This part is a kind of semiconductor called STK412-170.

Function of this product has AF Power Amplifier.

Manufacturers : Sanyo Semiconductor

Image and pinout :

Some of the text within the PDF file :

Ordering number : ENN7251 Thick-Film Hybrid IC STK412-170 Two-Channel Shift Power Supply Audio Power Amplifier ICs 180W + 180 W Overview The STK412-000 series are class H audio power amplifier hybrid ICs that feature a built-in shift power supply circuit. These ICs provide high efficiency audio power amplification by controlling (switching) the supply voltage supplied to the power transistors according to the detected level of the input audio signal. Package Dimensions unit: mm 4086A-SIP22 [STK412-170] 78.0 70.0 9.0 Features • Pin compatible IC series that covers power ratings from 50 W × 2 channels to 180 W × 2 channels at 0.7 or 0.8% THD, 20 Hz to 20 kHz. This allows the use of a common PCB for all output classes. • The pin arrangement is also unified with that of the three-c [ ... ]

STK412-170 PDF Datasheet Download