EEVblog Electronics Community Forum

Electronics => Repair => Topic started by: cvanc on July 24, 2019, 02:21:57 pm

Title: Confused about thermal pad specifications
Post by: cvanc on July 24, 2019, 02:21:57 pm

See photo, please.  Let me ask the questions this way:

Under 'Thermal Resistivity' which one is best?
Under 'Thermal Conductivity' which one is best?
Which of these parameters is directly related to this specific part in question (material plus dimensions)?
Which of these parameters is directly related to the MATERIAL the part is made from, as a dimensionless spec?

Thanks.

Title: Re: Confused about thermal pad specifications
Post by: PKTKS on July 24, 2019, 04:45:52 pm

Well tables are just inverted.. you pick your choice.

I rather prefer the CONDUCTANCE in both senses:

- First a more thermal CONDUCTIVE pad is better
- second the material MUST BE carefully considered.

You see as in THERMAL PASTE - thermal pads may be used
where some capacitors are underneath components and will not
tolerate CONDUCTIVE (electric) material.

I have seen some pads literally melt becoming a garbage
crap underneath the component.

If the material is conductive (electric) bad things happen

Paul

Title: Re: Confused about thermal pad specifications
Post by: wraper on July 24, 2019, 05:14:46 pm

Thermal resistivity = 1/Thermal conductivity. Same thing. Lower resistivity/higher conductivity is better.