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TMS320F280045: RESET PIN short to GND when EMC RI test

Jon WANG
Intellectual 960 points

Part Number: TMS320F280045

During the EMC RI testing, the radiation probe  was located about 1cm above TMS320F280045PZS under testing conditions (-1200V, 1000ns). The reset pin of TMS320F280045PZS was short  to GND and damaged. This phenomenon can be reproduced.Could you pls help review this issue? Thanks.

DRV500_MCU.pdf

  • 0
    TI__Guru* 95315 points

    Jon,

                Based on the part# in the schematic for U26 (S-80928CNMC), it appears the open-drain version of this device is used, which is correct. In this case, R123 is unnecessary and will create a voltage divider. Under this scheme, the -XRS pin may not be at the correct levels for the active and inactive states. Please verify this with an oscilloscope. Now, I am not saying this is the root-cause for the vulnerability you see in the -XRS pin, but this is something you should definitely look into. And double-check  you are not using the CMOS output version of this device.

    I have seen different types of soft upsets (device getting reset, device “hangs”, registers/bits getting corrupted) in radiated immunity tests, but I have not experienced a pin getting damaged in RI tests. What happens if you reduce the magnitude of the noise voltage? Do you only see a soft error? Is there a threshold voltage above which the pin gets damaged?

  • +1 in reply to Hareesh Janakiraman
    TI__Guru* 95315 points

    Jon,

       Are there any updates you can share about this issue?