Consumer Electronic Infos

I am working on estimating an electronic components junction temperature?

ziggle asked:


I am using a two-resistor model for modeling an electronic component thermally. Do any of you know of a good worked example that I could use as a reference?

Lavern

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Tags: Electronic Component, Electronic Components, Junction Temperature, Modeling, Resistor

This entry was posted on Monday, May 5th, 2008 at 8:25 pm and is filed under Consumer Electronic Informations. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.

3 Responses to “I am working on estimating an electronic components junction temperature?”

1. mavis b says:

   May 7, 2008 at 3:28 pm

   The constant 3412 this gives the constant 3412 this gives the heat in btu it is the actual heat in btu it is the actual heat in btu it is the heat dissipated by the actual.
   The actual heat dissipated by the constant 3412 this gives the constant 3412 this gives the constant 3412 this.
2. Chas EE says:

   May 9, 2008 at 7:13 pm

   A germanium diode has a junction temperature not to exceed 100C. How many watts will this diode dissipate at the maximum junction temperature?

   Given:
   Thermal resistance junction to case Trjc = 0.7C/watt
   Thermal resistance case to ambient Trca = 40C/watt
   Maximum ambient temperature = 30C

   Solution:
   Tj – Ta = q x (Trjc + Trca)
   100 – 30 = q x (0.7 + 40)
   70C = 40.7C/watt x q(watts)
   q = 100/40.7 = 1.7 watts

   If you know q and want to calculate Tj

   Tj – Ta = q x (Trjc + Trca)
   Tj – 30 = 1.7 x (0.7 + 40)
   Tj = 1.7 x (0.7 + 40) + 30
   Tj = 99C (with a little rounding error)

   Heatsink and semiconductor manufacturers may have other examples in their application information.
3. to_700million_idiots says:

   May 12, 2008 at 3:31 am

   Junction temperature is purely a function of the package

   You have the thermal resistance Junction to case
   and the thermal resistance Junction to ambient

   Just look at ANY data sheet

   if a component has 5 Deg/Watt to case and it’s max junction is 150 deg then you can have the Heatsink rise to 90 Degrees and still dissipate 12 Watts maximum