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SN74LVC1T45-Q1: About θja of SN74LVC1T45-EP and SN74LVC1T45-Q1

Noritomo Harukawa
Intellectual 990 points
Part Number: SN74LVC1T45-Q1
Other Parts Discussed in Thread: SN74LVC1T45-EP,

Customers are considering SN74LVC1T45-EP in automotive applications.
The operating temperature range is from -40°C to 125°C.

There is SN74LVC1T45-Q1 as a similar product.
SN74LVC1T45-Q1 is lower cost.
Therefore, I would like to recommend SN74LVC1T45-Q1.

When comparing the data sheet of SN74LVC1T45-EP and SN74LVC1T45-Q1, θja is different.
　SN74LVC1T45-EP : 259 ℃/W (max)
　SN74LVC1T45-Q1 : 286.8 ℃/W (max)

*SN74LVC1T45-EP

*SN74LVC1T45-Q1

Q1.
What is the reason why θja is different?

For example,
Do SN74LVC1T45-EP and SN74LVC1T45-Q1 differ in die attach materials and mold compound materials?


[Background of the question]
In order to have considered SN74LVC1T45-Q1 it is necessary to pass the customer's certification exam.
In order to pass, it is necessary to explain why θja changes with SN74LVC1T45-EP and SN74LVC1T45-Q1.
Could you give me a hand.

-Harukawa

  • 0
    TI__Mastermind 24485 points

    Hello Harukawa-san,

    Yes, the -EP part is specifically designed for high reliability applications, whereas the -Q1 is designed specifcally for automotive applications, including qualification to the Q100 standard.

    These parts are not the same, and therefore likely have differences in materials used based on the intended application environment.

    The biggest difference in θja is likely due to a difference in die size or lead frame size which affects the amount of metal/contact that the device makes in order to be able to dissipate heat.

    Best,
    Michael

  • 0 in reply to Michael J Schultis
    Intellectual 990 points

    Thank you for your reply.

    > The biggest difference in θja is likely due to a difference in die size or lead frame size which affects the amount of metal/contact that the device makes in order to be able to dissipate heat.

    Q.
    Die size and lead frame information are not described in the SN74LVC1T45-EP or SN74LVC1T45-Q1 data sheet.
    Is it possible to obtain these information?

    -Harukawa

  • 0 in reply to Noritomo Harukawa
    TI__Mastermind 24485 points

    Hello Harukawa-san,

    We cannot provide this information as it is TI confidential.

    Ultimately, the change in the ThetaJA is not really going to cause a change in how the device is used. This device consumes/drives very little power and therefore the increase in junction temperature will generally be limited to less than 5°C

    Best,
    Michael