This part is a kind of semiconductor called STA335BWSQS.

Function of this product has high-efficiency digital audio system.

Manufacturers : ST Microelectronics

Image and pinout :

Some of the text within the PDF file :

STA335BWSQS 2.1-channel, high-efficiency digital audio system with QSound QHD® PowerSSO-36 slug down Features ! Wide supply voltage range – 4.5 V to 21.5 V operation – 23-V absolute maximum rating 3 power output configurations – 2 channels of ternary PWM (stereo mode) (2 x 20 W into 8 Ω at 18 V) – 3 channels - left, right using binary and LFE using ternary PWM (2.1 mode) (2 x 9 W + 1 x 20 W into 2 x 4 Ω, 1 x 8 Ω at 18 V) – 2 channels of ternary PWM (2 x 20 W) + stereo line out ternary 2.1 channels of 24-bit DDX® 100-dB SNR and dynamic range Selectable 32 kHz to 192 kHz input sample rates I2C control with selectable device address Digital gain/attenuation +48 dB to -80 dB in 0.5-dB steps Soft volume update Individual channel and master gain/attenuati [ ... ]

STA335BWSQS PDF Datasheet Download