LA4445
Description of External Parts
C1 (C2) :
C3 (C4) :
C5 (C6) :
C7 (C8) :
C9 :
Feedback capacitor
Low cutoff frequency f depends on this feedback capacitor. Increasing the capacitor value makes the
starting time later
Bootstrap capacitor
If the capacitor value is decreased, the output at low frequencies goes lower.
(Recommended value : 47µF min.)
L
Oscillation blocking capacitor
Polyester film capacitor, being excellent in temperature characteristic, frequency characteristic, is
recommended. The capacitor value can be reduced to 0.047µF depending on the stability of the board.
Output capacitor
The low cutoff frequency depends on this output capacitor. In bridge connection applications the output
capacitor must be normally connected.
Decoupling capacitor
Used for the ripple filter. Since the rejection effect is saturated at a certain capacitor value, it is mean-
ingless to increase the capacitor value more than needed. This capacitor, being also used for the time
constant of the pop noise preventer, affects the starting time. Too small a capacitor value makes the pop
noise level higher.
C10 :
Power source capacitor.
R1 (R2) :
Oscillation blocking filter resistor.
IC Application
1. V.G. can be reduced by connecting R ’ to the N.F. pin (pins 1, 6)
NF
V.G. is calculated by the following formula.
VG=20log R / (R +R ’)
f
NF
NF
where R =20kΩ, R =50Ω
f
NF
The usable lower limit of VG is 36dB or thereabouts. When setting VG, oscillation and high cutoff frequency f
H
must be considered.
2. External audio muting method
Proper Cares in Using IC
· If the IC is used in the vicinity of the maximum rating, even a slight variation in conditions may cause the maximum
rating to be exceeded, thereby leading to breakdown. Allow an ample margin of variation for supply voltage, etc. and
use the IC in the range where the maximum ratings is not exceeded.
· Printed circuit board
When making the board, refer to the sample printed circuit pattern. No feedback loop must be formed between input and
output. Both Pins GND and Power GND must be shorted at the root of IC pin so that the common impedance can be
reduced.
· Others
The radiator fin on the package must be normally connected to GND.
Some plug jacks to be used for connecting to the external speaker are such that both poles are shorted once when
connecting. In this case, the load is shorted, which may break down the IC.
No.1277–4/7
SANYO [ SANYO SEMICON DEVICE ]
