Tel:886-2-66296288
Fax:886-2-29174598
URL:http://www.princeton.com.tw
Electronic Volume Controller IC
PT2256
DESCRIPTION
PT2256 is an electronic volume controller IC utilizing CMOS Technology specially designed for use on
audio equipment. It has 2 built-in channels making it ideally suitable for mono and stereo sound
applications. PT2256 provides the Loudness Function, a wide frequency response range and a very
low total harmonic distortion, thereby guaranteeing a highly effective and reliable performance. It is
housed in 16-pin DIP or SOP package and is functionally compatible with TC9235P. Pin assignments
and application circuit are optimized for low cost advantages and easy PCB Layout.
FEATURES
•
•
•
•
•
•
•
•
•
•
CMOS technology
Low power consumption
Least external components
2 channels in the same chip
0dB to -78dB attenuation can be controlled by up and down pin
20dB tap for loudness circuit
Built-in DC output circuit (8 levels) for volume level metering
Wide frequency response range
Low total harmonic distortion
Available in 16 pins DIP or SOP
APPLICATION
•
Audio equipment volume control
PT2256 V1.7
-1-
August, 2006
Tel:886-2-66296288
Fax:886-2-29174598
URL:http://www.princeton.com.tw
Electronic Volume Controller IC
PT2256
BLOCK DIAGRAM
VS S
OUT1
IN 1
LT 1
AG N D
VD D
OUT2
IN 2
LT 2
AG N D
D e co d e r
/U P
/D N
O SC
U p /D o w n
C o u n te r
C o n tr o l
D/A Con ve rte r
DCO
/I N H
/R ST
PT2256 V1.7
-2-
August, 2006
Tel:886-2-66296288
Fax:886-2-29174598
URL:http://www.princeton.com.tw
Electronic Volume Controller IC
PT2256
APPLICATION CIRCUIT
SINGLE POWER SUPPLY (NO LOUDNESS AND NO BACKUP CIRCUIT)
VDD (4.5 to 12V)
0.1
µ
F
L-Ch Output
L-Ch Input
10
µ
F
10
µ
F
3.9K
3.9K
UP Key
Down Key
Rx
100K
+
Cx
PT2256
0.1
µ
F
10K
Note:
Modifying the values of Rx and Cx affects the Oscillator Frequency of the IC. If the Fosc value is big,
then the volume control change is fast. Likewise, if the Fosc value is small, the volume control change
is slow. It is suggested that Rx=33K, Cx=2.2µF.
The table for the Rx, Cx and Fosc values are given below:
Rx
33K
33K
33K
Cx
1.0µF
2.2µF
10µF
Fosc
34.1Hz
17.8Hz
3.4Hz
Rx
33K
51K
100K
Cx
1.0µF
1.0µF
1.0µF
Fosc
34.1Hz
22.7Hz
11.8Hz
PT2256 V1.7
- 11 -
+
+
10K
10
µ
F
+
+
VDD
VSS
OUT1 OUT2
IN1
IN2
LT1
LT2
AGND AGND
/UP
DCO
/INH
/DN
/RST
OSC
10
µ
F
R-Ch Output
R-Ch Input
+
100
µ
F
August, 2006
Tel:886-2-66296288
Fax:886-2-29174598
URL:http://www.princeton.com.tw
Electronic Volume Controller IC
PT2256
INCLUDING LOUDNESS BUT NO BACKUP CIRCUIT
VDD (4.5 to 12V)
0.1
µ
F
L-Ch Output
L-Ch Input
10
µ
F
0.1
µ
F
10
µ
F
820Ω
820Ω
8.2nF 820Ω
820Ω
UP Key
Down Key
Rx
8.2nF
0.1
µ
F
10K
100K
+
Cx
PT2256
0.1
µ
F
10K
Note:
Modifying the values of Rx and Cx affects the Oscillator Frequency of the IC. If the Fosc value is big,
then the volume control change is fast. Likewise, if the Fosc value is small, the volume control change
is slow. It is suggested that Rx=33K, Cx=2.2µF.
The table for the Rx, Cx and Fosc values are given below.
Rx
33K
33K
33K
Cx
1.0µF
2.2µF
10µF
Fosc
34.1Hz
17.8Hz
3.4Hz
Rx
33K
51K
100K
Cx
1.0µF
1.0µF
1.0µF
Fosc
34.1Hz
22.7Hz
11.8Hz
PT2256 V1.7
- 12 -
+
+
10
µ
F
+
+
VDD
VSS
OUT1 OUT2
IN1
IN2
LT1
LT2
AGND AGND
/UP
DCO
/INH
/DN
/RST
OSC
10
µ
F
R-Ch Output
R-Ch Input
+
100
µ
F
August, 2006
Tel:886-2-66296288
Fax:886-2-29174598
URL:http://www.princeton.com.tw
Electronic Volume Controller IC
PT2256
ORDER INFORMATION
Part Number
PT2256
PT2256-S
PT2256-SN
PT2256 (L)
PT2256-S (L)
PT2256-SN (L)
Package
16 Pins, DIP, 300mil
16 Pins, SOP, 300mil
16 Pins, SOP, 150mil
16 Pins, DIP, 300mil
16 Pins, SOP, 300mil
16 Pins, SOP, 150mil
Top Code
PT2256
PT2256-S
PT2256-SN
PT2256
PT2256-S
PT2256-SN
Notes:
1. (L), (C) or (S) = Lead Free.
2. The Lead Free mark is put in front of the date code.
PT2256 V1.7
- 13 -
August, 2006
FPGA/CPLD
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