STK4065

No. 2148—4/9

In normal applications, since a heat sink is mounted on

the IC, the substrate temperature does not rise up to a

temperature at which the input signal is turned OFF

completely, but is saturated at a certain temperature.

When load short occurs with a heat sink of 4.5

°C/W

mounted, the substrate temperature is saturated at

approximately 160

°C.

Tj in this state is as high as 170

°C, which obviously

exceeds the maximum rating.

As mentioned above, the thermal protector is designed

to prevent the IC from breaking down in a short time

when abnormal temperature rise occurs, but is not

intended to protect the IC from damage for a long time

when abnormal temperature rise occurs.

(3) Others

a) Excessive input

When an excessive input of 1.5 Vrms (f = 1kHz) or

greater is applied to the input pin, the input channel DC

balance of the input monolithic amplifier is disturbed,

the output is cut off, and DC voltage is developed on

the output pins, damaging the speaker. Be careful not

to permit an input of 1.5Vrms (f = 1kHz) or greater to

be applied.

b) Parasitic oscillation

The STK4065 has 2.2

Ω, 0.47µF across the V

and the bootstrap pins for phase compensation. This

makes it necessary for the power line to be extended

close to the bootstrap pins for both the inverting ampli-

fier and the non-inverting amplifier. Too long a power

line may cause parasitic oscillation to occur at low

temperatures. If so, connect a capacitor of approxi-

mately 0.1

µF across the tip of the power line and GND

to decrease AC impedance of the power line.

c) Inverse application of supply voltage

The STK4065 contains no protector against inverse

application of supply voltage. If there is a possibility

that inverse application of supply voltage may occur,

connect the protector externally.

d) Power switch-OFF mode

Do not connect pin 1 direct to GND, otherwise the IC

may be broken down.

When connecting pin 1 to GND, connect a resistor of

100

Ω or greater in series with pin 1 or connect a diode

across pin 10 and pin 1.