LA4632 查看數據表（PDF） - SANYO -> Panasonic
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LA4632 Datasheet PDF : 8 Pages
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LA4632
Pin 6 IC internal equivalent circuit
When an voltage of +5 V is applied to the mute pin through the
external 15 kΩ resistor, the pin 6 voltage becomes about 1.85 V. (The
15kΩ Imute
2kΩ
+5V
6
Mute pin applied
voltage
muting function activation level in the specifications is 1.7 V
minimum.) The pin 6 influx current (Imute) at this time will be
roughly 210 µA.
Although it is possible to change the mute pin applied voltage or the
values of the mute pin external components, if the pin 6 voltage (and
pin 6 influx current) is too high, or if the pin 6 external component
time constant is too short, the amplitude of impulse noise in the
system may rise. This phenomenon must be taken into account when
Other items
designing this circuit.
Standby function
Pin 5 IC internal equivalent circuit
Use ISTB = up to 500µA
as an initial target.
RSTB
15kΩ
5
2VBE
Standby pin
applied voltage
The IC's pin 5 is a standby pin. The amplifier is turned on when the
voltage applied to this pin is about 2 V or higher. (The value in the
specifications is 2.5 V minimum.) If a voltage of +5 V is directly
applied to the standby pin, the pin 5 influx current will be about 230
µA.
ISTB =
5 V – 2 VBE (about 1.55 V)
15 kΩ
= 230 µA
If a voltage that exceeds the upper limit voltage given in the
specifications (10 V) is applied as the standby pin voltage, calculate a
value for an external resistor RSTB from the following formula so that
the pin 5 influx current does not increase excessively (use a value of under about 500 µA as the initial target value).
Usage Notes
RSTB =
Applied voltage - 2VBE (about 1.55 V)
ISTB (Under 500 µA)
– 15 kΩ
Notes on the Maximum Ratings
If this IC is used in the vicinity of the maximum ratings, even the slightest fluctuations in the operating conditions could
cause those ratings to be exceeded, making the destruction of the device possible. Applications must be designed with
adequate margins in the supply voltage and other parameters so that the devices is always used in ranges that do not
exceed the maximum ratings.
Notes on Protection Circuits
While the LA4632 provides a full complement of built-in protection circuits, care is required in their use. In particular,
be careful not to inadvertently short IC pins to each other.
[Notes on the short to power, short to ground, and load shorting protection circuit]
• This protection circuit operates when an abnormal short such as a short to power (a short between an output and
VCC), a short to ground (a short between an output and ground), or a load short (a short between the output ± sides)
occurs. Although this circuit may not operate when the VCC voltage is under about 9 V, the thermal protection
circuit is thought adequate to protect the IC in that case.
• This protection circuit is the type that continues to operate while the above listed short state continues and recovers
automatically as soon as the abnormality is resolved. However, there are cases where, depending on the operating
conditions, the protection circuit locks and the protection operation continues. In these cases, the protection circuit
can be cleared by switching to standby mode or cutting and reapplying power.
• Note that if the output is shorted to power in the state where the IC is in the standby state (amplifier operation is
turned off) and VCC is over about 20 V, an offset may occur between the plus and minus outputs. If a load is
connected in this state, current may flow in through the load and the IC may be destroyed.
• In the following usage conditions, a symptom in which the output audio is cut off at high outputs due to protection
circuit operation. Depending on the end product specifications, it may be necessary to check for this phenomenon.
• Situations where both channels are operating in a manner that the IOPeak per channel exceeds 1 A at low RL (high
loads) and high VCC (The higher the chip temperature the easier it is for this phenomenon to occur.)
The "Allowable operating supply voltage range (VCC op)" item in the operating conditions specifications provides
specific target operating conditions so that the above phenomenon will not occur under severe usage conditions
(high temperatures, high outputs. (See the different VCC op ranges for different RL values.)
No.8178-5/8
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