This part is a kind of semiconductor called STA481A.

Function of this product has NPN Darlington With built-in avalanche diode.

Manufacturers : Sanken

Image and pinout :

Some of the text within the PDF file :

STA481A Absolute maximum ratings Symbol VCBO VCEO VEBO IC ICP IB PT Tj Tstg Ratings 60±10 60±10 6 1 2.5 (PW≤1ms, Du≤25%) 0.5 4 (Ta=25°C) 16 (Tc=25°C) 150 –40 to +150 NPN Darlington With built-in avalanche diode (Ta=25°C) External dimensions D ••• STA400 (Ta=25°C) Electrical characteristics Symbol ICBO IEBO VCEO hFE VCE(sat) VBE(sat) VFEC ton tstg tf fT Cob 50 2000 60 5000 1.0 1.6 1.4 0.5 2.5 1.0 50 14 Specification min typ max 10 3 70 10000 1.5 2.2 1.8 V V V Unit Unit V V V A A A W °C °C Conditions VCB=50V VEB=6V IC=1mA VCE=4V, IC=0.5A IC=0.5A, IB=1mA IFEC=0.5A VCC 30V, IC=0.5A, IB1=–IB2=1mA VCE=12V, IE=–0.1A VCB=10V, f=1MHz µA mA V µs µs µs MHz pF sEquivalent circuit diagram 3 2 1 R1 R2 5 4 6 7 8 9 10 R1: 6kΩ typ R2: 400Ω typ Characteristic [ ... ]

STA481A PDF Datasheet Download