Heatsink, just don't drop it on concrete

[Tim Williams]

https://www.digikey.com/product-detail/en/ohmite/CA-TX1-050-E/CA-TX1-050-E-ND/9954358

Damn, didn't realize they were making full heatsinks out of ceramic now.
Doesn't seem to be AlN either, just boring old Al2O3.

Performance looks comparable, despite the relatively low Rth of the material
(compared to AlN and Al). Not spendy either.

Tim

--
Seven Transistor Labs, LLC
Electrical Engineering Consultation and Design
Website: https://www.seventransistorlabs.com/

 

[boB]

On Mon, 17 Jun 2019 10:18:04 -0500, "Tim Williams"
<tiwill@seventransistorlabs.com> wrote:

https://www.digikey.com/product-detail/en/ohmite/CA-TX1-050-E/CA-TX1-050-E-ND/9954358

Damn, didn't realize they were making full heatsinks out of ceramic now.
Doesn't seem to be AlN either, just boring old Al2O3.

Performance looks comparable, despite the relatively low Rth of the material
(compared to AlN and Al). Not spendy either.

Tim

Sure, why not I guess...

They make power resistors out of the stuff

 

[Joerg]

On 2019-06-17 08:18, Tim Williams wrote:

https://www.digikey.com/product-detail/en/ohmite/CA-TX1-050-E/CA-TX1-050-E-ND/9954358


Damn, didn't realize they were making full heatsinks out of ceramic now.
Doesn't seem to be AlN either, just boring old Al2O3.

Performance looks comparable, despite the relatively low Rth of the
material (compared to AlN and Al). Not spendy either.

95% Al2O3, so what's the other stuff in there? Doesn't look like the
solder feet make up 5%.

And hey, they filed a patent for a laundry clip

Come to think of it, one should be able to clip wet socks underneath
there and then dry them.

--
Regards, Joerg

http://www.analogconsultants.com/

 

[Phil Hobbs]

On 6/17/19 11:18 AM, Tim Williams wrote:

https://www.digikey.com/product-detail/en/ohmite/CA-TX1-050-E/CA-TX1-050-E-ND/9954358


Damn, didn't realize they were making full heatsinks out of ceramic now.
Doesn't seem to be AlN either, just boring old Al2O3.

Performance looks comparable, despite the relatively low Rth of the
material (compared to AlN and Al).  Not spendy either.

Tim

Eight bucks for a 1x2 inch heatsink "isn't spendy"? Aluminum ones run
maybe 80 cents in onesies on Digikey.

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC / Hobbs ElectroOptics
Optics, Electro-optics, Photonics, Analog Electronics
Briarcliff Manor NY 10510

http://electrooptical.net
http://hobbs-eo.com

 

[Joerg]

On 2019-06-17 16:29, Phil Hobbs wrote:

On 6/17/19 11:18 AM, Tim Williams wrote:
https://www.digikey.com/product-detail/en/ohmite/CA-TX1-050-E/CA-TX1-050-E-ND/9954358


Damn, didn't realize they were making full heatsinks out of ceramic
now. Doesn't seem to be AlN either, just boring old Al2O3.

Performance looks comparable, despite the relatively low Rth of the
material (compared to AlN and Al). Not spendy either.

Tim


Eight bucks for a 1x2 inch heatsink "isn't spendy"? Aluminum ones run
maybe 80 cents in onesies on Digikey.

But it does have its bling factor. Just imagine the unfettered flow of
electrons in a class D stage, using space-age ceramic technology for the
ultimate sound experience

--
Regards, Joerg

http://www.analogconsultants.com/

 

[John Larkin]

On Mon, 17 Jun 2019 16:37:21 -0700, Joerg <news@analogconsultants.com>
wrote:

On 2019-06-17 16:29, Phil Hobbs wrote:
On 6/17/19 11:18 AM, Tim Williams wrote:
https://www.digikey.com/product-detail/en/ohmite/CA-TX1-050-E/CA-TX1-050-E-ND/9954358


Damn, didn't realize they were making full heatsinks out of ceramic
now. Doesn't seem to be AlN either, just boring old Al2O3.

Performance looks comparable, despite the relatively low Rth of the
material (compared to AlN and Al). Not spendy either.

Tim


Eight bucks for a 1x2 inch heatsink "isn't spendy"? Aluminum ones run
maybe 80 cents in onesies on Digikey.


But it does have its bling factor. Just imagine the unfettered flow of
electrons in a class D stage, using space-age ceramic technology for the
ultimate sound experience

I'm skeptical about the cooling, but it would be nice for high
voltage.

Real bling and real cooling would be solid diamond.


--

John Larkin Highland Technology, Inc
picosecond timing precision measurement

jlarkin att highlandtechnology dott com
http://www.highlandtechnology.com

 

[Winfield Hill]

Joerg wrote...

On 2019-06-17 16:29, Phil Hobbs wrote:
On 6/17/19 11:18 AM, Tim Williams wrote:

Performance looks comparable, despite the relatively
low Rth of the material (compared to AlN and Al).
Not spendy either.

Eight bucks for a 1x2 inch heatsink "isn't spendy"?
Aluminum ones run maybe 80 cents in onesies on Digikey.

But it does have its bling factor. Just imagine the
unfettered flow of electrons in a class D stage,
using space-age ceramic technology for the ultimate
sound experience

I struggle with the high heatsink capacitance of power
transistor tabs. $7 is cheap at the price for s solution.
Wanna make a 500V/us fast-slewing HV amplifier stage?
Find a low-C power part, and a low-C heatsink.
Read all about it in the soon-to-be-out AoE x-Chapters.


--
Thanks,
- Win

 

[Tim Williams]

"Phil Hobbs" <pcdhSpamMeSenseless@electrooptical.net> wrote in message
news:9sWdnapK4K78v5XAnZ2dnUU7-d3NnZ2d@supernews.com...

Eight bucks for a 1x2 inch heatsink "isn't spendy"? Aluminum ones run
maybe 80 cents in onesies on Digikey.

No offense Phil, but I somehow doubt even you can bootstrap the capacitance
of a heatsink in a sufficiently high frequency switcher. ;-)

Cheap compared to the outright infeasibility of something, or compared to
more exotic materials (AlN, BeO).

Tim

--
Seven Transistor Labs, LLC
Electrical Engineering Consultation and Design
Website: https://www.seventransistorlabs.com/

 

[Jan Panteltje]

On a sunny day (Mon, 17 Jun 2019 19:29:35 -0400) it happened Phil Hobbs
<pcdhSpamMeSenseless@electrooptical.net> wrote in
<9sWdnapK4K78v5XAnZ2dnUU7-d3NnZ2d@supernews.com>:

On 6/17/19 11:18 AM, Tim Williams wrote:
https://www.digikey.com/product-detail/en/ohmite/CA-TX1-050-E/CA-TX1-050-E-ND/9954358


Damn, didn't realize they were making full heatsinks out of ceramic now.
Doesn't seem to be AlN either, just boring old Al2O3.

Performance looks comparable, despite the relatively low Rth of the
material (compared to AlN and Al).  Not spendy either.

Tim


Eight bucks for a 1x2 inch heatsink "isn't spendy"? Aluminum ones run
maybe 80 cents in onesies on Digikey.

Cheers

Phil Hobbs

Dunno. mostly profit.
a quick search for ceramic heatsink on ebay
finds many for Raspberry 3B+ at 99 cents.
OK, smaller, no pins, but material cost?
https://www.ebay.com/itm/333190430314

Could have some advantages.

 

[John Larkin]

On Mon, 17 Jun 2019 21:42:52 -0500, "Tim Williams"
<tiwill@seventransistorlabs.com> wrote:

"Phil Hobbs" <pcdhSpamMeSenseless@electrooptical.net> wrote in message
news:9sWdnapK4K78v5XAnZ2dnUU7-d3NnZ2d@supernews.com...

Eight bucks for a 1x2 inch heatsink "isn't spendy"? Aluminum ones run
maybe 80 cents in onesies on Digikey.


No offense Phil, but I somehow doubt even you can bootstrap the capacitance
of a heatsink in a sufficiently high frequency switcher. ;-)

Cheap compared to the outright infeasibility of something, or compared to
more exotic materials (AlN, BeO).

Tim

I'm buying Chinese custom-fabbed AlN insulators, for TO247 SiC fets,
for a dollar or so.

https://www.dropbox.com/s/1991iiogop8mgnk/JRFT_AlN_1.jpg?raw=1

It's TO220 size roughly, but I'm cooling a TO247. Smaller insulator
makes less capacitance.

I really want diamond.


--

John Larkin Highland Technology, Inc

lunatic fringe electronics

 

[John Larkin]

On 17 Jun 2019 18:40:30 -0700, Winfield Hill <winfieldhill@yahoo.com>
wrote:

Joerg wrote...

On 2019-06-17 16:29, Phil Hobbs wrote:
On 6/17/19 11:18 AM, Tim Williams wrote:

Performance looks comparable, despite the relatively
low Rth of the material (compared to AlN and Al).
Not spendy either.

Eight bucks for a 1x2 inch heatsink "isn't spendy"?
Aluminum ones run maybe 80 cents in onesies on Digikey.

But it does have its bling factor. Just imagine the
unfettered flow of electrons in a class D stage,
using space-age ceramic technology for the ultimate
sound experience

I struggle with the high heatsink capacitance of power
transistor tabs. $7 is cheap at the price for s solution.
Wanna make a 500V/us fast-slewing HV amplifier stage?
Find a low-C power part, and a low-C heatsink.
Read all about it in the soon-to-be-out AoE x-Chapters.

An AlN insulator over a water-cooled aluminum or copper block is
pretty good for cooling vs capacitance. Flowing water directly onto
the fet tab would be a lot better.


--

John Larkin Highland Technology, Inc

lunatic fringe electronics

 

[Tim Williams]

"Winfield Hill" <winfieldhill@yahoo.com> wrote in message
news:qe9fee01pod@drn.newsguy.com...

I struggle with the high heatsink capacitance of power
transistor tabs. $7 is cheap at the price for s solution.
Wanna make a 500V/us fast-slewing HV amplifier stage?
Find a low-C power part, and a low-C heatsink.
Read all about it in the soon-to-be-out AoE x-Chapters.

Y'know, I'll bet it's transparent to long IR as well. Not that there's much
to see on the metal backside of a transistor or what have you, but it may be
useful sometimes. A sil-pad would definitely be emissive, grease may be as
well.

Tim

--
Seven Transistor Labs, LLC
Electrical Engineering Consultation and Design
Website: https://www.seventransistorlabs.com/

 

[Jan Panteltje]

On a sunny day (Mon, 17 Jun 2019 16:37:21 -0700) it happened Joerg
<news@analogconsultants.com> wrote in <gmqmgvF4csnU1@mid.individual.net>:

On 2019-06-17 16:29, Phil Hobbs wrote:
On 6/17/19 11:18 AM, Tim Williams wrote:
https://www.digikey.com/product-detail/en/ohmite/CA-TX1-050-E/CA-TX1-050-E-ND/9954358


Damn, didn't realize they were making full heatsinks out of ceramic
now. Doesn't seem to be AlN either, just boring old Al2O3.

Performance looks comparable, despite the relatively low Rth of the
material (compared to AlN and Al). Not spendy either.

Tim


Eight bucks for a 1x2 inch heatsink "isn't spendy"? Aluminum ones run
maybe 80 cents in onesies on Digikey.


But it does have its bling factor. Just imagine the unfettered flow of
electrons in a class D stage, using space-age ceramic technology for the
ultimate sound experience

Would be a real brick wall filter

 

[Jan Panteltje]

On a sunny day (Mon, 17 Jun 2019 21:02:38 -0700) it happened John Larkin
<jjlarkin@highlandtechnology.com> wrote in
<uhoggehbfa6gbmevhg9u00d5duvicqdarv@4ax.com>:

On Tue, 18 Jun 2019 03:41:57 GMT, Jan Panteltje
pNaOnStPeAlMtje@yahoo.com> wrote:

On a sunny day (Mon, 17 Jun 2019 19:29:35 -0400) it happened Phil Hobbs
pcdhSpamMeSenseless@electrooptical.net> wrote in
9sWdnapK4K78v5XAnZ2dnUU7-d3NnZ2d@supernews.com>:

On 6/17/19 11:18 AM, Tim Williams wrote:
https://www.digikey.com/product-detail/en/ohmite/CA-TX1-050-E/CA-TX1-050-E-ND/9954358


Damn, didn't realize they were making full heatsinks out of ceramic now.
Doesn't seem to be AlN either, just boring old Al2O3.

Performance looks comparable, despite the relatively low Rth of the
material (compared to AlN and Al).  Not spendy either.

Tim


Eight bucks for a 1x2 inch heatsink "isn't spendy"? Aluminum ones run
maybe 80 cents in onesies on Digikey.

Cheers

Phil Hobbs

Dunno. mostly profit.
a quick search for ceramic heatsink on ebay
finds many for Raspberry 3B+ at 99 cents.
OK, smaller, no pins, but material cost?
https://www.ebay.com/itm/333190430314

Could have some advantages.

Probably thermally useless.

I do not think so, that particular raspi had a big thermal problem
later fixed IIRC.
Those thing must really work?

 

[Rick C]

On Monday, June 17, 2019 at 6:42:05 PM UTC-4, Joerg wrote:

On 2019-06-17 08:18, Tim Williams wrote:
https://www.digikey.com/product-detail/en/ohmite/CA-TX1-050-E/CA-TX1-050-E-ND/9954358


Damn, didn't realize they were making full heatsinks out of ceramic now.
Doesn't seem to be AlN either, just boring old Al2O3.

Performance looks comparable, despite the relatively low Rth of the
material (compared to AlN and Al). Not spendy either.


95% Al2O3, so what's the other stuff in there? Doesn't look like the
solder feet make up 5%.

And hey, they filed a patent for a laundry clip

Come to think of it, one should be able to clip wet socks underneath
there and then dry them.

I think it is similar compounds with other metals than Aluminum. I seem to recall this stuff is also very temperature stable, but has to be a lot more pure, <1% impurities, but I may be thinking of silica.

--

Rick C.

++- Get 1,000 miles of free Supercharging
++- Tesla referral code - https://ts.la/richard11209

 

[John Larkin]

On Tue, 18 Jun 2019 03:41:57 GMT, Jan Panteltje
<pNaOnStPeAlMtje@yahoo.com> wrote:

On a sunny day (Mon, 17 Jun 2019 19:29:35 -0400) it happened Phil Hobbs
pcdhSpamMeSenseless@electrooptical.net> wrote in
9sWdnapK4K78v5XAnZ2dnUU7-d3NnZ2d@supernews.com>:

On 6/17/19 11:18 AM, Tim Williams wrote:
https://www.digikey.com/product-detail/en/ohmite/CA-TX1-050-E/CA-TX1-050-E-ND/9954358


Damn, didn't realize they were making full heatsinks out of ceramic now.
Doesn't seem to be AlN either, just boring old Al2O3.

Performance looks comparable, despite the relatively low Rth of the
material (compared to AlN and Al).  Not spendy either.

Tim


Eight bucks for a 1x2 inch heatsink "isn't spendy"? Aluminum ones run
maybe 80 cents in onesies on Digikey.

Cheers

Phil Hobbs

Dunno. mostly profit.
a quick search for ceramic heatsink on ebay
finds many for Raspberry 3B+ at 99 cents.
OK, smaller, no pins, but material cost?
https://www.ebay.com/itm/333190430314

Could have some advantages.

Probably thermally useless.


--

John Larkin Highland Technology, Inc

lunatic fringe electronics

 

[boB]

On Tue, 18 Jun 2019 04:42:39 GMT, Jan Panteltje
<pNaOnStPeAlMtje@yahoo.com> wrote:

On a sunny day (Mon, 17 Jun 2019 21:02:38 -0700) it happened John Larkin
jjlarkin@highlandtechnology.com> wrote in
uhoggehbfa6gbmevhg9u00d5duvicqdarv@4ax.com>:

On Tue, 18 Jun 2019 03:41:57 GMT, Jan Panteltje
pNaOnStPeAlMtje@yahoo.com> wrote:

On a sunny day (Mon, 17 Jun 2019 19:29:35 -0400) it happened Phil Hobbs
pcdhSpamMeSenseless@electrooptical.net> wrote in
9sWdnapK4K78v5XAnZ2dnUU7-d3NnZ2d@supernews.com>:

On 6/17/19 11:18 AM, Tim Williams wrote:
https://www.digikey.com/product-detail/en/ohmite/CA-TX1-050-E/CA-TX1-050-E-ND/9954358


Damn, didn't realize they were making full heatsinks out of ceramic now.
Doesn't seem to be AlN either, just boring old Al2O3.

Performance looks comparable, despite the relatively low Rth of the
material (compared to AlN and Al).  Not spendy either.

Tim


Eight bucks for a 1x2 inch heatsink "isn't spendy"? Aluminum ones run
maybe 80 cents in onesies on Digikey.

Cheers

Phil Hobbs

Dunno. mostly profit.
a quick search for ceramic heatsink on ebay
finds many for Raspberry 3B+ at 99 cents.
OK, smaller, no pins, but material cost?
https://www.ebay.com/itm/333190430314

Could have some advantages.

Probably thermally useless.

I do not think so, that particular raspi had a big thermal problem
later fixed IIRC.
Those thing must really work?

What's the thermal resistance of this kind of stuff ?

Ceramic resistors come to mind. If it really works OK but not as
good as aluminum, then it might have an advantage like Win says
about the capacitance and could help common mode noise issues that
happen with aluminum heat sinks.

Can't make aluminim castings out of the stuff. Or can you ?

 

[Winfield Hill]

John Larkin wrote...

Winfield Hill wrote:
Joerg wrote...
Phil Hobbs wrote:
Tim Williams wrote:

Performance looks comparable, despite the relatively
low Rth of the material (compared to AlN and Al).
Not spendy either.

Eight bucks for a 1x2 inch heatsink "isn't spendy"?
Aluminum ones run maybe 80 cents in onesies on Digikey.

But it does have its bling factor. Just imagine the
unfettered flow of electrons in a class D stage,
using space-age ceramic technology for the ultimate
sound experience

I struggle with the high heatsink capacitance of power
transistor tabs. $7 is cheap at the price for s solution.
Wanna make a 500V/us fast-slewing HV amplifier stage?
Find a low-C power part, and a low-C heatsink.
Read all about it in the soon-to-be-out AoE x-Chapters.

An AlN insulator over a water-cooled aluminum or copper
block is pretty good for cooling vs capacitance. Flowing
water directly onto the fet tab would be a lot better.

Yep, I'd have much less struggle with my thermal
problems, if my whole circuit was in an oil bath.


--
Thanks,
- Win

 

[Tim Williams]

"boB" <boB@K7IQ.com> wrote in message
news:hg1hgets7j8d6gragielv0c5nudbtl75cj@4ax.com...

What's the thermal resistance of this kind of stuff ?

About 30 W/m.K. Not great, but comparable to a lot of metals, and still way
better than air.

Ceramic resistors come to mind. If it really works OK but not as
good as aluminum, then it might have an advantage like Win says
about the capacitance and could help common mode noise issues that
happen with aluminum heat sinks.

Can't make aluminim castings out of the stuff. Or can you ?

My guess is they're HIPing it with a very carefully shaped die. I wonder if
it can be extruded perfectly prismatic, or if the die needs to be shaped in
such a way that the powder compacts and shrinks as it moves through.

Apparently sapphire can be extruded as well, from a crucible with a
carefully shaped lid (Czochralski process). That would be a little too
fancy for a heatsink, though...

Casting is much less impressive for ceramics. You make a slip with water,
suspension agents (deflocculant) and gum. Pour into a porous mold, the
water gets sucked out from the surface, then either let it continue or pour
out the excess to make a hollow form. Open mold and let dry, then fire.
The powder has no stiction by itself (unlike clay), which is where the gum
comes in: a binder is used, that is soluble in water, that doesn't form a
skin as it dries, and which pyrolyzes to substances that are still sticky,
without also expanding in the process. That way, the green ceramic body can
go straight into the kiln without crumbling to dust.

Pressed shapes are more common I think, other than HIP extruded shapes.
Ceramic powder and a bit of binder, no water needed. Make mold 10% or so
oversized, since it shrinks about that much on firing.

Tim

--
Seven Transistor Labs, LLC
Electrical Engineering Consultation and Design
Website: https://www.seventransistorlabs.com/

 

[George Herold]

On Monday, June 17, 2019 at 9:40:44 PM UTC-4, Winfield Hill wrote:

Joerg wrote...

On 2019-06-17 16:29, Phil Hobbs wrote:
On 6/17/19 11:18 AM, Tim Williams wrote:

Performance looks comparable, despite the relatively
low Rth of the material (compared to AlN and Al).
Not spendy either.

Eight bucks for a 1x2 inch heatsink "isn't spendy"?
Aluminum ones run maybe 80 cents in onesies on Digikey.

But it does have its bling factor. Just imagine the
unfettered flow of electrons in a class D stage,
using space-age ceramic technology for the ultimate
sound experience

I struggle with the high heatsink capacitance of power
transistor tabs. $7 is cheap at the price for s solution.
Wanna make a 500V/us fast-slewing HV amplifier stage?
Find a low-C power part, and a low-C heatsink.
Read all about it in the soon-to-be-out AoE x-Chapters.

Not that it really matters, but do you have a price point for the
X-chapters? (Seems like less sales volume than AoE3, so more $.)
And will it be reading for beach reading this summer?
(before July 4th say.)

George H.

--
Thanks,
- Win