Looking for high power TTV for TIM testing...
Looking for high power TTV for TIM testing...
(OP)
Hey guys. I'm trying to find a commercially available thermal test vehicle with built in temperature monitoring to test thermal interface solutions. I need something fairly high power, like 100W minimum over a 20mm x 20mm area. Is there anything out there? All I have been able to find are tests done on proprietary equipment.





RE: Looking for high power TTV for TIM testing...
Keith Cress
Flamin Systems, Inc.- http://www.flaminsystems.com
RE: Looking for high power TTV for TIM testing...
RE: Looking for high power TTV for TIM testing...
Let me suggest a new DUO CORE Intel processor. Why? Because over the years motherboard CPU temp monitoring has gone from nil to absolutely great! After no sensing, came socket sensing where some temp sensor was incorporated into the CPU socket. It measured the bottom of the chip carrier and only allowed vague inference of the heat sink performance.
Next they decided to put the sensor onto the actual IC. This would then be read by circuitry on the motherboard and dealt with by the BIOS. This was much closer to the right solution. The problem though was variation between motherboards and the characteristic of the substrate sensor. This meant the actual temp was +/-15C which is easily the difference between disaster and happy-happy-joy-joy. This caused a ton of overclockers to make claims of Intel because they "never reached the temperature limit" but the CPU still died. In reality they had exceeded the limit and fried the CPU but the temperature monitoring system was just flat wrong.
With the shrinking of the die and the inclusion of multiple cores exaserbating the whole heat problem Intel decided to fix this niggling problem once and for all. Clever really, because if the overclockers have a 'good' tool they won't be frying their CPUs and making claims because NOBODY wants to fry their CPUs.
So they included a die sensor on each core of a multicore CPU and they included the A/D on each die to read the core temperature and they even calibrate them.
All you need to do is read a certain register in the CPU to get the latest instantaneous calibrated CPU die temperature.
The computer I'm writing this on has this feature. It's a Duo Core 6700. I run a small program that constantly shows both core temps. Just by grabbing a window and wiggling it I can see the resulting near instant temp rise that is caused by the extra processing it takes to process the translated image. The instant I stop wiggling a window the temp drops back. A lot of fun actually.
The only gotcha is that a lot of these transition motherboards still try to read the CPU temp via the motherboard scheme and so are reporting bazaar temp values that cause things like over heat alarms to go active. Just be aware.
Anyway if you use a motherboard and one of the latest CPUs with the temp reading utility you will have a nice accurate reading of the die temp. Add a system watt-meter. Write some software to change the CPU loading automatically. Log the test regime result. Voila!
Keith Cress
Flamin Systems, Inc.- http://www.flaminsystems.com
RE: Looking for high power TTV for TIM testing...
There are many touchy variables in TIM testing: the attachment force, component height, planarity, and heat sink surface conditions have large tolerance ranges (even if you clean and re-use a sink, the behavior can change!). You'll need to run a lot of tests to get statistically significant results.
You can embed a thermocouple in the heat sink so you don't have to worry about sink-to-air test variations. Consistently locating and mounting this is a whole nother subject...
TIM mfgrs usually avoid these issues by testing to a standard like ASTM D374 and telling customers "your results may vary".
ko (www.ecooling.biz)
RE: Looking for high power TTV for TIM testing...
I will definitely look into the Intel DUO core chips. So far, AMD's Athlon 64 FX 57 was the highest power chip that I could find, but maybe with the accuracy of that new Intel chip, I could see variations between TIM's even at lower powers.
RE: Looking for high power TTV for TIM testing...
RE: Looking for high power TTV for TIM testing...
RE: Looking for high power TTV for TIM testing...
Downsides of the AMD chips: thermal diode not necessarily placed directly over hottest part of chip.
In addition, for this idea to work, I have to be able to get the die surface completely clean so I can send them to be metallized with Ti-Ni-Au.
RE: Looking for high power TTV for TIM testing...
Maximizing power is not that important as long as you can get a good dT measurement. Thermal resistance (C/W) and impedance (C-in2/W) should be independant of power.
ko (www.ecooling.biz)
RE: Looking for high power TTV for TIM testing...
ko (www.ecooling.biz)
RE: Looking for high power TTV for TIM testing...
I'll look into the flexible heaters. One idea we had was to use ceramics, but that is too expensive because we have to fabricate, calibrate, and throw them away every time.
RE: Looking for high power TTV for TIM testing...
Keith Cress
Flamin Systems, Inc.- http://www.flaminsystems.com