This part is a kind of semiconductor called 2SJ503.

Function of this product has DC/DC Converter Applications.

Manufacturers : Sanyo Semicon Device

Image and pinout :

Some of the text within the PDF file :

Ordering number:ENN5932 P-Channel Silicon MOSFET 2SJ503 DC/DC Converter Applications Features · Low ON resistance. · Ultrahigh-speed switching. · 4V drive. Package Dimensions unit:mm 2083B [2SJ503] 6.5 5.0 4 1.5 2.3 0.5 0.85 0.7 5.5 7.0 0.8 1.6 1.2 0.6 1 2 3 7.5 0.5 2.3 2.3 1 : Gate 2 : Drain 3 : Source 4 : Drain SANYO : TP unit:mm 2092B [2SJ503] 6.5 5.0 4 2.3 1.5 0.5 5.5 7.0 0.85 1 0.6 0.5 0.8 2 3 2.5 1.2 0 to 0.2 1.2 2.3 2.3 1 : Gate 2 : Drain 3 : Source 4 : Drain SANYO : TP-FA Any and all SANYO products described or contained herein do not have specifications that can handle applications that require extremely high levels of reliability, such as life-support systems, aircraft’s control systems, or other applications whose failure can be reasonably [ ... ]

2SJ503 PDF Datasheet Download