This part is a kind of semiconductor called STK4122II.

Function of this product has AF Power Amplifier.

Manufacturers : Sanyo

Image and pinout :

Some of the text within the PDF file :

Ordering number: EN2203B Thick Film Hybrid IC STK4122II AF Power Amplifier (Split Power Supply) (15W + 15W min, THD = 0.4%) Features • The STK4102II series (STK4122II) and STK4101V series (high-grade type) are pin-compatible in the output range of 6W to 50W and enable easy designing. • Small-sized package whose pin assignment is the same as that of the STK4101II series • Built-in muting circuit to cut off various kinds of pop noise • Greatly reduced heat sink due to substrate temperature 125°C guaranteed • Excellent cost performance Package Dimensions unit: mm 4083 [STK4122II] Specifications Maximum Ratings at Ta = 25°C Parameter Maximum supply voltage Thermal resistance Junction Temperature Operating substrate temperature Storage temperature Available time for load shor [ ... ]

STK4122II PDF Datasheet Download