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TPSM53603: Is their a max dv/dt requirement for the input voltage signal?

Mustafa Homsi
Expert 1171 points
Part Number: TPSM53603

Hello, when we hot-plug a 24V power adapter to the input of this part, it will fail and measure short thereafter. If we connect the same power adapter cold (make the connection then power the adapter), the system works fine. We did scope the power adapter output and we are measuring a clean 24V ramp with no noticeable overshoot. However, the dv/dt of the rampl when it is hot-plugged is much higher than the adapter powerup dv/dt. We think this high dv/dt may be causing a high inrush current internally and damaging the board. Can you please comment? Thank you.

  • 0
    TI__Genius 12365 points

    Hi Mustafa 

    Can you measure how large the dv/dt value is when hot-plug the power adapter? Thank you.

    Best regards.

  • 0
    Expert 1171 points

    I didn't have an extremely high scope resolution but it was higher than 50kV/s.

    Regardless of my test setup measurement value, I am looking to find the part dv/dt handling parameter. What is the max dv/dt input signal we can apply to this part? Thank you.

  • 0 in reply to Mustafa Homsi
    TI__Mastermind 27030 points

    HI Homsi:

    for hot-pluggin as there is parasitic inductor in the line will resonant with input capacitor. so the input voltage at IC will be higher than 24V, it can even higher than TPSM53603 max voltage. 

    Not sure whether you can put more electrolytic capacitance at input side to reduce the overshoot of input. it will be help.

    Thanks

  • 0 in reply to Daniel Li14
    Expert 1171 points

    Hello Daniel,

    If the part is designed to survive hot-plugging but requires either additional input caps and/or additional input series impedance then can you please specify the minimum value required to avoid rinigng. Thank you. 

  • 0 in reply to Mustafa Homsi
    TI__Mastermind 27030 points

    Homis:

    we can't give a min value , because we don't know the parasitic inductance of the wire and dv/dt of input. it is better to add like 100uF electrolytic capacitor and measure the VIN PIN voltage when you do the hot-plugging test. if the ringing not over 32V, leave around 5-6V room to its max voltage in worse case(lowest working temperature), then we think it is safe.