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TPS22968-Q1: Does TPS22968 has SOA information?

Jiang Boqian
Intellectual 655 points
Part Number: TPS22968-Q1
Other Parts Discussed in Thread: TPS22968, TPS22966, TPS25940-Q1, TPS22966-Q1,

Dear expert,

Happy new year!

I see two similar laod switch TPS22966 and TPS22968, I first choose 66 for lower Rdson. However, I noticed that although both switchs are rated for 4A continues current, 66 has a SOA curve, indicating that for Tamb 85C and 100% on time, the continues current derates to about 1A. My question is, does this also applys to TPS22968? If I want 100% on time, 4A continues current under 85C, which is quite normal for automotive use case, which part can I choose, maybe eFuse like TPS25940-Q1?

Thank you.

  • 0
    TI__Genius 10855 points

    Hi Jiang, 

    Thanks for reaching out on E2E and being patient as many of us are returning from holidays! Happy Holidays!

    The TPS22966-Q1 is an older device, we don't generate SOA curves for other load switches including the TPS22968-Q1.

    The SOA curve, and ultimately the current carrying capability of the device is dependent on the junction temperature and self-heating of the device. Taking a look at the TPS22968-Q1, we can calculate the self-heating and thermal junction (Tj) temperature using the following equations:

        Iout= 4A
        Ron=~37mohm, Figures 7-8
        Tj max= 150C
        θj-a=55.6 C/W *on their board

        delta Tj = Iout^2 * Ron * θj-a
                      = 4^2 * 0.037 * 55.6
                      = 32.95C
        Tj = delta Tj + Ta max
            = 85 + 33C
            = 118C

    Since the device will heat up to ~118C during operation at 4A, the device will continue to operate normally at 85C ambient. I don't see any issues running the TPS22968-Q1 at 85C. 

    The SOA curves for the TPS22966-Q1 look incorrect, I will check with design to make sure the graph accurately represents the current deration.

    Thanks,

    Arthur Huang

    To find the latest information on Power Switches, visit www.ti.com/powerswitch