ICs for Audio Common Use
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Technical Information (continued)
•
Power-off pop-noise countermeaasure (for study consideration only)
AN5270
To prevent power-off shock noise, please ensure that V
CC2
(18 V) declines faster than V
CC1
(12 V). In addition, to
ensure that V
CC1
variation will not cause any 'pop' , one suggested countermeasure is to connect a condenser between
Pin6 and Pin9 (e.g. 47
µF,
use non-polarity type if possible).
RF
6
C6
47
µF
Cpop
47
µF
NP
V
CC2
9
2200
µF
Fig. One suggested counter-measure against power-off 'pop' for AN5270.
This effect of Cpop is to discharge C6 gradually as soon as power is switched off.
However, it must be noted that the necessity of this countermeasure is dependent upon the set design and other timing
considerations.
•
THD improvement (for study consideration only)
1
6
47
µF
C6
Fig. THD improvement circuit.
Instead of connecting the negative terminal of C6 to ground, when that terminal is connected to Pin1, it is noticed that
THD is improved considerably.
9
PANASONIC [ PANASONIC SEMICONDUCTOR ]
