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Original question:

SN65HVD3085E: How to get the previous version of DS (Revision L)

SN65HVD3085E: Thermal information change between Datasheet Rev.L and M

Go
Genius 4220 points
Part Number: SN65HVD3085E

Hi,

I got PCN letter about data sheet change for SN65HVD3085E due to the addition of new fab site and assembly site.

Is the understanding correct that the new thermal information on D/S rev.M are remeasured value and these value can be applied to all SN65HVD3085E?

Go

  • 0
    TI__Guru 52172 points

    Hi Go,

    Only the new material that is produced will have the updated thermal parameters - if you receive older material (from a distributor or if we have older material left in stock) it will retain the thermal parameters of the old material.

    Best,

    Parker Dodson

  • 0 in reply to Parker Dodson
    Genius 4220 points

    Hi, Parker

    Thanks you for your help.

    Let me ask you about the thermal information change between D/S rev L and M in a little more detail.

    Comparing them, RΘJA and RΘJC(top) got lower on revM, and RΘJB got higher.

    RθJB is defined as the junction to the PCB thermal resistance, and PCB will normally be the main path of the device heat dissipation.

    If RΘJB got higher, I think it means that the heat dissipation capability of the device got worse.
    On the flip side, RΘJA got lower. I think it shows that the thermal performance become better.

    It would be very appreciated if you let me know the reason above.

    Thanks,

    Go

  • 0 in reply to Go
    TI__Guru 52172 points

    Hi Go,

    The part has been redesigned and the new die is made with a different process. The different process has resulted in thermal changes - generally speaking the trend is usually marginally worse on thermal performance due to the new physical properties of the new variant of the die in this device. 

    For the specific specifications mentioned - they are measuring thermal performance in different scenarios. The new die has a higher thermal impedance between the board and the bottom of the pins/IC package. This means the board temperature is going impact the junction temperature more than the previous device. But the other specs are showing the relation between ambient / case and junction temperature - so they are looking at different, but related specs. So the board temperature is of greater importance on the new device -but case and ambient considerations aren't as important in the past. 

    I will say in the vast majority of applications, I am personally not aware of any,  these changes haven't negatively impacted customers - as the changes generally would only make a difference if the part is being ran at max conditions - and even then it may not be an issue depending on the physical layout of the system. One thing to know is that these values fluctuate greatly based on the system parameters - we do have a really good general explainer note on these that you can find here: https://www.ti.com/lit/an/spra953c/spra953c.pdf?ts=1682001573783 as it goes into detail on these specifications and how they apply to the system.

    Best,

    Parker Dodson

  • 0 in reply to Parker Dodson
    Genius 4220 points

    Hi, Parker

    Thank you for your comment.

    Through the redesign and process change, did you also do die-shrink?

    Thanks,

    Go

  • 0 in reply to Go
    TI__Guru 52172 points

    Hi Go,

    The only information I can really say is what was issued in the PCN - the fab/process changed which didn't really impact electrical specifications, but due to the different updated more efficient process  which resulted in slightly different physical characteristics of the die the thermal parameters changed. 

    Best,

    Parker Dodson 

  • 0 in reply to Parker Dodson
    Genius 4220 points

    Hi, Parker

    Thank you for your comment.

    I get the point.

    Thanks,

    Go

  • 0 in reply to Go
    Genius 4220 points

    Hi, Parker

    I have a favor to ask of you.

    Do you have any actual data of  measurement temperature at junction or surface between before and after the change?

    Thanks,

    Go

  • +1 in reply to Go
    TI__Guru 52172 points

    Hi Go,

    These specifications are based on thermal models of the IC which are based on the physical properties of the die/package - since these specifications are going to vary significantly system to system (as mentioned in the application report in an earlier reply) we don't have direct data to share on these specifications.

    Best,

    Parker Dodson 

  • 0 in reply to Parker Dodson
    Genius 4220 points

    Hi, Parker

    Thank you for your advice.

    Does it mean that thermal parameters described on D/S are specified base on the simulation result with thermal models, not based on actual measurement data, right? 

    Thanks,

    Go

  • 0 in reply to Go
    TI__Guru 52172 points

    Hi Go,

    From my best understanding - yes that is correct; we generate thermal data from thermal models and it isn't something that is measured directly. This is mainly due to the variation in systems - so having a base thermal model ends up being a little more helpful since it is not including our testing environment in the specifications (which has a lot of influence on the effective thermal impedance values). 

    Best,

    Parker Dodson