Datasheet for the ISL88739, a part number from the Intersil product line; the name alone does not describe its function, so consult the document itself for the block diagram and pinout. Datasheets like this give pin functions, typical application circuits, electrical limits and package drawings, which help when checking whether a chip is receiving correct inputs or has failed. Use it alongside the board schematic to measure pins against expected voltages and to confirm package markings before replacing the part.
The button opens the matching file on RM Schematics, or a source page if it is not catalogued there yet. The original attachment is from @ic_mosfet_pdf_datasheets. Enginerys does not host this file.
How to open a .pdf file
The standard format for schematics, block diagrams, power-sequence charts and service manuals.