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DRV8329-Q1: High temperature operation

Oscar Liborio
Intellectual 930 points
Part Number: DRV8329-Q1

Tool/software:

Hello,

My costumer is using the device in a pump which is required to operate in normal operation mode (full rpm range) up to a board temperature of 140°C (maximum ambient temperature <100 C).

In the region from 140°C up to 150°C a derating is allowed and above 150°C the pump is allowed to stop operation.

Based on the operating condition, the junction temperature is 150 C so the device should be able to fully operate in the temperature range mentioned above. Correct?

considering a T- ambient of 100 is it possible to exceed the T - junction of 150 C due to self heating ?

Thanks

  • 0
    TI__Mastermind 23406 points

    Hey Oscar,

    Thank you for the question. Let me review this and aim to provide feedback by Thursday.

    Best,

    Akshay

  • 0 in reply to Akshay Rajeev Menon
    TI__Mastermind 23406 points

    Hey Oscar,

    In DRV8329-Q1 the recommended ambient temperature is up to 125C and the junction can reach 150C till when the device can operate. 

    It is a bit hard to comment if the junction will exceed 150C at ambient temp of 100C as this will have a lot of dependency on PCB design. If there is not sufficient thermal dissipation paths in the layout and the exposed pad is not properly grounded then it is possible to exceed the junction temp limit. But ultimately it is hard to tell from system to system.

    Is the customer running into heating issues?

     Best,
    Akshay

  • 0 in reply to Akshay Rajeev Menon
    TI__Intellectual 930 points

    Hi Akshay,

    Do we have data of the device running at full load at 100 C (or similar) ambient temperature?

    Thanks,

    Oscar

  • 0 in reply to Oscar Liborio
    TI__Mastermind 23406 points

    Hey Oscar,

    Let me check internally.

    Best,

    Akshay

  • 0 in reply to Akshay Rajeev Menon
    TI__Intellectual 930 points

    Hi,

    Maybe the question would be what is the max power dissipation / temperature increase that we should expect?

    Or can you assure that under any operating condition the device won´t go above 150 C for T amb at 100 C?

    Also right now they are having issue with our MCU since due to limited Abs Max (125 C)

    I see that we have a part with integrated commutation on the roadmap (MCF, MCT). Would this have the same temp spec as the DRV part? 

    Thank you!

    Oscar

  • 0 in reply to Oscar Liborio
    TI__Mastermind 23406 points

    Hey Oscar,

    The thermal dissipation would depend strongly on the board design and how much copper is available to dissipate the heat. So it is hard to tell if under specific design and system the junction wont go above 150C.

    Our DS states that as long as your systems meets the ambient max temp and junction max temp then the device will work as intended/spec'd.

    For the MCx parts I suggest looking into the max temp ratings in the DS for junction and ambient.

    I will ask our team to follow-up over email on any MCx roadmap that will be applicable from an automotive standpoint.

    Best,
    Akshay

  • 0 in reply to Akshay Rajeev Menon
    TI__Intellectual 930 points

    Hi Akshay,

    I understand that the power dissipation strongly depends on their layout. but using our EVM and no active cooling (no air fan, or other) what would be  the max power dissipation / temperature increase ?

    From the DS the max operating ambient temperature is 125 while T abs max is 150. If I would be the costumer based on this I would except the max temperature increase to be always <25 C, Otherwise I wouldn´t be able to operate the device at 125 C. Do you agree?

    Bests,

    Oscar

  • 0 in reply to Oscar Liborio
    TI__Mastermind 23406 points

    Hey Oscar,

    I don't believe we have tested the EVM under high ambient temperatures, as the goal from EVm perspective is too evaluate device operation modes by the customer.

    Temp ratings are referring to abs max operating conditions: i.e. if these conditions are met (ambient is less than 125C and junction is less than 150C) then our part was designed to handle it. If either condition is violated (ambient greater than 125C or junction greater than 150C) then we cannot guarantee device performance/reliability.

    You can have device powered on under 125C ambient and not be switching my FETs and the device may generate some temp rise with the quiescent current, but as long as it is below 150C on the die the device should survive.

    If the board temp can get to 140C and our device is on the board, and our device is near the heat source that is getting up to 140C, then the ambient around our device could be above 100C even if the ambient around the larger context of the system as a whole may only be <100C.

    The customer would need to do system level testing on their board to analyze the power dissipation under their exact operating conditions (dependent on average gate current, loading on external regulators, etc.) to see if the thermal ratings are met.

    Best,

    Akshay