This part is a kind of semiconductor called BDX54C.

Function of this product has COMPLEMENTARY SILICON POWER DARLINGTON TRANSISTORS.

Manufacturers : STMicroelectronics

Image and pinout :

Some of the text within the PDF file :

BDX53B - BDX53C BDX54B - BDX54C Complementary power Darlington transistors Features ■ Good hFE linearity ■ High fT frequency ■ Monolithic Darlington configuration with integrated antiparallel collector-emitter diode Application ■ Audio amplifiers ■ Linear and switching industrial equipment Description The devices are manufactured in planar base island technology with monolithic Darlington configuration. 3 2 1 TO-220 Figure 1. Internal schematic diagram Table 1. Device summary Order code BDX53B BDX53C BDX54B BDX54C Marking BDX53B BDX53C BDX54B BDX54C R1 typ.= 10 kΩ R2 typ.= 150 Ω Package TO-220 Packaging Tube October 2007 Rev 4 1/7 www.st.com 7 Electrical ratings 1 Electrical ratings BDX53B - BDX53C - BDX54B - BDX54C Note: Table 2. Absolute maximum ratings Sym [ ... ]

BDX54C PDF Datasheet Download