This part is a kind of semiconductor called STK4050V.

Function of this product has AF Power Amplifier (Split Power Supply) (200 W min / THD = 0.08%).

Manufacturers : Sanyo

Image and pinout :

Some of the text within the PDF file :

Ordering number : EN4592A Thick Film Hybrid IC STK4050V AF Power Amplifier (Split Power Supply) (200 W min, THD = 0.08%) Features • Compact packaging supports slimmer set designs • Series designed from 20 up to 100 W (200 W) and pincompatibility (120 to 200 W have 18 pins) • Simpler heat sink design facilitates thermal design of slim stereo sets • Current mirror circuit application reduce distortion to 0.08 % • Supports addition of electronic circuits for thermal shutdown and load-short protection circuit as well as pop noise muting which occurs when the power supply switch is turned on and off. Package Dimensions unit: mm 4051A [STK4050V] Specifications Maximum Ratings at Ta = 25°C Parameter Maximum supply voltage Thermal resistance Junction temperature Operating substrate [ ... ]

STK4050V PDF Datasheet Download