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SN65HVD235: ESD standard is being used on the datasheet

Enrique Valdez
Prodigy 90 points
Part Number: SN65HVD235
Other Parts Discussed in Thread: STRIKE

Hi All:

For the CAN transceiver what is the ESD testing profile and what method was used like resistance/capacitance for testing the device.

On a previous version of the datasheet it stated that it was capable of sustaining 16kV HBM but the new version indicates 12kV HBM and only 1kV CDM.

We are researching this since we had two failure at the test house at 4kV but we past 2kV.

Thanks

Enrique Valdez

  • 0
    TI__Guru 62920 points
    Hi Enrique,

    Which datasheet are you referencing? I am looking at the version on the web (www.ti.com/.../sn65hvd235.pdf) and it specifies 16 kV on CANH and CANL using the JEDEC JS-001 HBM model. (The CDM level is still 1 kV.)

    What type of ESD testing resulted in the 4-kV failure? Was it IEC 61000-4-2 or ISO 10605? Which pins did you strike, and what was the failure mechanism?

    Regards,
    Max
  • 0 in reply to Miguel Robertson
    Prodigy 90 points
    Hi Max:

    The CAN module stills performed, but its heating up.

    The pins that were ESD are CAN-H and CAN-L.

    Also correcting my previous statement this module was tested at 4KV and passes with no issues but after the 2 units were tested at 6KV they failed for Higher current consumption. we now know that the CAN module still works but is heating up consuming more current.

    Thanks
    Enrique
  • 0 in reply to Enrique Valdez
    TI__Guru 62920 points
    Enrique,

    It's possible for ESD strikes on the CAN lines to cause a latch-up state where the transceiver sinks larger currents (but remains otherwise functional). For devices that specify powered ESD (per specs like ISO 10605 or IEC 61000-4-2), this sort of failure mode should not occur within the spec range. The HVD23x seems to only be specified for handling ESD (i.e., HBM), though, and so if you are testing using a different standard or methodology then the device may not be immune. In that case, I'd recommend adding a transient voltage suppression (TVS) diode to clamp the voltages at the CAN bus to within the component's absolute maximum voltage ranges. Another option (if you had a 5-V rail available) would be to use a transceiver with higher ESD immunity like TCAN1042V (which has a separate IO voltage supply which would allow interfacing to a 3.3-V controller).

    Regards,
    Max
  • 0 in reply to Miguel Robertson
    Prodigy 90 points
    Hi Max:

    The Lab used the following standard

    Immunity to Electrostatic Discharge, Packaging and
    Handling Sensitivity Classification, Non-Powered Mode
    SAE J1113-13 Compliant (see 9.4.1)

    Thanks
    Enrique
  • 0 in reply to Enrique Valdez
    TI__Guru 62920 points
    Enrique,

    Thanks for the additional information. SAE J1113-13 uses a discharge model with C = 150 pF and R = 2000 Ohms for packaging/handling testing. The HBM model is similar, using 100 pF and 1500 Ohms. It is strange to see such a large difference in performance, then.

    Are the failing units permanently damaged, or do they return to normal current consumption after a power cycle?

    Is it possible to determine which pins were stressed and which are now damaged?

    Regards,
    Max
  • 0 in reply to Miguel Robertson
    Prodigy 90 points

    Hi Max:

    The units are permanently damaged but they do not return to the normal current consumption after power cycle, the Pins are 6 and 7 CAN high and CAN low as previously stated.

    Thanks

    Enrique

  • 0 in reply to Enrique Valdez
    TI__Guru 62920 points
    Enrique,

    Sorry for the delay - I was out of the office on vacation last week. I'm assuming the system was powered on during the strike - is that correct? If so, sometimes devices can be more susceptible to ESD strikes while in the powered state (which would not be encompassed by the HBM specification). It may just be that the HVD235 is particularly sensitive to this particular test (SAE J1113-13). In that case using a TVS for protection is most likely the simplest solution. Using another more robust transceiver may be another option.

    The reason I asked about which pins were damaged is that sometimes it is possible to have transient strikes on some pins cause secondary failures elsewhere. For example, the CANH/CANL pins may be able to withstand a particular transient by shunting the transient currents to ground (through internal ESD protection clamps), but the corresponding ground noise may damage an MCU or cause a voltage regulator to lose its output regulation momentarily and stress the VCC rail, etc. In those cases, performance can be improved by adding protection elsewhere (e.g., by increasing decoupling capacitances, etc.). I think this is a less likely scenario, but wanted to mention it in case further debug is found to be needed.

    Max