This part is a kind of semiconductor called 2SA2057.

Function of this product has Silicon PNP epitaxial planar type.

Manufacturers : Panasonic Semiconductor

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Some of the text within the PDF file :

Power Transistors 2SA2057 Silicon PNP epitaxial planar type Unit: mm Power supply for audio & visual equipments such as TVs and VCRs Industrial equipments such as DC-DC converters ■ Features • High speed switching (tstg: storage time/tf: fall time is short) • Low collector-emitter saturation voltage VCE(sat) • Superior forward current transfer ratio hFE linearity • TO-220D built-in: Excellent package with withstand voltage 5 kV guaranteed 15.0±0.5 9.9±0.3 4.6±0.2 2.9±0.2 φ 3.2±0.1 13.7±0.2 4.2±0.2 Solder Dip 1.4±0.2 1.6±0.2 0.8±0.1 3.0±0.5 2.6±0.1 0.55±0.15 ■ Absolute Maximum Ratings TC = 25°C Parameter Collector-base voltage (Emitter open) Collector-emitter voltage (Base open) Emitter-base voltage (Collector open) Collector current Peak collector curr [ ... ]

2SA2057 PDF Datasheet Download