This part is a kind of semiconductor called SF10A400HDS.

Function of this product has Ultra Fast Recovery Diode.

Manufacturers : AUK

Image and pinout :

Some of the text within the PDF file :

SF10A400HDS Ultra Fast Recovery Diode Applications • High speed switching and rectification • Switching mode power supply Features • Ultra-fast reverse recovery time: trr=30ns Max. • Low forward voltage & low reverse current • Low switching loss Ordering Information Type No. Marking Package Code SF10A400HDS SF10A400HDS D2-PAK PIN Connection 132 4 1 2 3,4 1, 2. Anode 3, 4. Cathode D2-PAK Absolute Maximum Ratings Characteristic Repetitive peak reverse voltage Average rectified output current Peak forward surge current (Non-repetitive 60Hz sine wave) Junction temperature Storage temperature range Symbol VRRM IO IFSM TJ Tstg Rating 400 10 120 150 -45 ~ 150 [Tc=25°C] Unit V A A °C °C Electrical Characteristics Characteristic Symbol Forward voltage VF1) Reverse [ ... ]

SF10A400HDS PDF Datasheet Download