LA4598 Datasheet, PDF (8/9 Pages) Sanyo Semicon Device – Two-channel Power Amplifier for Radio Cassette Players (No Heat Sink Needed during 9 V Operation)

LA4598
Features and Usage Notes
1. VG can be lowered by adding an R_NF’ to the NF pins (pins 5 and 11).
Calculated as follows:
VG = 20log R_f/(R_NF + R_NF’)
The IC contains R_f = 20 kΩ, R_NF = 62 Ω.
However, the following must be noted:
a) If R_NF’ is added, the ripple bypass effect due to the NF capacitor will worsen, resulting in a worsening of ripple
rejection.
b) Oscillation stability requires, use at 40 dB or less to be avoided.
2. Pin 9 is intended for standby. It is used in conjunction with power supply pin 4. However, it should be noted that when
power supply pin 9 and pin 4 are used for separate systems, the output power is affected by the pin 9 supply voltage.
3. It is recommendable to use no input capacitor. However when rubbing noise generated by the volume control is offencive to
the ear, an input capacitor must be inserted.
4. Extreme caution must be exercised when the IC is used in the vincity of the maximum ratings, since even a slight variation
in conditions may cause the maximum ratings to be exceeded, thereby leading to breakdown.
5. When making the board, refer to the sample printed circuit pattern. No feedback loop must be formed between input and
output. Thick and short wiring is required so that no common resistance exists between the preamplifier GND and power
amplifier GND.
6. Addition of components as shown below enables use without introducing an increased distortion at V_CC of up to
approximately 4.5 V. A capacitor of 470 µF is inserted against pop noise.
Proper Cares in Mounting a Radiator Fin
1. The tightening torque should be in a range from 4 to 6 kg.cm.
2. The spacing between the screw holes of the radiator fin must match the spacing between the screw holes of the IC. With case
outline dimensions L and R referred to, the screws must be tightened with the distance between them as close to each other
as possible.
3. The screws to be used must have a head equivalent to the one of truss machine screw or binder machine screw defined by
JIS. Washers must also be used to protect the IC case.
4. No foreign matter such as cutting particles should exist between heat sink and radiator fin. When applying grease on the
junction surface, it must be applied uniformly on the whole surface.
5. IC lead pins should be soldered to the printed circuit board after the radiator fin is mounted on the IC.
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