Is it possible for Programmable IC's (PIC) to work beyond their Operating Temperature?

Question

I am currently part of a Research and development Engineering Team (which I am newbie) and we are trying to find a solution on how to extend the normal operating temperature of the chip. The IC that we are using is dsPIC33FJ128MC706 of Microchip which its highest operating temperature is 150°C. We somehow aim to let the chip work at a temperature of 180°C. Is this possible or is it just wishful thinking?

Answer 1

If you want the chip to operate in ambient temperature of 150'C then you will need some form of active cooling for the chip. If you are looking at increasing operating temperature of the actual chip, I imagine that is quite difficult and there is probably a lot research going into this topic from various manufacturers.

However with the question you pose, I believe you are referring to storage temperatures of 150'C. There may be a little misunderstanding. The operating temperatures are much lower which make your problem worse.

With a quick look at the datasheet. Absolute Maximum Ratings(1)

Ambient temperature under bias ............................ -40°C to +85°C

Storage temperature ............................ -65°C to +150°C

http://ww1.microchip.com/downloads/en/DeviceDoc/70287C.pdf pg 275

Answer 2

The maximum operating temperature has two principal limitations. One is whether the design will work, considering that bias currents increase and base voltages shift. The second is how long the chip will survive against the various degradation processes that are enabled or accelerated by high temperatures.

The first is quite easy to check. Increase the temperature of the device and see when it stops working.

The second has to be estimated. All silicon processes are broadly similar in that their wear-out is accelerated by temperature. The factors for different processes might be slightly different, however the general trend is the same. There is an exponential decrease in life with incresaing temperature.

Take this paper for instance from TI. They say that for a particular device, operating at 125C rather than 105C results in a 5-fold reduction in lifetime.

If the same factor applied to your device, over the temperature range, 85C max specified temperature to 180C target temperature, then the lifetime reduction would be in the order of 625-fold. However, I suspect the factor increases at higher temperatures, as we activate different mechanisms like diffusion.

Answer 3

Some applications require high temperatures, so manufacturers usually have one or two chips that will fit your needs, for example this one works till 210°C:

http://www.ti.com/product/sm320f28335-ht

Microchip probably has some too. Of course, you'll need special solder, ceramic boards and other exotic unobtainium stuff, so the $300 price tag on the chip should be just a drop in the bucket in the end...

TL/DR: Unless you're making something really exotic like a borehole sensor for oil drilling, there are probably other, cheaper, better solutions.

Answer 4

The IC that we are using is dsPIC33FJ128MC706 of Microchip which its highest operating temperature is 150°C.

chips working at that kind of temperature are very rare and i'm sure quite expensive. you may want to re-read the datasheet to be (super) sure.

We somehow aim to let the chip work at a temperature of 180°C. Is this possible or is it just wishful thinking?

you can answer Microchip; or you can simply test. I would be surprised if it didn't work if the chip was indeed specified for 150c working temperature.

Otherwise, it would be quite difficult to make most chips work at that kind of temperature.

A more realistic solution is to provide better cooling.