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STM32F429ZIT6 shortcircuit on a Bare PCB

Question asked by de Haro Carbonell on Jun 12, 2017
Latest reply on Nov 17, 2017 by de Haro Carbonell

Dear ST Community,

I am developing an inverter for power management. I started the project using the STM32F429I-DISCO and all tests performed were OK using this board, so we decided to use this STM32F429ZIT6U microcontroller for our design. We designed a PCB using the STM-QFP-144_L footprint from the official library STMicroelectronics STM32 F4.IntLib  (anyway i checked the footprint and looks like correct).

Using the BEEP mode of the multimeter, just the Bare PCB without any component (resistrors, DC-DC, micro, ...) there is not any shortcircuit, but as soon as I solder this microcontroller (using proper tools for that, no shortcircuits done by soldering proces), so just the BARE PCB and micro controller,  suddenly there is a shortcircuit between VDD (+3.3V) and VSS (gnd).

I have checked everything, foortprints, schematic, datasheet,... and i am completly lost.

Regarding the schematic, the microcontroller HARDWARE part, is just a copy from the DISCOVERY, and i have added other components for our project, but please note that the issue i have is just the BARE PCB only with the microcontroller...
I have connected to +3.3V all VDD pins.
I have connecter to GND all VSS pins and VSSA.

VBAT, VDDA, VREF+, PDR_ON, NRST are not connected yet because they are connected to VDD or GND througth resistors and ferrites which are not assembled yet due to this issue.

I am wondering if it has to be connected all capacitors, oscillator and reset and boot components, or if there must be conetion from boot to gnd...
I bought the STM32F429ZIT6, and the DISCOVERY evaluation board is using the STM32F429ZIT6U, but i dont think that there are any differences.

Attached i send a schematic just with the microcontroller part, the rest of the Hardware design are connected to GPIO ports, and because of there are not any componets assembled in my PCB yet, it is not necessary to send that info.
Any comment is appreciated.

Thank you in advance and best regards.