×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Jobs

Is it likely that surface mount resistors will burn out at 82C?
5

Is it likely that surface mount resistors will burn out at 82C?

Is it likely that surface mount resistors will burn out at 82C?

(OP)
Is it likely that surface mount resistors would burn out at 82C (180F) when they are not powered?  I do not have a datasheet for these; a general idea of what temperature different resistors typically burn out at would be helpful.

Thanks,

David

RE: Is it likely that surface mount resistors will burn out at 82C?

I really doubt it. Most common chip resistors have storage temperatures of at least 85C. And storage specs of 125C are very common.

RE: Is it likely that surface mount resistors will burn out at 82C?

The surface mount resistors I am familiar with should have no problem with a 82C non-operating (storage temperature).

Of course, a resistor operated in a ambient temperature of 82 C would have to be de-rated for it's power dissipation. The chart I have for this shows derating to about 85% of normal at this temperature. The chart I have in front of me (Venkel) shows at 150C the resistor has to be derated to about 25% of normal. If these resistors operate to these temperatures, the should be able to be stored (non-operating) at these temperatures.

RE: Is it likely that surface mount resistors will burn out at 82C?

How could they burn out at 82C if they are soldered at 250C?

Look at a data sheet you will get a feel for the subject.

Keith Cress
Flamin Systems, Inc.- http://www.flaminsystems.com

RE: Is it likely that surface mount resistors will burn out at 82C?

Sustained heat versus short time periods are different animals...

Dan - Owner
http://www.Hi-TecDesigns.com

RE: Is it likely that surface mount resistors will burn out at 82C?

You say they are burnt out, by which I assume you mean they measure open circuit? Have you checked for the possibility of hairline fractures in the surface mount resistor itself or its solder joints to the circuit board? Bad assembly procedures or subsequent bad handling of the board after soldering could produce an open circuit by one or other of these causes.


RE: Is it likely that surface mount resistors will burn out at 82C?

(OP)
Thanks for the feedback everyone.  I am not able to do much with these boards myself and am trying to understand if someone else has a reasonable concern.  

The conformal coating on the circuit boards has been changed and he is concerned about the resistors burning out at high temperature- he only wants to expose the boards to the high temperature though, not power them at high temperature.  

The exposure time is 7 days and I don't imagine the coating will change the temperature the board reaches.  Perhaps it will get there a bit faster... Any thoughts?

RE: Is it likely that surface mount resistors will burn out at 82C?

What temperature?????????????????????????????

And conformal coating surface mount parts will change their power dissipation ability during powered use, of course.

Keith Cress
Flamin Systems, Inc.- http://www.flaminsystems.com

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources