an7191nz Panasonic Corporation of North America, an7191nz Datasheet - Page 14

• Manufacturer Part Number: an7191nz
• Description: Dual 20 W Btl Audio Power Amplifier
• Manufacturer: Panasonic Corporation of North America

AN7191NZ
14
[2] Application note (continued)
7. Shock noise
8. Mute function
9. Voltage gain
Technical Information (continued)
1) STB on/off
2) Mute on/off
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
3) The threshold voltage of V
4) Attack time and recovery time can be changed by the external CR of pin 7. For recommended circuits (figure
5) When the attack time and recovery time are set at 20 ms or less, pay attention to the IC with larger output
V
shock noise. In such a case, insert a capacitor of approx. 0.01 F between the standby terminal and GND.
following equation :
From the above equation, the amplifier gain can be made as 0 time by setting I
7. 4.7k , 10 F), the above mentioned times are as follows :
However, the control voltage of V
microcomputer (5 V), (13.2 V separate power supply), it is necessary to change CR values because the above
times change.
offset because it may release the shock noise.
The voltage gain is fixed at 34 dB and can not be changed by the addition of an external resistor.
MUTE
No shock noise is released. However, the changeover switch of the standby terminal may make a slight
No shock noise is released. Refer to the section on the mute function.
G
Mute-off : Approx. 1 V or less
Mute-on : Approx. 3 V or less
Attack time
Recovery time : Approx. 40 ms
5 V
0 V
V
Mute/Off
I
I
Mute/On
1
2
50
Original gain
4.7 k
: Approx. 30 ms
10 F
MUTE
Input
is as follows :
7
MUTE
is assumed to be 5 V. When it is not directly controlled by
5 k
Figure 6
ICs for Audio Common Use
Attenuator block
I
I
1
1
1
at 0 mA in muting.
g
I
I
1
2
I
I
2
2
approx. 120 A
approx. 120 A
Output stage
Output stage