Cold spray, where do you buy?

I prefer the heat gun. Less of a stench :-)

That's roughly what I had on CMOS switches as well. So I servoed them (somewhat), using another one on the same die in a DC loop. Worked quite well but it didn't have to be perfect in my cases.

You must be buying cheap French freeze spray. "Winter in Paris" maybe.

We generally use an LM45 or an LM71 temp sensor and do the tc comps in software, occasionally analog in hardware. Reducing prop delay tc by maybe 5:1 is reasonable without temperature cycling production units.

John

r152a refrigerant, looks like it is atleast somewhat flammable the nonflammble freeze spray is r134a refrigerant.

considering that is has a gpw in the hundreds(r152a) and thousands(r134a), it is amazing that you can still buy the stuff for use as a freeze spray

-Lasse

Now if they'd put a "Harley Davidson" aftershave scent in it, that would be ok.

I always wondered why FPGA don't have a feature to program an on-chip temperature sensor onto one pin, or at least a diode path. uC often have that, for example the MSP430 series.

Yeah, that would be great. It could also be SPI or just a register you could read.

John

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looks like virtex5 has that and more:

It should speed up.

ECL also has a positive speed/temperature coefficient. We used insulators under the Thermal Conduction Modue pistons of low power chips to equalize the junction temperature of all chips at 85C.

I've used one of those rechargers on a car. The valve is nothing more than a pointed screw that stabs a hole in the canister's top. It turns off just well enough that you can disconnect the hose without losing fingers. The can will leak itself empty in a day or less.

I'd go for a duster can upside down. For longer term use, tech stores catering to gamers sell all kinds of forced liquid cooling systems involving peltier or freon heat pumps. I haven't bought one but it looks like they use plain vinyl hoses that can be made any length.

The Actel Fusion family can do pretty temperature measurements, but they are ... a bit expensive. Maybe a ring oscillator in the FPGA fabric, with the output frequency compared to a stable external oscillator, can help ?

yg

Exactly right. The Perfect Data duster I have uses the same propellant, but doesn't have the nasty. It does leave a quite noticable residue, so it might affect analog circuits.

Bittering Agent

What is Bittering Agent?

Bittering agent is an additive that leaves a bitter taste upon contact with one?s mouth. 3M added a bittering agent to 3M Dust Remover to help discourage inhalation abuse. The bittering agent itself is generally not harmful and is used in household cleaners and shampoos to deter intentional or accidental ingestion of these products. However? people with asthma or sensitivity to odors or taste may react to the bittering agent? and therefore? may want to avoid using 3M Dust Remover.

Abuse by inhaling 3M Dust Remover may cause instant death or injury.

How do I get the bittering agent bad taste out of my mouth?

Dried liquid spray may leave a bitter residue? resulting in a bad taste if transferred to the mouth. If you eat a piece of chocolate? or drink or eat some dairy products? it may help the taste to go away.

How do I get the bittering agent off my fingers?

Wash affected area with soap and water. If irritation occurs? get medical attention. ALWAYS hold container upright to avoid spraying liquid. Dried liquid spray may leave a bitter residue.

How do I get the bittering agent off my keyboard?

To remove dried spray? wipe with a cloth dampened with a 50/50 mix of isopropyl alcohol and water. ALWAYS hold container upright to avoid spraying liquid. Dried liquid spray may leave a bitter residue.

Can I buy 3M Dust Remover that does not contain the bittering agent?

No. All 3M Dust Remover currently sold contains a bittering agent.

Best regards, Spehro Pefhany

Slightly off topic but interesting if you are doing a lot of local cooling:

"It" referring to the 3M product with bitterant, of course, and noticable by humans perhaps not by circuits.

Here is info on the substance they are likely using:

Best regards, Spehro Pefhany

Given that the clock is usually derived from an XO, you could make a ring oscillator, divide it down, and measure its frequency (it's easy to build a frequency counter!) against the clock, compute an error, make a delta-sigma DAC, and servo the external core power supply to correct. That should flatten out the gate prop delay tc pretty well, although different routing delays will still have different TCs.

I guess routing delay TCs are the nasty problem.

How come so many posters here have no name, or an obviously bogus one?

John

We tried a vortex tube and were disappointed. Not much cooling and

John

I've got a commercial one that I was just (in the last 30 seconds!) playing with. It has a sort of muffler on the hot air output port, but is still pretty noisy and uses a lot of air volume (but I was expecting that). I think I might have a real application for it (first time since finding Ranque-Hilsh (actually they only credited the latter) in an old Amateur Scientist column decades ago)- but it's oddball in that the air is there and comes almost for free.

Best regards, Spehro Pefhany

Sure, but then you have to measure frequency and, for some applications, you've just created another EMI nightmare. A simple diode path is all that's needed. In just about any chip design review I suggest this because the feature is essentially free. What follows is usually a moment of silence followed by someone saying "Oh yeah, let's do that".

That's what my client described. He said it's sort of like the "bitter apple" stuff that you put on things that your dog wants to chew but isn't supposed to.

Would it be enough to disgnose thermal effects in a chip? Then we'd just have to wait until Harborfreight has it :-)

So? If you have a small compressor adjacent to your lab, just build a Hilsch tube? ...Jim Thompson