This part is a kind of semiconductor called BSP319.

Function of this product has SIPMOS Small-Signal Transistor.

Manufacturers : Infineon Technologies AG

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 VDS 50 V ID 3.8 A RDS(on) 0.07 Ω Package Marking BSP 319 Type BSP 319 SOT-223 BSP 319 Ordering Code Q67000-S273 Tape and Reel Information E6327 Maximum Ratings Parameter Symbol Values Unit Continuous drain current TA = 29 ˚C ID A 3.8 DC drain current, pulsed TA = 25 ˚C IDpuls 15 EAS Avalanche energy, single pulse ID = 3.8 A, VDD = 25 V, RGS = 25 Ω L = 6.2 mH, Tj = 25 ˚C mJ 90 VGS Gate source voltage ESD Sensitivity (HBM) as per MIL-STD 883 Power dissipation TA = 25 ˚C ± 20 Class 1 V Ptot W 1.8 Data Sheet 1 05.99 BSP 319 Maximum Ratings Parameter Symbol Values Unit Chip or op [ ... ]

BSP319 PDF Datasheet Download