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Original question:

TM4C123GH6PZ: TM4C123GH6PZ - ESD RELATED ISSUES

TM4C123GH6PZ: LATCH-UP AND FREEZING OF MICRO DURING ESD

user489789
Prodigy 220 points
Part Number: TM4C123GH6PZ

Tool/software:

Hi TI

For my earlier query related to ESD,  the answer provided couldn't help in anyway. I have of-course seen the datasheet and the ESD ratings provided. Now that our design has travelled a long way and performance trials are completed, it would be not possible to change the design at this juncture. Alternately, we want to protect the ECU for the ESD events (+/- 6kV contact and +/-8kV discharge) on the product not  directly on the device. So we seek your support in overcoming the latch-up / freezing of the micro during the ESD. Either resetting or latching up is not acceptable as per the standard. We have taken care of all the points in the design such as adding ESD diodes, TVS diodes, multi layer PCB, proper shielding and grounding, minimized cables , shielded cable harness, emi-emc gaskets and everything

Pl do suggest how the MCU can be protected off from freezing. VERY URGENT AND CRUCIAL

thanks

ratnaA

  • 0
    TI__Guru**** 190496 points

    Hi,

      As much as I wanted to provide guidance, you are testing the MCU beyond its ESD rating which is out of spec. You need to add ESD protection around the MCU so any ESD events reaching the MCU does not exceed its specified rating per JEDEC standards for which the device is qualified against. 

    user489789 said:
    We have taken care of all the points in the design such as adding ESD diodes, TVS diodes, multi layer PCB, proper shielding and grounding, minimized cables , shielded cable harness, emi-emc gaskets and everything

    Are you sure these diodes, TVS are rated for your ESD voltages ( (+/- 6kV contact and +/-8kV discharge) ?

    In the meantime, I will check internally any guidance on ISO10605. 

  • 0 in reply to Charles Tsai
    Prodigy 220 points

    Hi 

    The test Standard is ISO13766 Part 1

    PFB the list of ESD components added in our design based on the type of IO / Function

    Request you to get back with solution to mitigate this problem. Very are very badly in need to complete this certification test before 2nd week of April 2025

    thanks in advance

    ratnaA

  • 0 in reply to user489789
    TI__Guru**** 190496 points

    Earlier in the other thread you said ISO10605 and now you say ISO13766. It is very confusing. While I'm reaching out to our internal team for guidance, all I can say at this moment is that if you are testing beyond what the MCU is rated for its ESD rating as specified on the datasheet, there is no guarantee that it will work as far as preventing latchup or hang. 

  • 0 in reply to Charles Tsai
    TI__Guru**** 190496 points

    Talking to our expert, he basically says that ISO 10605 are system level tests at an "ECU level" and if you expose our devices directly to these levels you will potentailly blow up our devices. It is customers responsibility to design protection and not pass such voltages to our devices.  Also note that ESD studies on components are NOT run on power on conditions. If customer is doing such ESD tests and seeing latchup, it is outside of our controls. Lastly, TM4C123 is not an automotive rated device. This below document will be useful to understand more about component and system level ESD testing. 

    Industry Council_System Level ESD_March2012.pdf

    Here is an app note about ISO10605 https://www.ti.com/lit/an/slva954b/slva954b.pdf

  • 0 in reply to Charles Tsai
    Prodigy 220 points

    Hi

    Thanks for your response. Just to clarify, the standard ISO13766 Part 1, takes reference from other ISO standards for all the tests prescribed in it. Like wise for ESD, of course 10605 is being referred to.

    And we are not testing the MCU directly for this severity and its at the ECU level qualification. We have qualified another ECU with same functionality wherein the MCU used is operating at 5V and we have successfully qualified the ECU for spec as per the standard. 

    But we are facing challenge in the designs with 3.3V operated MCU and other chip sets. If any of your experts could suggest any other tips and tricks to mitigate this problem, we would be very grateful

    Pl check is there a out 

    thanks in advance

    ratnaA

  • 0 in reply to user489789
    TI__Guru**** 190496 points

    HI,

      I hope you had a chance to read through the document I provided. I don't know if your rest of components are capable to withstanding the rated test. You will need to go through that yourself. One of the slides talks about the TVS diode that needs to be able to protect and clamp within the MCU's HBM limit.