The short answer is ..... You can safely run it down to ZERO decgrees
centigrade.

Some standard grade chips will work below zero, some won't. There is no
guarantee how much lower *all* chips will run at. It's similar to the
overclocking debates. Some chips will run with faster crystals, some won't.

Since this is a comercial device, you were given (or proposed them yourself
for someone to approve). Get the chip that meets the specs.

Now, having said that, I've run a standard grade 16C711 chip to almost -40
centigrade, at which point it stopped working. This was the only chip that
made it that far. Another micro made it to -20. These were '711 devices made
by an outside design firm that doesn't know how to read a spec sheet: the
product was required to work +60/-20 centigrade. Why they used standard
temperature chips is beyond me. Lots of stuff started deviating (op-amp and
pressure sensor) or malfunctioning (micro and serial interface) around -15
to -20; it was hard to tell if it was the micro or other components. The
exercise of finding out really wasn't worth anyone's time.

Bottom line is that specs exist for a reason. If your product fails because
you exceeded the mfg. specs, you have only yourself to blame :)

Oh, and let me get this off my chest as well -> ignore all the specs on a
datasheet marked 'typical'. That's useless marketing information. Ok, now i
feel better :)

Anyone have differing experiences they'd like to share?

--
Phil Eisermann


> -----Original Message-----
> From: Gary [mailto:questuk1@HOTMAIL.COM]
> Sent: Tuesday, March 19, 2002 2:19 PM
> To: PICLIST@MITVMA.MIT.EDU
> Subject: [PIC]: Can standard 16F628 operate below 0 centigrade?
>
>
> Hi,
>
> PIC16F628-04/P running at 4Mhz @ 3V
>
>
> I have designed a project using the PIC16F628-04/P, microchip
> states that the operating temperature is 0c to +70c, how low
> have you run this chip at successfully.
>
> I realise you can get different versions for lower
> temperatures, but I am interested how close you have to be to
> the tolerance in the book?
>
> This is going into a commercial device, so I assume we may
> well have to go for the 'lower temperature version' ?
>
> Any idea on the difference in price between PIC16F628-04/P,
> PIC16F628-04I/P, PIC16F628-04E/P versions.
>
>
> Thanks Gary
>
> --
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>

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