The smallish SOT-223 v.regs are only good for about 0.3-0.5W dissipation.
Alternatively we can use Rj from the same graph, to can calculate maximum power dissipation at room temperature:Pdmax = (Tjmax - Ta) / Rja = (175C - 25C) / 100 = 1.5WImax = Pdmax / Vdrop = 1.5W / (12V-5V) = 214mAPersonally I have been able to draw up 250mA through the regulator before it started shutting down, which matches the above math.
Do you know how hot 175 degC is?
Instead of using guesses about what the part can do, we should always look to the datasheet to see what the parts can really do. ....