vco7c thermal results

[Martin Czech]

> Now, talking about spray freezing... a very dear friend of mine got
> the experience that instead of "discovering" errors by spray-freezing
> components (like possibly wacko EPROMs) he actually introduces new
> errors. So, excess use for the spray can may be a good way to actually
SNIPPED

We used freeze spray all day, to detect timing faults.
The No. 1 problem is condensed water, or ice, which will lead
to leakage or even temporarily disfunction, until the part
has dryed again.
Now we have a thermo stream with dryed air.

I never had problems with thermal/mechanical stress on chips,
but there is certainly a socket problem if you heat up the
thermostream from -40C to 120C, which takes about 30 seconds.

Our chips/packages are tested for thermal/mechanical stress imunity,
via temperature shock/pressure coocker. If you use the right plastic
material, this stress is not harmfull. 

But if your chip has a very odd aspect ratio and you use the wrong 
package plastic you'll shure crack the chip, that's certainly true.

m.c.