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Usb Spike Issues

Dhanush Nair
Expert 1360 points
Other Parts Discussed in Thread: TPD2E001

Hi ,

I have been using Stellaris Lm3s5951 ic for my applications. but now i wish to migrate to TIVA. While using stellaris while i connect a keyboard to the USB port  ,the system works fine until any external spikes come via USB.

In presence of an external unwanted EMF spikes the system behaves abnormally .Sometimes  the system hangs and needs to be reset .Is there any solution for this problem ????

Does TIVA take care of such situations???

Regards,
Dhanush

  • 0
    TI__Intellectual 1380 points

    Dhanush,

    Tiva devices can operate successfully in a broad range of environments given the proper system level implementation.

     

    More information is required to help solve your specific problem.  What level of EMI noise is introduced?  Do you have any system level protection such as TPD4S012?  Are you using a shielded cable?  Does your board have a chassis ground isolated from digital ground?

     

    I checked the errata for LM3S5951 and didn’t see anything specific to USB noise susceptibility.  If there is sufficient EMI on any signal (and no system level protection), the induced current can trigger the on-chip ESD protection circuit.  This is intended to protect the device from damage.  Depending on the severity of the event a power cycle or reset may be required.

     

    Stellaris and Tiva parts have on-chip ESD protection that satisfy the requirements of HBM/CDM device standards, but a system level approach is required for successful operation in the end equipment.  This includes proper implementation of bypass capacitors, ground planes, TVS diodes, common mode chokes, and/or other devices. 

    -Austin

  • 0 in reply to TI Austin
    Expert 1360 points

    HI Austin ,

    Actually I am trying to test the limits of EMI noise protection of the system so that it can even work in much adverse industrial conditions.

    We are using TPD2E001 for system protection but removed for the above reasons.

    The cable is not  shielded for inviting more noise.

    The chasis and digital ground are isolated by 0.01micro F/1KV between them

    Regards,

    DHANUSH

    .