This part is a kind of semiconductor called BSP319.

Function of this product has SIPMOS Small-Signal Transistor (N channel Enhancement mode Logic Level Avalanche rated).

Manufacturers : Siemens Semiconductor Group

Image and pinout :

Some of the text within the PDF file :

BSP 319 SIPMOS ® Small-Signal Transistor • N channel • Enhancement mode • Logic Level • Avalanche rated • VGS(th) = 1.2 ...2.0 V Pin 1 G Pin 2 D Pin 3 S Pin 4 D Type BSP 319 Type BSP 319 VDS 50 V ID 3.8 A RDS(on) 0.07 Ω Package SOT-223 Marking BSP 319 Ordering Code Q67000-S273 Tape and Reel Information E6327 Maximum Ratings Parameter Continuous drain current Symbol Values 3.8 Unit A ID IDpuls 15 TA = 29 °C DC drain current, pulsed TA = 25 °C Avalanche energy, single pulse EAS 90 mJ ID = 3.8 A, VDD = 25 V, RGS = 25 Ω L = 6.2 mH, Tj = 25 °C Gate source voltage Gate-source peak voltage,aperiodic Power dissipation VGS Vgs Ptot ± 14 ± 20 V W TA = 25 °C 1.8 Semiconductor Group 1 Sep-12-1996 BSP 319 Maximum Ratings Parameter Chip or operating tempera [ ... ]

BSP319 PDF Datasheet Download