S912ZVML31F1MKF_Problem_VBSx_Pin_Protect

[danny_li]

   1.VBSx Pin of  "S912ZVML31F1MKF" ,  TVS diodes have been added to the pins, The pin is occasionlly damaged，very small probability;

   2.There were other projects before, did the same happen?Can you give me some Suggestions which directions to check?

   3.If I add TVS, do I still need to use Cfilt and Rfilt?

[danielmartynek]

Hello danny.li@weikeng.com.cn,

AC component of voltage peaks on HSx pin can pass through the CBS capacitor to VBSx pin that is internally connected to VCP. The voltage can exceed the maximum ratings and damage the MCU.
Regardless of the TVS diodes, the ringing should be identified using an oscilloscope with proper rating (200 MHz or higher) and differential probes with minimized/compensated loops shall be used.
The optional VBS RC filter can be used to filter the ringing.
I have sent you a presentation that describes the filters.

BR, Daniel