Hot-rod something else (if 3.5W max Pd isn't sufficient)
Example: VP0109N2 Cross to VP2206N2 P-Channel MosFET: In Stock Buy Now - West Florida Components
(full datasheet pdf at the bottom)
I've purchased it in pints I believe. Unfortunately, the hardeners come in a bottle which is enough for about a thousand gallons of the stuff.
24/23LV is what we use in cryo, it lowers viscosity of the mix an order of magnitude, cures room, but has a glass transition of about 45 C. Not good for hi temp electronics, great for liquid helium.
11 cures from 80 C up, glass transition of about 90. 9 cures room to 65, glass transition of 60 C.
The Tracon Bipax packs are pretty much the same thing, two part with alumina filler, parts separated by a clip. Pull the clip, knead the two components together, cut the tip of the tube.
Here's one. It has a TCE of 26 ppm/degree C, so it looks like it's heavily filled with alumina.
http://www.optosolutions.com/doc/Trabond2151.pdf
As to machining away the plastic..a reasonable idea, but the problem is the chip passivation. As a full surround on the bond pad of the chip, the encapsulation keeps integrity. Once you've exposed the copper backside, you've disconnected the full surround encapsulation, and it will debond away from the copper pad. If it continues to debond around the corner of the pad towards the die, then it opens the die surface to ionic contamination. I don't think any amount of glob top will help, and I don't know if they use it in the device. Needless to say, soldering heat applied to the exposed backside would probably destroy any bond between the encapsulation and the copper die tab. And if it's an activated flux, the zinc chloride activator will do the rest.
jn
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Both actually. But we still use helium to gain conductor capacity, LN2 to cool down to 50K.edit: we pull a vacuum so the LN2 boils down. It's 77K by itself..
Some of the guys are using the HTS tapes for energy storage, they've gone up to either 12 or 16 tesla so far. But I think even they use helium to gain current capacity.
NbTi, NbSn, and now MgB2 are still the best game in town for pure magnetic strength, and all use helium.
jn
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Maybe, we do plenty of chip on board (and leave the die bare) these days without issue. Passivation is at the point where bare die is no longer an issue.
The encapsulant might pull the die off of the copper if ground down but then the EPAD parts always have the backside exposed. I don't know if the encapsulant needs to be different.
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It hasn't been designed as yet. Just thought of it, today.
However, there is no reason I should give it to you, in any case.
OK Scott, work with JN to squeeze some heat out of the T0-92 cases.
Nelson, I think that a Freon heat exchanger is right up your area of interest? Sort of Rube-Goldberg and a great project for BurningAmp.
However, there is no reason I should give it to you, in any case.
OK Scott, work with JN to squeeze some heat out of the T0-92 cases.
Nelson, I think that a Freon heat exchanger is right up your area of interest? Sort of Rube-Goldberg and a great project for BurningAmp.
Yah, I'm probably showing my age. Had a few problems with bare SiO2 passivation back in the day, needed SIM's to find the problem. Don't know if the parts JC speaks of are SiO2 or nitride passivated. My 76 mm diodes used polyimide passivation, perhaps that's an option useable with aluminum wirebonds.
I assume that the EPAD devices have built in lock features on the sides of the copper. Perhaps if the leadframes were etched, the side profile might be sufficient to lock. If they were stamped, probably not..unless the stamping die had some half steps built in to create locking features.
Is the die JC needs available on EPAD?
I really still hate lead free for surface mount..temp too high, whiskers too possible..
jn
Lovely.
Why??? I see no reason I should give that to you...in any case.
jn
John JN, I appreciate your inputs on EMI, shielding and wiring. You are one of the very very few (unfortunately) who understand the issues. Many others, even big names, are just ignorants in this regard. Age and 50 years of "experience" does not help at all, obviously. 50 years ago there were not much troubles with EMI, probably.
No. BTW the next one will be a partial lunar eclipse, at about 20 hours UT on the 25th.
Well, PMA, you are probably right. I DON'T DO ENCLOSURES AND SHIELDING. Never have. I have always had others to help me with it, or just to do it entirely. This includes:
Power amps, preamps, analog studio recorders, multichannel mixing boards, pre-preamps, that go as low as 0.4nV/rt Hz and still don't seem to pick up hum too easily. Decades ago, I did work with some poor layout people and I DID have problems with hum pickup, etc, but they have been safely out of my way for about 30 years.
I do have a few textbooks on the subject, but I have never read them 'cover to cover'. Why should I? I have more interesting things to study.
Most people, including me, tend to develop our skills around what we are inherently good at. My primary 'skill' is circuit topology. That is really all that I do really well.
I have always worked with and I share credit with others for their 'skills', including circuit board layout, and case fabrication, including grounding and shielding.
IF IT WORKS WELL, I am happy with the result. Today, my CTC Blowtorch sits there, on 24 hours/day for more than 10 years, quietly, in every reasonable way, and so I am happy with it, and I TRY to show people here, what I know WORKS, whether it is because of my own personal input or that of my associates, especially the deceased ones. After all, keeping what works, completely private, does little to promote future audio quality.
When you, PMA, who is known to be 'skilled' at electronic engineering, RFI proofing, and circuit simulation, can also make a 'successful' audio product, independently verified by other experts in the audio evaluation field, then we will welcome you to the 'Society of Successful Audio Designers' like Nelson Pass, Charles Hansen and me, for example. Thanks for all you have contributed, so far.
Power amps, preamps, analog studio recorders, multichannel mixing boards, pre-preamps, that go as low as 0.4nV/rt Hz and still don't seem to pick up hum too easily. Decades ago, I did work with some poor layout people and I DID have problems with hum pickup, etc, but they have been safely out of my way for about 30 years.
I do have a few textbooks on the subject, but I have never read them 'cover to cover'. Why should I? I have more interesting things to study.
Most people, including me, tend to develop our skills around what we are inherently good at. My primary 'skill' is circuit topology. That is really all that I do really well.
I have always worked with and I share credit with others for their 'skills', including circuit board layout, and case fabrication, including grounding and shielding.
IF IT WORKS WELL, I am happy with the result. Today, my CTC Blowtorch sits there, on 24 hours/day for more than 10 years, quietly, in every reasonable way, and so I am happy with it, and I TRY to show people here, what I know WORKS, whether it is because of my own personal input or that of my associates, especially the deceased ones. After all, keeping what works, completely private, does little to promote future audio quality.
When you, PMA, who is known to be 'skilled' at electronic engineering, RFI proofing, and circuit simulation, can also make a 'successful' audio product, independently verified by other experts in the audio evaluation field, then we will welcome you to the 'Society of Successful Audio Designers' like Nelson Pass, Charles Hansen and me, for example. Thanks for all you have contributed, so far.
We use polyimide and something else I forgot mainly for stress relief and to prevent hysterysis from stick/slip friction.
BTW our chief packaging engineer credits me with introducing it here, I ground down and AD711 (1986) and showed him how scraping a probe needle across the top gave a nice offset vs stress crossplot.
Top of the die? Or top of the plastic.
I cringe to think of the aluminum smearing. Hexfets were especially troublesome with top smears, the polysilicon gate structure was easily damaged.
Sheesh, I hope you don't use EPADS for stress sensitive die..the die curvature introduced by a tin/silver backside attach would fry the offsets. I used to maintain at least 4 mils of lead/indium (155 C solidus) for shear mitigation on 400 mil square pads. Helped through mil spec temp cycling.
jn
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