Content originally posted in LPCWare by wmues on Mon Mar 11 03:17:02 MST 2013
I would use the 1117 with an output current of 500mA or less. If you need more output current, the 1117 will get too hot. For 1.5A, you will need a DC DC converter. Try TI TPS62063 or equivalent.
If you have no Pulldown on VBUS, this pin will be floating and your software might be fooled to detect that the device is plugged over USB.