LDO 3.3V Overheats on DC input and no load
Like @peufeu states, it is not clear what voltage regulator you really were planning to use, but if we should go by the schematics, it is the LM3480, and that is what the layout is suggesting (as far as I can see from the potato vision image attached) I can tell you right away, that if you as you state in the question -
 were trying to mount a XC6206 on the footprint for U4 from your picture, it will of course not work as expected. Have you even read the datasheets for the parts you use? The physical pinouts are literally on the first pages of the datasheets.

This is essentially what you have connected:







simulate this circuit &ndash; Schematic created using CircuitLab

This is the block diagram for the XC6206 (Taken from the Datasheet:


I don't think I will have to tell you why this is heating up, do I?