ANGUS ELECTRONIC COMPANY LIMITED Princeton Technology Corp.
Tel: (852) 2345 0540 Fax: (852) 2345 9948 Web Site: www.angus.com.hk
Electronic Volume Controller IC
PT2253A
DESCRIPTION PT2253A is an electronic volume controller IC utilizing CMOS Technology specially designed for use on audio equipments. It has two (2) built-in channels making it ideally suitable for mono and stereo sound applications. PT2253A provides a wide frequency response range and a very low harmonic distortion to mention a few; thereby guaranteeing a highly effective and reliable performance.
FEATURES ❒ ❒ ❒ ❒ ❒ ❒ ❒ ❒ ❒ ❒
CMOS Technology Low Power Consumption Operating Voltage Range : Vcc = 6 ~ 12 V (Backup Voltage is up to 4 V) 0dB to -68dB attenuation controlled by 2dB/step 2 Channels in each chip Capable to control attenuation by a built-in oscillator and Up/Down Pin Single Power Supply or Dual Power Supplies of (+) and (-) can be used Wide Frequency Response Range Very Low Harmonic Distortion Available in 16 pin, DIP Package
APPLICATIONS ❒ ❒
Audio Equipment Volume Control Traditional VR Replacement
PT2253A v 2.6
Page 1
Revised October 1999
ANGUS ELECTRONICS COMPANY LIMITED Princeton Technology Corp.Tel: (852) 2345 0540 Fax: (852) 2345 9948 Web Site: www.angus.com.hk
Electronic Volume Controller IC
PT2253A
BLOCK DIAGRAM Vcc
U/D
U/D CK
OSC
INH
Vss
7 BITS BIDIRECTIONAL SHIFT REGISTER
U/D
INT
CK
5 BITS BIDIRECTIONAL SHIFT REGISTER
AUTO INITIALIZE CIRCUIT INT
OSC
CONSTANT CURRENT CIRCUIT
DCO
Vcc L-OUT1 R-OUT1
A-SW A-SW A-SW A-SW A-SW A-SW
CK 7 BITS LATCH CIRCUIT
A-SW
7 BITS LATCH CIRCUIT
CK L-IN1
CK
CK
R-IN1
A-SW A-SW A-SW A-SW A-SW A-SW A-SW
A-GND
A-SW A-SW A-SW A-SW A-SW
CK
CK 6 BITS LATCH CIRCUIT
L-IN2
6 BITS LATCH CIRCUIT
A-GND
CK
CK
A-SW L-OUT2
R-IN2
A-SW A-SW A-SW A-SW A-SW A-SW
R-OUT2
PIN CONFIGURATION Vss
1
16
Vcc
L-OUT1
2
15
R-OUT1
L-IN1
3
14
R-IN1
A-GND
4
13
A-GND
L-IN2
5
12
R-IN2
L-OUT2
6
11
R-OUT2
INH
7
10
U/D
DCO
8
9
OSC
PT2253A PT2253A v 2.6
Page 2
Revised October 1999
ANGUS ELECTRONICS COMPANY LIMITED Princeton Technology Corp.Tel: (852) 2345 0540 Fax: (852) 2345 9948 Web Site: www.angus.com.hk
Electronic Volume Controller IC
PT2253A
PIN DESCRIPTION
Pin Name
Pin No.
I/O
Description
Vss L-OUT1
1 2
Power O
L-IN1 A-GND L-IN2
3 4 5 6
I GND I O
7
I
DCO OSC U/D R-OUT2 R-IN2 A-GND R-IN1 R-OUT1
8 9 10 11 12 13 14 15
O I/O I O I GND I O
Vcc
16
Power
Negative Power Supply 10dB/Step Attenuator Output A signal applied to ‘IN’ is attenuated into 7 steps from 0dB to -60dB. 10dB/Step Attenuator Input Analog Ground Pin 2dB/Step Attenuator Input 2dB/Step Attenuator Output A signal applied to ‘IN’ is attenuated into 5 steps from 0dB to -8dB. Inhibit Terminal. At “L” level, all inputs and outputs are disabled. At “H” level, operation is normal. DC Current Output Pin RC Connecting Pin for the Oscillator Attenuator Up/Down Control Pin 2dB/Step Attenuator Output, same as L-OUT2. 2dB/Step Attenuator Input, same as L-IN2. Analog Ground Pin 10dB/Step Attenuator Input, same as L-IN1. 10dB/Step Attenuator Output, same as LOUT1. Positive Power Supply
L-OUT2
INH
PT2253A v 2.6
Page 3
Revised October 1999
ANGUS ELECTRONICS COMPANY LIMITED Princeton Technology Corp.Tel: (852) 2345 0540 Fax: (852) 2345 9948 Web Site: www.angus.com.hk
Electronic Volume Controller IC
PT2253A
FUNCTIONAL DESCRIPTION Attenuation Setting The Attenuation can be increased or decreased depending on the state of the U/D Pin (either “H” or “L” Level) by actuating the built-in oscillator. When power is applied, the attenuation is automatically set at -40dB.
When the DOWN Key is pressed, the U/D Pin goes to the “L” Level and the oscillator is actuated in the down state. Thus, attenuation is increased. Conversely, when the UP Key is pressed, the U/D Pin goes to the “H” Level and the oscillator is actuated in the up state. Thus, attenuation is decreased. Oscillation frequency (fosc) is dependent on the Cx and the Rx and is determined by the following equation:
PT2253A v 2.6
Page 4
Revised October 1999
ANGUS ELECTRONICS COMPANY LIMITED Princeton Technology Corp.Tel: (852) 2345 0540 Fax: (852) 2345 9948 Web Site: www.angus.com.hk
Electronic Volume Controller IC
PT2253A
Vcc
16 Cx
Rs
OSC 9
OSC Vcc
Rx U/D 10 UP
DOWN 1µF
Rx = 33 K Cx = 4.7 uF Rs = 100 K
Vss
PT2253A has a DC Current Output Pin (DCO). The output level is divided into 13 steps. Please refer to the table below: STEP 0 1 2 3 4 5 6 7 8 9 10 11 12 13 PT2253A v 2.6
DCO 0 I 2I 3I 4I 5I 6I 7I 8I 9I 10I 11I 12I 13I
ATTENUATION -64dB ~ ∞ -60dB ~ -62dB -54dB ~ -58dB -50dB ~ -52dB -44dB ~ -48dB -40dB ~ -42dB -34dB ~ -38dB -30dB ~ -32dB -24dB ~ -28dB -20dB ~ -22dB -14dB ~ -18dB -10dB ~ -12dB -4dB ~ - 8dB 0dB ~ -2dB Page 5
Revised October 1999
ANGUS ELECTRONICS COMPANY LIMITED Princeton Technology Corp.Tel: (852) 2345 0540 Fax: (852) 2345 9948 Web Site: www.angus.com.hk
Electronic Volume Controller IC
PT2253A
Current value may fluctuate depending on the IC. When high precision is required, use a variable resistor as a load resistor.
Attenuator Attenuator 1 attenuates 0 ~ -60dB at 10dB/step. Attenuator 2 attenuates 0 ~ -8dB at 2 dB/step.
PT2253A v 2.6
Page 6
Revised October 1999
ANGUS ELECTRONICS COMPANY LIMITED Princeton Technology Corp.Tel: (852) 2345 0540 Fax: (852) 2345 9948 Web Site: www.angus.com.hk
Electronic Volume Controller IC
PT2253A
If there is the possibility of excessive voltage in the attenuator, it is recommended that a protective diode be inserted. Please refer to the diagram below. Vcc
Vcc IN
Vss Vss
Power Supply DUAL POWER SUPPLY
+Vcc Vcc
U/D
OSC
OSC
0V
A-GND Vss
INH
U/D
-Vss
DCO DC UP
Vcc
DOWN
SINGLE POWER SUPPLY +
Vcc
U/D
OSC
A-GND Vss
INH
DCO +Vcc
1/2 VDD
(A-GND)
DC
0V (Vss)
Vcc
PT2253A v 2.6
Page 7
Revised October 1999
ANGUS ELECTRONICS COMPANY LIMITED Princeton Technology Corp.Tel: (852) 2345 0540 Fax: (852) 2345 9948 Web Site: www.angus.com.hk
Electronic Volume Controller IC
PT2253A
Initialization When Power ON PT2253A has the built-in auto-initializing function for the during the Power ON period. It has the power supply on reset for the initialization of the chip. If the power supply rises too fast, the initialization may not be fully effected. For initialization to be fully effective, it is necessary to satisfy the following conditions: 1. The INH Terminal must be raised simultaneously with the Supply Voltage. 2. Initial attenuation level is -40dB Please refer to the following diagram.
Vcc-Vss = 4.0 V Vcc-Vss or INH TERMINAL VOLTAGE
T
1 msec
T
* If Vcc-Vss drops below 4.0 V, the auto-initializing function is actuated.
Back Up When Power OFF When INH Pin is set at “L” Level, all input and output pins are disabled and the current consumption is reduced to the minimum. Under this conditions, the backup by means of a capacitor becomes possible. An example of this application when a backup capacitor is used is shown below.
PT2253A v 2.6
Page 8
Revised October 1999
ANGUS ELECTRONICS COMPANY LIMITED Princeton Technology Corp.Tel: (852) 2345 0540 Fax: (852) 2345 9948 Web Site: www.angus.com.hk
Electronic Volume Controller IC
PT2253A
Vcc
VDD 10K
Vcc
PT2253A
10K 1000u 16V
Vss
INH
Vss 51K
• If Vcc-Vss drops below 4.0 V, the backup becomes impossible.
DC ELECTRICAL CHARACTERISTICS (Unless otherwise specified, Vcc = 12 V, Vss = 0 V and Ta = 25 oC) PARAMETER
SYMBOL
Operating Supply Voltage Operating Supply Current Stand-by-Current
Vcc Icc ISB
Input Voltage “H” Level (INH,U/D) “L” Level Attenuator 1 (10dB/step) Resistor
VIH VIL RATT-1
Attenuator 2 (2dB/step) Resistor
RATT-2
Max. Input Amplitude
Vin
Operating Oscillation Frequency DCO Output Current
fosc
PT2253A v 2.6
IDCO
CONDITION
Vcc=12V INH=0V OSC=12V
Attenuation Level is set to 0dB Attenuation Level is set to 0dB Bias Vcc/2 = 6V Fin=1KHz ATT=0dB
1 Step
Page 9
MIN.
TYP.
MAX.
6 -
1 -
12 3 10
0.8 x Vcc Vss - 0.3 25
50
Vcc + 0.3 0.2 x Vcc 70
kΩ
10
20
28
kΩ
-
-
4.0
Vrms
5
-
10k
Hz
70
100
140
uA
Revised October 1999
UNI T V mA uA
V
ANGUS ELECTRONICS COMPANY LIMITED Princeton Technology Corp.Tel: (852) 2345 0540 Fax: (852) 2345 9948 Web Site: www.angus.com.hk
Electronic Volume Controller IC
PT2253A
ELECTRICAL CHARACTERISTICS (Unless otherwise specified, Vcc = 6V, Vss = -6V, GND = 0V)
IN1 ~ OUT1 Characteristic Signal to Noise Ratio
Symbol S/N
Frequency Response
Fr
Noise Floor
NF
Total Harmonic Distortion
THD
Condition ATT=0dB Fin=1KHz Vin=1.0Vrms ATT=-10dB Fin=1KHz Vin=1.0Vp-p Vin=0V, ATT=0dB ATT=-10dB Fin=1KHz Vin=1.0Vrms
Max. 97
Unit dB
657
KHz
0.015
mv
0.010
%
IN2 ~ OUT2 Characteristic Signal to Noise Ratio
Symbol S/N
Frequency Response
Fr
Noise Floor
NF
Total Harmonic Distortion
THD
PT2253A v 2.6
Condition ATT = 0dB Fin=1KHz Vin=1.0Vrms ATT=-2dB Fin=1KHz Vin=1.0Vp-p Vin=0V ATT=0dB ATT=-2dB Fin=1KHz Vin=1.0Vrms
Page 10
Max. 95
Unit dB
1820
KHz
0.022
mv
0.009
%
Revised October 1999
ANGUS ELECTRONICS COMPANY LIMITED Princeton Technology Corp.Tel: (852) 2345 0540 Fax: (852) 2345 9948 Web Site: www.angus.com.hk
Electronic Volume Controller IC
PT2253A
APPLICATION CIRCUIT 1 Dual Power Supply (L-Channel Only) Vss
-6V + 4 1 LM358 _ 8 2
3 10uF
VDD
+
+6V 10uF
+
Vss
L-OUT1 R-OUT1
10uF +
INPUT GROUND
L-IN1 A-GND
10uF
L-IN2
+
OUTPUT
Vcc
R-IN1 A-GND R-IN2
L-OUT2 R-OUT2 INH
U/D
DCO
OSC
+ CX 4.7
PT2253A
10K
+ 1N4148
100K RS fosc =
RS
1 (0.7)(CX)( RX)
Page 11
33K RX 1N4148
3RX UP SW
PT2253A v 2.6
1uF
DOWN SW
Revised October 1999
ANGUS ELECTRONICS COMPANY LIMITED Princeton Technology Corp.Tel: (852) 2345 0540 Fax: (852) 2345 9948 Web Site: www.angus.com.hk
Electronic Volume Controller IC
PT2253A
APPLICATION CIRCUIT 2 Dual Power Supply (L-Channel Only) Vss
-6V 4 3 10uF
LM358
+
1
8
2
68pF VDD
+6V 10uF
0.15uF
+
51K Vss
10uF
L-OUT1 R-OUT1
+
INPUT GROUND
L-IN1 A-GND
10uF
L-IN2
+
OUTPUT
110K
Vcc
R-IN1 A-GND R-IN2
L-OUT2 R-OUT2 INH
U/D
DCO
OSC
CX 4.7
PT2253A
10K
1N4148
100K RS fosc =
RS
1 (0.7)(CX)( RX)
1uF
33K RX 1N4148
3RX UP SW
DOWN SW
Note: Since the Buffer Amp between Att-1 and Att-2 is already 10dB Voltage Gain, higher input level may cause OP Amp’s Output Clipping. To avoid unwanted distortion, the input signal level applied at IN-1 should not be over 1 Vrms.
PT2253A v 2.6
Page 12
Revised October 1999
Page 13
Vcc
Output (Left Channel)
Input (Left Channel)
10K
10K
Vcc
2
8 1 + - LM358 4
+ 100uf
C3
C1
10uf
+
10uf
+
Vcc
R-IN2
OSC
DCO
PT2253A
U/D
INH
R-OUT2
L-IN2 L-OUT2
A-GND
R-IN1
R-OUT1
A-GND
L-IN1
L-OUT1
Vss
Vcc
10uf C2
0.1uf
Up Key
100K
10uf C4
4.7uf +
+
PT2253A v 2.6 +
3
2
2
IN4148 1 2
33K
IN4148
2
2
2
1
6
5
+ 1uf
8 7 + - LM358 4
Vcc (6 ~ 12V)
Output (Right Channel)
Input (Right Channel)
ANGUS ELECTRONICS COMPANY LIMITED
Princeton Technology Corp.Tel: (852) 2345 0540 Fax: (852) 2345 9948 Web Site: www.angus.com.hk
Electronic Volume Controller IC PT2253A
APPLICATION CIRCUIT 3
Single Power Supply
Revised October 1999
ANGUS ELECTRONICS COMPANY LIMITED Princeton Technology Corp.Tel: (852) 2345 0540 Fax: (852) 2345 9948 Web Site: www.angus.com.hk
Electronic Volume Controller IC
PT2253A
APPLICATION CIRCUIT 4
Output (Right Channel)
110K
68pF
7
2
2
2
2
2
1 Up Key
10uf
Vcc OSC DCO
C3
+
PT2253A
U/D INH
R-IN2
R-OUT2 L-OUT2
L-IN2
10uf
A-GND
R-IN1 L-IN1 10uf
+ 100uf
68pF
110K
10K
Vcc
Output (Left Channel)
Input (Left Channel)
51K
0.15uf
10K
Vcc
8 3 + 2 - LM358 4
1
C1
+
Vcc
R-OUT1 L-OUT1
Vss
+ A-GND
0.1uf
+
100K
+ 4.7uf
C4
C2
10uf
33K
IN4148
1
0.15uf 51K
IN4148
+
1uf
8 5 + 6 LM358 4
Vcc (6 ~ 12V)
Input (Right Channel)
Single Power Supply
Note: Since the Buffer Amp between Att-1 and Att-2 is already 10dB Voltage Gain, higher input level may cause OP Amp’s Output Clipping. To avoid unwanted distortion, the input signal level applied at IN-1 should not be over 1 Vrms. PT2253A v 2.6
Page 14
Revised October 1999
ANGUS ELECTRONICS COMPANY LIMITED Princeton Technology Corp.Tel: (852) 2345 0540 Fax: (852) 2345 9948 Web Site: www.angus.com.hk
Electronic Volume Controller IC
PT2253A
ORDER INFORMATION Valid Part Number PT2253A
Package Type 16 Pins, DIP
PACKAGE INFORMATION 16 Pins, DIP Package
PT2253A v 2.6
Symbol
Dimension in Mil
A
750
B
65
C
55
Page 15
Revised October 1999