M61510AFP

Rev.1.00, Aug.07.2003, page 12 of 22

Explanation of Functions

(1) Main volume

This IC includes two independent low-distortion, low-noise electronic volume systems. The attenuation can be set from

0 dB to -

∞ dB in 1 dB steps.

Also, the attenuation can be set between 0 and -16 dB for the first stage, and between 0 and -64 dB for the second stage,

and both can be controlled independently.

Equivalent circuit diagram for main volumes 1, 2

VOL IN1,2

18,25 pin

VOL OUT1,2

19,24 pin

0dB to -64dB:1dB steps

+

-

Tone and

surround

block

0dB to -16dB:

in 1dB steps

VSELB OUT1,2

17,26 pin

Volume input

selector A

+

-

Volume input

selector B

Switching

noise-reduction capacitor

VSELA OUT1,2

17,26 pin

(2) Input selector, input volume

Two channels of 5-input selectors, and two channels of input volume controls for input trimmers, are incorporated. The

D and E inputs of the input selectors can select either 0 dB or -8 dB input levels for an input resistance of 12 k

Ω using

the ATT switch. The input volume can be set between 0 and -14 dB in 2 dB steps.

0dB to -14dB: 2dB steps

To volume input selector A

E input ATT SW

(0dB/-8dB)

100k

100k

100k

A

B

C

D

E

50k

9.5k

Note 1) The input resistance for the D and E inputs changes

according to the ATT SW setting as follows.

D, E input ATT

-8dB : 20 k

Ω (TYP)

0dB : 60 k

Ω (TYP)

Note 2) When the input selector is A-C or E or is ALL OFF, the D input ATT SW

is set to -8 dB. When the input selector is A-D or is ALL OFF,

the E input ATT SW is set to -8 dB.

9.5k

D input ATT SW

(0dB/-8dB)

12k

12k

Note 4) When the external 12 k

Ω resistance is eliminated, the D and E input ATT amounts are set as follows.

0dBsetting: 1.87dB

-8dBsetting: 0dB

Note 3) The D and E input ATT amounts shown are the values when a D and E input resistance

Rin=12 k

Ω is connected.