This part is a kind of semiconductor called 31DF6.

Function of this product has Super Fast Rectifiers.

Manufacturers : Taiwan Semiconductor

Image and pinout :

Some of the text within the PDF file :

CREAT BY ART 31DF4 - 31DF6 3.0AMPS. Super Fast Rectifiers DO-201AD Features — High efficiency, low VF — High current capability — High reliability — High surge current capability — Low power loss — Green compound with suffix "G" on packing code & prefix "G" on datecode Mechanical Data — Cases: Molded plastic — Epoxy: UL 94V-0 rate flame retardant — Lead: Pure tin plated, lead free, solderable per MIL-STD-202, Method 208 guaranteed — Polarity: Color band denotes cathode end — High temperature soldering guaranteed: 260℃/10 seconds — Weight: 1.2 grams Ordering Information (example) Part No. Package Packing INNER TAPE Packing code 31DF4 DO-201AD 500 / AMMO box 52mm A0 Maximum Ratings and Electrical Characteristics Rating at 25 ℃ ambient temperature unless otherwise sp [ ... ]

31DF6 PDF Datasheet Download