configuring a dc:dc regulator
The datasheet is a bit confusing, in part because they use \$V_{SW}\$ for more than one thing. In this case, we're concerned with the voltage across the N-channel MOSFET switch when it is on. 

If you use 1A for your maximum output current and 600m\$\Omega\$ for Rds(on), then \$V_{SW}\$ is 0.6V, so if you derive VBOOST from the 5V output, then


  5.5V > VBOOST – VSW > 2.5V


is satisfied (VBOOST will typically be 3.8V with a 0.6V switching diode). It's nice and safely towards the center of the range. Even if the output voltage was towards the high side of the tolerance range and Vsw and the diode drop were low you'd never exceed 5.5V, so it's safe on the high side as well. 

Note: Do not use the 300m\$\Omega\$ value for Rds(on) because that is "typical" (some units will be worse) and just as important (or more important), it's measured at Tj = 25°C, and you want to use the maximum value, which will be much higher when the chip is hot (which it will be at 1A output).