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PT2256 V1.7

- 11 -

August, 2006

Electronic Volume Controller IC

PT2256

APPLICATION CIRCUIT

SINGLE POWER SUPPLY (NO LOUDNESS AND NO BACKUP CIRCUIT)

L-Ch Output

R-Ch Output

R-Ch Input

L-Ch Input

Rx

Cx

VSS

OUT1

IN1

LT1

AGND

/UP

/DN

OSC

VDD

OUT2

IN2

LT2

AGND

DCO

/INH

/RST

PT2256

100K

3.9K

3.9K

10 F

µ

10 F

µ

UP Key

Down Key

0.1 F

µ

10 F

µ

10 F

µ

0.1 F

µ

10K

10K

100 F

µ

VDD (4.5 to 12V)

+

+

+

+

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

Cx

Fosc

Rx

Cx

Fosc

33K

1.0µF

34.1Hz

33K

1.0µF

34.1Hz

33K

2.2µF

17.8Hz

51K

1.0µF

22.7Hz

33K

10µF

3.4Hz

100K

1.0µF

11.8Hz