TA8221AHQ / ALQ
(Precaution 2)
If the falling time constant of the VCC line is large (the fall is gentle), the pop noise may become worse.
In this case, it is possible to prevent the pop noise from beoming worse by reducing the capacity of "ripple rapid
discharging circuit at the time of VCC off" accordign to the following steps :
(a) Short pin(1) (mute terminal) and pin(8) (ripple terminal).
(b) Increase the capacity of ripple capacitor of pin(8).
However, it shall be kept in mind that the time for turning the power on becomes longer as the result of step
(b).
7. External parts list and description
Sym−
bol
Recom−
mended
Value
Feature
C1
4.7µF
DC blocking
C2
47µF
Feedback
condenser
Influence
Smaller Than
Recommended Value
Larger Than
Recommended Value
Related to pop noise at VCC→on.
Related to pop noise at VCC→on.
Determination of low cut−off frequency.
C2 =
1
2π・fL・Rf
Remarks
Related to gain.
Refer to item 4.
C3
220µF
Ripple
reduction
Time constant is small
at VCC→on or off.
Time constant is large
at VCC→on or off.
C4
0.12µF
Oscillation
prevention
Made liable to
oscillate.
Oscillation allowance
Refer to item 3.
For filtering power supply hum and ripple.
C5
1000µF
Ripple filter
Large at using AC rectified power supply.
Small at using DC power supply.
C6
1000PF
Oscillation
prevention
Oscillation allowance improved.
Noise reduction
Refer to item 3.
6
2006-04-28