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Voltage applied to VOUT of LT3083

Niels
on Jul 15, 2020

Hello,

what will happen if an external  voltage is applied to VOUT of the LT3083, that is greater than the voltage at the SET pin, but smaller than the voltage at VIN?

What will happen if an external  voltage is applied to VOUT of the LT3083, that is greater than the voltage at the SET pin, and greater than the voltage at VIN?

LTSpice simulation shows that the LT3083 will block any voltages externaly applied to VOUT, no reverse current is flowing from OUT to IN, SET or Vcntrl. Is that true?

Regards, Niels

  • 0 on Jul 21, 2020 8:59 AM 7 months ago

    Dear Analog Support Team,

    nearly a week ago, I asked the question you find above. Until now, I got no answer at all.

    I wonder why.
    Is my question too complicated?
    Maybe my wording is so bad that you do not understand what I am asking for?
    Or is it the support policy of Analog Devices to always let customers wait for several days (or weeks?) bevor providing support?

    If Analog Devices is not able to answer my question, please tell me.

    I will continue waiting for someone able to provide an, hopefully helpful, answer.

    Regards, Niels

  • +1
    •  Analog Employees 
    on Jul 22, 2020 3:45 PM 7 months ago in reply to Niels

    Thank you for your post.  The delay was inadvertent as I was notified just this morning of your post.  Normally I see posts right away, so I don't know what happened in this case.   I reported the issue with the LT3083 LTspice model - thank you also for that. This EZ post titled "Disable LT3083" discusses the parasitic diode from OUT to IN that you see on your hardware and the post also says how to identify the existence of parasitic diodes in this case by looking at the datasheet Abs. Max. table.   

  • 0 on Jul 22, 2020 4:03 PM 7 months ago in reply to ARad

    Hello ARad,

    this is not the answer I hoped for, but thank you anyway.
    What strategy do you suggest for adding a voltage blocking / reverse current protection functionality to the LT3083 output?
    As we talk about 3A, a simple schottky-diode waists quite a lot of power (0.4V * 3A = 1.2 W)

  • 0 on Jul 30, 2020 2:40 PM 6 months ago in reply to Niels

    No answer is also an answer. But which one?
    In this case I assume that the abcence of an answer to my last post shall indicate "If you have another question, open a new case. Even if your question arises from the outcome of this case."
    I suggest that you guys from Analog tell this to your customers insted of letting them guess after 8 days of silence.

  • 0
    •  Analog Employees 
    on Aug 19, 2020 1:51 AM 6 months ago in reply to Niels

    You could also consider a p-channel mosfet