I have a programmable (using a Arduino MEGA) 32x32 RGB LED matrix:
that I want to play with. Power for it is 5VDC and up to 4A, so I am using a 5V LM1085 LDO vreg（pdf） which is supplied by a 19.5V, 6.7A laptop power supply.
The program I am running on it now is only taking 0.5A, but the vreg is getting very hot.
My question is; why is it overheating at 0.5A when it can easily supply 3A? It is attached to a heat sink with heat transfer paste. I have checked all my connections and they are correct and solid.
Here is a schematic of what I have:
It isn't visibly apparent, but there is a 4-way (electrical) junction with: the load, the capacitor, the IC Ground pin, and the negative output of the laptop PS.
Thanks to anyone that can help