This is one of the semiconductor types. This part name is LA4440.
This product has 6W 2-Channel, Bridge 19W(typ) Power Amplifier functions.
Manufacturers of product is ON Semiconductor.
Image and pinout :
LA4440 PDF Datasheet
Some of the text files within the PDF file
1. Built-in 2 channels (dual) enabling use in stereo and bridge amplifier applications.
Dual : 6W2 (typ), Bridge : 19W (typ)
2. Minimum number of external parts required.
3. Small pop noise at the time of power supply ON/OFF and good starting balance.
4. Good ripple rejection : 46dB (typ)
5. Good channel separation.
6. Small residual noise (Rg=0).
7. Low distortion over a wide range from low frequencies to high frequencies.
8. Easy to design radiator fin.
9. Built-in audio muting function.
10. Built-in protectors.
a. Thermal protector
b. Overvoltage, surge voltage
[ … ]
Please refer to the file for details.