Test Circuit

1. Features and Usage Notes

• Pin 12 is the standby pin. The IC operates when a voltage of 2 V or higher is applied through the external resistor

R1. Note that the maximum influx current to pin 12 is 500 µA.

• Changing the voltage gain

The voltage gain VG can be lowered by connecting an external resistor in series between the NF pin (pins 8 and

VG = 20 log

However, since the IC may oscillate if VG is 30 dB or lower, use a VG of 36 dB or higher.

• The LA4450 includes a thermal protection circuit to prevent damage to or destruction of the IC due to abnormal

overheating. As a result, the output may be attenuated or cut off if the application heat sinking is inadequate.

• The LA4450 includes an overvoltage protection circuit to protect the IC against power supply surges and abnormal

voltages. This circuit has hysteresis characteristics: it operates at between 39 and 40 V, and recovers at around 34 V.

• Although the LA4450 includes a current limiter circuit to prevent damage due to abnormal currents, care must still

be exercised to prevent load shorts and other excessive current conditions.

30 k

Ω

No. 4090-3/7

LA4450

Unit (resistance :

Ω, capacitance : F)