This part is a kind of semiconductor called APM2055NU.

Function of this product has N-Channel Enhancement Mode MOSFET.

Manufacturers : Anpec Electronics

Image and pinout :

Some of the text within the PDF file :

APM2055NU Features · 20V/10A, RDS(ON)=55mW (Typ.) @ VGS=10V RDS(ON)=75mW (Typ.) @ VGS=4.5V RDS(ON)=140mW (Typ.) @ VGS=2.5V · Reliable and Rugged · Lead Free and Green Devices Available (RoHS Compliant) ® N-Channel Enhancement Mode MOSFET Pin Description D S G Top View of TO-252-3 D Applications · Power Management in Desktop Computer or DC/DC Converters G S N-Channel MOSFET Ordering and Marking Information APM2055N Assembly Material Handling Code Temperature Range Package Code Package Code U : TO-252-3 Operating Junction Temperature Range C : -55 to 150 oC Handling Code TR : Tape & Reel (2500ea/reel) Assembly Material G : Halogen and Lead Free Device APM2055N U : AXPXMXX2X055N XXXXX - Lot Code Note : SINOPOWER lead-free products contain molding compounds/die attach materials [ ... ]

APM2055NU PDF Datasheet Download