LA4809M

Continued from preceding page.

When the standby function is not to be used, Pin 3 may be interlocked with power supply as shown in Fig.7. However,

due care must be taken in this case because such interlock makes the effectiveness of the pop noise reduction circuit

null, resulting in extremely large pop noise at a time of rising and falling. There are also methods to reduce the pop

noise by using two capacitors as shown in Fig.8. If pop noise is to be suppressed sufficiently, CPU control of the

standby pin is recommended.

Note that the approximate inrush current; I3 into the standby pin is calculated as follows :

Pin 3 inrush current (unit : A) : I3 = (5

No.A1569-8/15

VCC

Rst

Fig.7

Fig.8

10. Operating power supply voltage range

The applicable power supply voltage range varies depending on the setting conditions of the maximum output power

value. Use this range while taking into account the Pin 2 voltage. As a guideline, the supply voltage at the lowest point

to be used must be two times the Pin 2 voltage.

Note that the minimum operating supply voltage must be 3.6V.

mode-B

⇒ VCC op = 6.2V to 17V

mode-A

⇒ VCC op = 4.2V to 17V

At change of the output power value due to external resistance

⇒ VCC op = 2 × V2 to 17V (V2 ⇒ Pin 2

voltage)

11. Handling of NC pins (Pins 5, 8, and 11)

NC pins are not connected to anything internally and may be left in the OPEN state. To enhance the heat sink effect as

much as possible, connection of NC pins to the GND line is recommended.

In particular, Pin 5 should be connected to the GND line so as to protect Pin 4 (the first output).

If the pins 4 and 5 section and the pins 5 and 6 section are bridged with solder simultaneously, the output pin enters the

powering (short to power) state, allowing the large current to flow into the output pin, resulting in deterioration or

damage of internal elements. Risk of deterioration or damage may be reduced when Pin 5 is connected to GND. When

the output pin voltage is about 0.7V or less, drive and power stages of the power amplifier circuit used becomes

inoperable. In this context, the protection in case of ground fault is provided.

12. Heat protective circuit

The heat protective circuit is incorporated in IC and can reduce the risk of damage/deterioration in case of abnormal

heat generation due to certain reasons. This protective circuit is activated when the junction temperature : Ti of the chip

in IC increases to about 160

°C, shutting OFF current supply to the power amplifier. The signal is not output anymore.

When the chip temperature lowers (to about 130

°C), the circuit is automatically reset.

Note that this circuit is not always capable of preventing damage/deterioration and should be handled with utmost care.

In case of abnormal heating, turn OFF power supply immediately and identify the probable causes.

13. Short-circuit between pins

Power ON while leaving the pins in the short-circuit state may cause deterioration or damage. When installing IC to the

substrate, check if pins are short-circuited with solder before turning power supply ON.

14. Load short-circuit

Leaving the loads in the short-circuit state over a long period of time may cause deterioration or damage. Never

short-circuit loads.

15. Maximum rating

When the product is used near the maximum rating, even the smallest change in the conditions may cause exceeding of

the maximum rating, possibly leading to the fracture accident. Take the sufficient fluctuation margin for the supply

voltage and always use the product within a range never exceeding the maximum rating. The package used for this IC

has the low heat sink effect as a single unit. When the working supply voltage is high, solder the backside heat sink pad

to ensure sufficient heat sink performance with copper foil of printed circuit board.

VCC

VCC

Rst

6

STBY

3

VCC

6

STBY

+

Cst2

3

+

Cst1