V

DD

INH

INT

Back up

V

DD

2V

MIN≥2.0V

Minimum Voltagefor Back up is 2.0V.

Back up data is lost

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TEST CIRCUITS

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V

DD

AVIDD/I

QD

SC9235

V

V-M

L

R

1/2 VDD

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THD —Vout

1

fin=1kHz,Rg=600Ω

RL=100kΩ,HPF=20Hz

LPF=80kHz

0.1

THD (%)

0.01

0.001

0.01 0.1 1 10

Vout (Vrms)

SG

R

X

VDD=6.0V

VDD=12.0V

600Ω

VDD=9.0V

SG

INH

47µF

V-M

R

L

1/2 VDD

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V

DD

1
2
3
4

16
15
14
13

600Ω

SC9235

5
6
7
8

C

X

12
11
10

9

C

INT

LD CHARACTERISTIC

10

0

-10

-20

-30

-40

-50

-60
10 100 1000 10000 100000

fin (Hz)

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Rev: 1.0 2000.12.31

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TYPICAL APPLICATION CIRCUIT

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SC9235

Condenser for Backup

V

SS

1

OUT

L-

ch

IN

1/2 V

DOWN Key

LEFT SIDE RIGHT SIDE

(Note) Loudness circuit is left side, only volume (without loudness) circuit is right side.

C1=1500pF C1=0.1µFR=8.2kΩ

DD

UP Key

C1

R

3.9kΩ

C2

2
3
4
5
6

UP

DN

7

Rx

Cx

OSC

8

LEVEL METER

V

DC-OUT

INH

INT

DRIVER IC

1/2 V

DD

DD

16
15
14

3.9kΩ

13
12
11
10

4.7kΩ

9

1/2 V

OUT

IN

+B

R-

ch

DD

HANGZHOU SILAN MICROELECTRONICS JOINT-STOCK CO.,LTD

Rev: 1.0 2000.12.31

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PACKAGE OUTLINE

16-DIP-P-300 UNIT:mm

2.54

SC9235

0.25

6.40

3.51

19.4

1.50

0.46

7.62

15 degree

5.083.30

16-SOP-P-225 UNIT:mm

0.41

3.95

6.00

5.72

1.27

10.20

9.80

1.95

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HANGZHOU SILAN MICROELECTRONICS JOINT-STOCK CO.,LTD

Rev: 1.0 2000.12.31

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