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Question about Vout rise of LM4040BIM3-5.0

Satoshi
Guru 19485 points
Other Parts Discussed in Thread: LM4040

Circuit diagram is attached below.

On normal temp(25℃), Vout is 5V (normal opelation).

But, when LM4040 was cooled in -10℃, Vout rised 6V or 5.1V.

※It's different from 5.1V and 6V depending on devices.

 

Is this a problem of a circuit?

Or, is this defect drvice?

 

Best regards,

Satoshi

  • 0
    TI__Intellectual 1745 points
    Hi Satoshi,

    It is not immediately apparent to me what could be happening. If you could provide some more detail about the situation it may help. What is the input voltage range? Is the input voltage source affected at all during the cold cycling? How long does it take for Vref to change (ms, sec, minutes) once it reaches -10C? Does it get worse at colder temps?

    Regards,
    Chris
  • 0 in reply to Christopher Dean
    Guru 19485 points
    Dear Chris-san
    Thank you for reply.

    Additional information is below.

    -----------------------------------------------------------
    What is the input voltage range?
    ⇒15V
    Is the input voltage source affected at all during the cold cycling?
    ⇒Sorry, customer doesn't have these data.
    How long does it take for Vref to change (ms, sec, minutes) once it reaches -10C?
    ⇒30 minutes
    Does it get worse at colder temps?
    ⇒It's not get worse at colder temp.
    -----------------------------------------------------------

    Best regards,
    Satoshi
  • 0 in reply to Satoshi
    TI__Intellectual 1745 points

    Satoshi,

    Is there a way to isolate the part and test it by itself?  Is there any kind of frost or build up on the board anywhere, on the part or the Rset resistor etc.?  What does ground look like, is the ground affected by the cold?  

    -Chris