I recently ordered some PCB. When I started soldering stuff to it, everything is working fine except the microcontroller.
I tried to solder just the uC alone with decoupling caps besides and power it with 3.3V from power supply - works OK.
But then, when I solder the usb port and 3.3 regulator something weird happens - instead of consuming 0.1A inrush current and then go to sleep with 0A consumption it just goes crazy and consume 1.3A and inevitably fry itself (it is not soldering short on the board because uC gets hot).
LM1117 regulator is working correctly, gives stable 3.3V, the voltage on power pins is 3.3V.
After soldering uC I thoroughly inspected it under a microscope so I am sure there are no sorts (unless they somehow made it under the package).
The layout should be correct, I triple checked the power pins numbers and the layout in itself is quite simple, rat nets don't allow me to connect anything by mistake basically.
I have no idea what is going on and I already fried couple of expensive chips.
Does anyone can give an advice what should I look for?
The weird thing is that uC works well without USB and LM1117 soldered, so it seems that there is a problem there, but I can't find anything wrong about it.
Here are top and bottom views of the PCB. The power goes from USB port on the left, converted to 3.3 with LM1117 and then goes to uC in LQFP144 package (STM32F429ZI). W6 and W1 are just test pads.