an7198z Panasonic Corporation of North America, an7198z Datasheet - Page 14

• Manufacturer Part Number: an7198z
• Description: Dual 20 W Btl Power Ic For Car Audio
• Manufacturer: Panasonic Corporation of North America

AN7198Z
14
3. Application note (continued)
6) Cooling fin
7) Shock noise
8) Mute function
Technical Information (continued)
(1) The cooling fin is not connected with GND terminal by using Au wire. Only pin 8 is electrically connected
(2) Always attach an outside heat sink to the cooling fin. The cooling fin must be fastened onto a chassis for use.
(3) Do not give the cooling fin any potential other than the GND potential. Otherwise, it may cause breakdown.
(4) Connection of the cooling fin with GND can reduce the incoming noise hum. (It is unnecessary to connect
(1) STB on/off
(2) Mute on/off
(1) The mute-On/Off is possible by making pin 7 (the muting terminal) high or to low.
(2) The muting circuit is as shown in Figure 7. The amplifier gain including attenuator block is given in the
(3) The threshold voltage of V
through the substrate.
Otherwise, IC lead failure may occur.
with GND in use, but connect it with the power GND when the cooling fin is connected with GND)
may make a slight shock noise. In such a case, insert a capacitor of approx. 0.01 F between the standby
terminal and GND.
following equation:
G
From the above equation, the amplifier gain can be made as 0 time by setting I
Mute-off
Mute-on
V
V
MUTE
Turn on the mute circuit when switching over to the standby.
No shock noise is released when the mute on state. However, the changeover switch of the standby terminal
No shock noise is released. Refer to the section on the mute function.
I
I
1
2
5 V
0 V
Mute/off
50
Mute/on
approx. 3 V or more
approx. 1 V or less
Original gain
22 k
1 F
MUTE
Input
is as follows:
7
Figure 7
200
ICs for Audio Common Use
Attenuator block
I
I
1
1
I
I
1
2
1
at 0 mA at muting.
approx. 120 A
approx. 120 A
I
I
2
2
Output stage
Output stage