Thermal Transient Testing: Hot Topics & Cool Applications

The topic is thermal transient testing: the T3ster-Way. Using information from transient tests we can achieve more than just temperature measurements in order to perform tests for quality, lifetime and materials. This ranges from low-power devices, such as MCUs, DSP and Small Diodes all the way to IGBTs, High brightness LEDs and MOSFETs – including their in-situ applications

23 May, 2014

Over the years, we have had some odd requests for our testing capabilities. Maybe they seemed odd for us, but normal for the requestee. One of those, which struck me as particularly interesting, was the request to test milk. Yes, that stuff that comes from cows.

Although I can’t get into further details on this one, that request brings me to my actual post.

As we were attending the PCIM in Nuremburg this week, we were reminiscing about past requests and noticed a lone bag of gummibears, that had found its way into my hand. We did not spare further thought on the logistics of the magical appearance, but started scheming something more sadistic and dark.

Coincedentally we had brought our newly developed 1500A Power Tester with us on that day. Again, not contemplating on how a 550kg piece of test equipment could magically appear, we continued down the dark road. (As a side note, if you sign a purchase order for a device, it will almost appear magically in your lab in exchange for some money.)

Nonetheless, a battle between good and evil ensued – comparable to the likes of Star Wars or Lord of the Rings. We captured one of the gummibears and decided that the ultimate sacrifice had to be made in the name of science. Strapping it on to the measurement channel, piercing the head with our measurement probes, the gummibear most likely thought it had been abducted by aliens. Fellow mates tried to stop the process from happening, but it was too late and we sent 1500A through the little guy. (No real animals were hurt during this test)

Finding the engineering solution to imprison a gummibear

Finding the engineering solution to imprison a gummibear

The result of confining a gummibear

The result of confining a gummibear

Creating a... Device?

That was the best thing we could come up with to describe a gummibear

That was the best thing we could come up with to describe a gummibear

Assigning the impending doom of a gummibear to a scientifically correct project folder

Assigning the impending doom of a gummibear to a scientifically correct project folder

Unfortunately we could not achieve clear results… But it was not all for naught! During our days at the PCIM we learnt many things, and got one clear message: Power Testing and Power Cycling combined with a thermal testing capability is something the industry is actively looking for. We now provide such a solution, and the resonance was astounding. If you would like some more information on this device, which may be equated to the physical manifestation hopes and dreams, then please check the link below.

http://www.mentor.com/products/mechanical/micred/power-tester-1500a

Friends of the victim trying to stop the process

Friends of the victim trying to stop the process

The bear survived

The bear survived

Check out the link to our power tester, and associated white paper!

http://www.mentor.com/products/mechanical/micred/power-tester-1500a

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14 May, 2014

As of late our Blog has become rather inactive. Not that we are not interested in writing anymore, but we are so. Darn. Busy. New products, new problems that need solving, and of course new ideas. However, it seems that there is a light at the end of the tunnel and there is a silhouette of a man that would like to welcome you to my first installation of our revived Blog. If the analogy doesn’t sit well with you, then it might be easier to picture me in a Lab Coat, engulfed by several LEDs, standing in a dimly lit hallway.

I am not entirely sure where my posts will be headed, but I believe it is a good thing. That means I can talk about anything I want, where it will ultimately result in some discussion for thermal problems. So maybe I am lying, when I say “anything”. I will actually only write about all the fun we can have with thermal transient testing and related topics. The blurb about me talking about saying anything I want, is actually only a disclaimer that you can’t hold all the bad jokes and puns against me.

However, as it has been a while since we spoke of thermal characterization, I think this is an opportune moment to get back into the basics. As in every discipline the basics are important… Or at least that is what my basketball coach would yell at me, before tossing his clipboard to the ground in a rage and making me run suicide drills. As I can’t force anyone to sprint (sadly), I will try to convey everything in an entertaining manner.

Thermal testing can be done in many ways. We know that. And for those who don’t, time to listen up! T3ster is based on the “Electrical Test Method”. The Electrical Test Method is also governed by the JEDEC JESD 51-1 Standard and has several advantages:

1. Uses intrinsic properties of semiconductors
2. Allows for a thermal characterization of device layers and systems
3. It is Non-Destructive

Though the word “Standard” sounds dry, long-wound and boring, It offers much valuable information on how the thermal test should be conducted, and some “under-the-hood” information for our T3ster Software. So, how do we conduct a good test?

The beginner might assume that it would suffice to wildly flap your hands at the device, and blow air at it until you collapse from a self-induced oxygen-high. But the more expert people amongst us would ask some questions first.

– What are the constraints (power, max temperature etc.)?
– What am I trying to measure? How will my testing time be affected?
– What is my maximum temperature difference I need
– Is it in-situ? Or a single device?
– What is the best way to set up my test in order to get the maximum data from it?

And last, but not least

– How do I evaluate my results in post-processing?

So, as this is my warm-up, I will already threaten you with the promise that I will discuss these questions, the general test method in upcoming posts and related thoughts. I hope you look forward hearing from me, as much as I look forward to hearing from myself.
Mathew Clark
Field Application Engineer – Europe

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