Silicone VS mica pads - pros/cons?

Wavebourn · 16th October 2006, 08:19 PM

I traditionally use mica pads, but more and more I see silicone pads under transistors. What are resulting thermal resistances, if to compare?

Netlist · 16th October 2006, 08:44 PM

Here's an interesting thread about the subject.

/Hugo

Wavebourn · 16th October 2006, 09:54 PM

Quote:

Originally posted by Netlist
Here's an interesting thread about the subject.

/Hugo

Thanks Hugo, great topic!!!

XEAGLEKEEPER · 22nd October 2006, 04:18 PM

Has anyone ever used beryllium oxide isolators ? Beryllium oxide is carcinogenic and poses health risks if inhaled. I know it is used in traveling wave tubes TWT's for rapid heat transfer to cold plates in Hi-power RF amplifiers( mil-aircraft). Any thoughts ?

EUVL · 22nd October 2006, 04:37 PM

Beryllia is great stuff, even better than Aluminium Nitride. If you know a source to get thin substrates at affordable prices, please let us know.

But then diamond is even better, isn't it ?

Patrick

Wavebourn · 22nd October 2006, 05:55 PM

Quote:

Originally posted by XEAGLEKEEPER
Has anyone ever used beryllium oxide isolators ? Beryllium oxide is carcinogenic and poses health risks if inhaled. I know it is used in traveling wave tubes TWT's for rapid heat transfer to cold plates in Hi-power RF amplifiers( mil-aircraft). Any thoughts ?

I used berillium ceramic for hybrid ICs. Also, long time ago I had mil spec TO-3 pads made of berillium ceramic. But I don't remember details.

Why I started the thread, silicone pads look attractive, and I wandered, what if to use them instead of mica pads.

john_ellis · 22nd October 2006, 06:19 PM

Hi all

see my note on the Pass Labs thread, mentioned "here" by Hugo.

John

AndrewT · 22nd October 2006, 07:39 PM

Hi Wave,
they are not silicone pads.

Try using some other names in your searching.

Stocker · 22nd October 2006, 08:13 PM

Quote:

Originally posted by EUVL

But then diamond is even better, isn't it ?

Patrick

hey can I borrow your CVD chamber to lay a coat of diamond on my anodized heatsink?

BlackCatSound · 22nd October 2006, 10:04 PM

Bergquist make kapton and also Boron nitride loaded silicon pre-cut transistor insulators.

5-6x the thermal conductivity of the gray rubbery pads, but about the same increase in cost.

Still, FAR cleaner than any of the thermal goops.

16th October 2006, 08:19 PM	#1
Wavebourn diyAudio Member Join Date: Sep 2006 Location: Pleasant Hill, CA	Silicone VS mica pads - pros/cons? I traditionally use mica pads, but more and more I see silicone pads under transistors. What are resulting thermal resistances, if to compare? __________________ The devil is not so terrible as his mathematical model! Wavebourn: We Create Creativity!

22nd October 2006, 04:18 PM	#4
XEAGLEKEEPER diyAudio Member Join Date: Jan 2006 Location: central Iowa	Has anyone ever used beryllium oxide isolators ? Beryllium oxide is carcinogenic and poses health risks if inhaled. I know it is used in traveling wave tubes TWT's for rapid heat transfer to cold plates in Hi-power RF amplifiers( mil-aircraft). Any thoughts ? __________________ Ret. USAF... AKA- Avionic * Solder slinger for hire...*

22nd October 2006, 07:39 PM	#8
AndrewT diyAudio Member Join Date: Jul 2004 Location: Scottish Borders	Hi Wave, they are not silicone pads. Try using some other names in your searching. __________________ regards Andrew T.

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16th October 2006, 08:44 PM	#2
Netlist diyAudio Moderator Join Date: Jan 2003	Here's an interesting thread about the subject. /Hugo

22nd October 2006, 04:37 PM	#5
EUVL diyAudio Member Join Date: Oct 2003	Beryllia is great stuff, even better than Aluminium Nitride. If you know a source to get thin substrates at affordable prices, please let us know. But then diamond is even better, isn't it ? Patrick

22nd October 2006, 06:19 PM	#7
john_ellis diyAudio Member Join Date: Sep 2006	Hi all see my note on the Pass Labs thread, mentioned "here" by Hugo. John

22nd October 2006, 10:04 PM	#10
BlackCatSound diyAudio Member Join Date: Oct 2004	Bergquist make kapton and also Boron nitride loaded silicon pre-cut transistor insulators. 5-6x the thermal conductivity of the gray rubbery pads, but about the same increase in cost. Still, FAR cleaner than any of the thermal goops.

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