This part is a kind of semiconductor called B0540W.

Function of this product has 0.5A SURFACE MOUNT SCHOTTKY BARRIER RECTIFIER.

Manufacturers : Diodes Incorporated

Image and pinout :

Some of the text within the PDF file :

B0540W 0.5A SURFACE MOUNT SCHOTTKY BARRIER RECTIFIER Features • Low Forward Voltage Drop • Guard Ring Construction for Transient Protection • High Conductance • Lead, Halogen and Antimony Free, RoHS Compliant (Note 1) • "Green" Device (Note 5) • Qualified to AEC-Q101 Standards for High Reliability Mechanical Data • Case: SOD-123 • Case Material: Molded Plastic, “Green” Molding Compound (Note 5). UL Flammability Classification Rating 94V-0 • Moisture Sensitivity: Level 1 per J-STD-020D • Lead Free Plating (Matte Tin Finish annealed over Alloy 42 leadframe) Solderable per MIL-STD-202, Method 208 • Polarity: Cathode Band • Marking Information: See Page 3 • Ordering Information: See Page 3 • Weight: 0.01 grams (approximate) Top View Maximum Ratings @TA = 25 [ ... ]

B0540W PDF Datasheet Download