
NJU3555
NJU3555
NJU8753
-7 -
Ver.2003-09-26
TYPICAL APPLICATION CIRCUIT
Note 5) De-coupling capacitors must be connected between each power supply pin and GND.
The capacity value should be adjusted on the application circuit and the operation temperature. It may
malfunction if capacity value is small.
Note 6) The power supply for VDDO require fast driving response performance such as a switching regulator for
better THD.
THD performance becomes worse by ripple if the capacity of De-coupling capacitors is small.
Note 7)
The above circuit shows only application example and does not guarantee the any electrical
characteristics. Therefore, please test the circuit carefully to fit your application.
The cutoff frequency of the LC filter influences the quality of sound.
The Q factor of the LC filter must be less than “1”. Otherwise, the operating current increase when the
frequency of input signal is closed to the cutoff frequency.
Note 8) The transition time for EN1 and EN2 signals must be less than 100
µs. Otherwise, a malfunction may
be occurred.
Note 9) (1)-(28) indicates pin number.
Piezo Speaker
Figure 2. Application Circuit example
OUTP(20)
OUTN(16)
VDD(28)
VSS(27)
0.1µF
10µF
VDD
IN(26)
COM(25)
EN1(24)
10µF
47µH
2µF
47uH
4.7Ω
4.7Ω
IN
2.2µF
22000pF
2.4kΩ
VDDO(14,15)
VOUT(10)
VBAT
VSS(17,19)
FB(4)
LX(8,9)
TEST1(1)
TEST2(23)
VDDO(21,22)
Schottky diode
(IF=1A,VF=0.45V)
R1
R2
2MΩ
330kΩ
0.1µF
10µF
TEST3(2)
EN2(12)
VREG(3)
VSS(5)
0.1µF
10µF
VDD
0.1µF
0.1µF
22µH(DCR=0.5
Ω)
22µF
VR(11)
VSS1(6,7)
0.1µF
[CAUTION]
The specifications on this databook are only
given for information , without any guarantee
as regards either mistakes or omissions. The
application circuits in this databook are
described only to show representative usages
of the product and not intended for the
guarantee or permission of any right including
the industrial rights.