USB pins PA11, PA12 failing short during hot plugin of type C port on board(STM32H56V3G)

[Roy_B1027]

Hi ST Team,

In our design, the USB pin pairs from PA11, PA12 our failing short multiple times during hot plug in of type C port to power the board. The USB pin pairs does not directly go to type C port rather it goes through this chip PCMF3USB3S (ESD + EMI filter) from Nexperia. Currently we do not have any ESD protection on VBUS pin. The VBUS +5V currently generates 3.3VDD to power the STM32H56V3G on our board. There is also a diode as connected reverse b/w VBUS +5V and 3.3Vdd output as recommended in AN4899.

Can you please give us some insights on why this could be happening and what would be the possible solution

 

 

[Bowman32]

Refer to AN5225 "Introduction to USB Type-C® Power Delivery for STM32 MCUs and MPUs" for recommendations on USB Type-C protection, including ESD/EOS protection of VBUS.

[TDK]

USB pin pairs from PA11, PA12 our failing short multiple times during hot plug

What are PA11 and PA12 being shorted to? How did you determine that?