This part is a kind of semiconductor called SF36.

Function of this product has 3.0 Amp Super Fast Rectifier 50 to 600 Volts.

Manufacturers : Micro Commercial Components

Image and pinout :

Some of the text within the PDF file :

MCC Features High Surge Capability Low Forward Voltage Drop High Current Capability High Reliability
  omponents 21201 Itasca Street Chatsworth    !"# $ %    !"# SF31 THRU SF38 3.0 Amp Super Fast Rectifier 50 to 600 Volts DO-201AD • • • • • • • Maximum Ratings Operating Temperature: -55°C to +125 °C Storage Temperature: -55°C to +150 °C For capacitive load, derate current by 20% Maximum Recurrent Peak Reverse Voltage 50V 100V 150V 200V 300V 400V 600V Maximum RMS Voltage 35V 70V 105V 140V 210V 280V 420V Maximum DC Blocking Voltage MCC Part Number SF31 SF32 SF33 SF34 SF35 SF36 SF38 D 50V 100V 150V 200V 300V 400V 600V A Cathode Mark B D Electrical Characteristics @ 25° C Unless Otherwise Specified Average Forw [ ... ]

SF36 PDF Datasheet Download