Alright, continuing with the debugging of my new board tonight I found another issue worse than the one before: My switching MOSFET is getting so hot that I'm getting molten solder.
I replaced the MOSFET with a short circuit just to see if the components sorounding the MOS were the cause of the problem (mostly a big Inductor I have right next to it) but the copper reaches a temperature of 110°F, not enough to melt solder.
This is my schematic:
As you can see, my VGS is around -11V and I'm running 3A through it using an Electronic Load. Based on the datasheet of my NTD20P06L-D this thing can do up to 15.5A.
Any ideas of what might be going on?
The only thing I could think of was that the heat on the copper could be increasing RDS(on) but at that particular low current it shouldn't be so serious.
I am using the TO-252-3, DPak (2 Leads + Tab) package.