It is important to note that the output current rating for each of these three devices is dependent on input and output voltage. Referring to the ISL9120IR as an 800 mA device, the ISL91107IR as a 2 A device, and the ISL91127IR as a 3 A device respectively, this chart here illustrates how the max rating varies with input/output conditions. Depending on the input and output voltages, each device may actually have higher or lower current capability. There is a similar chart in the datasheets for the ISL9120IR and ISL91107IR that will need to be referred to in order to verify that the device will meet design needs.