This part is a kind of semiconductor called AO4484.
Function of this product has N-Channel Enhancement Mode Field Effect Transistor.
Manufacturers : Alpha & Omega Semiconductors
Image and pinout :

Some of the text within the PDF file :
AO4484 N-Channel Enhancement Mode Field Effect Transistor General Description The AO4484/L uses advanced trench technology to provide excellent RDS(ON) with low gate charge. This is an all purpose device that is suitable for use in a wide range of power conversion applications. AO4484 and AO4484L are electrically identical. -RoHS Compliant -AO4484L is Halogen Free Features VDS (V) = 40V ID = 10A RDS(ON) < 10mΩ RDS(ON) < 12mΩ (VGS = 10V) (VGS = 10V) (VGS = 4.5V) D S S S G D D D D S G SOIC-8 Absolute Maximum Ratings TJ=25°C unless otherwise noted Symbol 10 Sec Steady State Parameter VDS Drain-Source Voltage 40 VGS ±20 Gate-Source Voltage Continuous Drain Current A Pulsed Drain Current Avalanche Current G Repetitive avalanche energy L=0.3mH Power Dissipation A G [ ... ]
AO4484 PDF Datasheet Download
