AN7195K

ICs for Audio Common Use

10

s Technical Information (continued)

[2] Application note (continued)

8. Mute Function

1) The mute-on/off is possible by making pin 7 (the muting terminal) high or low.

2) The muting circuit is as shown in figure 6. The amplifier gain including attenuator block is given in the

following equation :

Original gain

Mute-off : approx. 1 V or less

Mute-on : approx. 3 V or more

Figure 6

4) Attack time and recovery time can be changed by the external CR of pin 7. For recommended circuits (In

figure 6 4.7 k

Ω,10 µF), the above mentioned times are as follows :

Attack time

: Approx. 30 ms

Recovery time : Approx. 40 ms

microcomputer (5 V), (that is, 13.2 V separate power supply), it is necessary to change CR values because the

above times change.

5) When the attack time and recovery time are set at 20 ms or less, pay attention to the IC with larger output

offset because it may release the shock noise.

9. Voltage gain

The voltage gain is fixed at 40 dB and can not be changed by the addition of an external resistor.

5 k

Ω

7

4.7 k

Ω

5 V

0 V

10

µF

Output stage

Input

Output stage

Attenuator block

Mute/off

Mute/on