STM32H725RG VFQFPN68 power scheme. Am I doing it right?

[jmarino]

Can somebody tell me whether I am, or not, powering this STM32H725RG in the right way?

As far as I know, after reading several times the specs, the 68 pin package doesn't have LDO (SMPS only).

I've built my first board this way and the MCU got burnt.

Thanks.

[STTwo-32]

Hello @jmarino 

I'm not a HW expert. But i can recommand you to take a look at the AN5419. It should be really helpful.

Best Regards.

STTwo-32 

[jmarino]

Thank you, but I already did:

https://community.st.com/t5/stm32-mcus-boards-and-hardware/what-s-the-correct-power-supply-scheme-for-h725-735-vfqfpn68/m-p/644714

[MHoll.2]

Ok You say you did check AN5419, so please add the missing capacitors from Table 2. (4x 100nF + 1x 4.7nF on VDD, 1x 220pF on VLXSMPS)

What is connected to VDDA and VBAT?

[jmarino]

4x100nF and 1x4.7uF on VDD are connected too (they don't appear in the part of schematic that I posted at first, but they are):

About the 220pF capacitor, AN5419 says it's not used with VFQFPN68 package, but only with LQFP and BGA:

"LQFP/BGA packages: 220 pF ceramic capacitor on VLXSMPS."

[jmarino]

VBAT is connected to VDD through a double schottky diode, to allow self powering when VDD is present, and powering from a external battery when it's not. It also can be connected directly to a external battery.

[MHoll.2]

OK, I don't see any error on the schematic, I did not check your pinout, but to me there seems to be some VSS pin missing. Where did you connect the Exposed Pad?

[jmarino]

All the VSS pins and exposed pad are connected to GND.

The schematic doesn't show all of VSS pins because Kicad symbols hide them and leave only one.

Thank you for your time.