This part is a kind of semiconductor called FDZ1905PZ.
Function of this product has Common Drain P-Channel 1.5V PowerTrench WL-CSP MOSFET.
Manufacturers : Fairchild Semiconductor
Image and pinout :
Some of the text within the PDF file :
FDZ1905PZ Common Drain P-Channel 1.5V PowerTrench® WL-CSP MOSFET July 2008 FDZ1905PZ Common Drain P-Channel 1.5V –20V, –3A, 123mΩ Features Max rS1S2(on) = 126mΩ at VGS = –4.5V, IS1S2 = –1A Max rS1S2(on) = 141mΩ at VGS = –2.5V, IS1S2 = –1A Max rS1S2(on) = 198mΩ at VGS = –1.8V, IS1S2 = –1A Max rS1S2(on) = 303mΩ at VGS = –1.5V, IS1S2 = –1A Occupies only 1.5 mm2 of PCB area, less than 50% of the area of 2 x 2 BGA Ultra-thin package: less than 0.65 mm height when mounted to PCB High power and current handling capability HBM ESD protection level > 4kV (Note 3) RoHS Compliant tm PowerTrench® WL-CSP General Description MOSFET This device is designed specifically as a single package solution for the battery charge [ ... ]