Jinx wrote :

> > > My question is - if Mclr has already broken down, what's the
> > > point of protecting it ? 
> > 
> > A breakdown with minimal current (limited by the resistor) will
> > do no damage, an unlimited current (capacitor directly on the
> > /MCLR pin) possibly will.
> 
> Have I misinterpreted Microchip's term "breakdown" for "failure" ?

Yes, in a way.
They are two destinctive terms, when it comes to semiconductors.

> If not, exactly what do they mean by "breakdown" ?

It's not a question of how MC defines it, realy.

The term "breakdown" in semiconductiors, is when you
exceed the "breakdown voltage" of a semiconduction junktion
or a isolating layer (as the "metal oxide" layer in a CMOS device).
This cases current to flow in a non-designed way.

Now, if this will gave permanent failurs, depends on how much
current is allowed to "rush" due to this breakdown. If not to high,
the breakdown will self-heal when the current (and voltage) is
removed. If there isn't enything limiting the current, permanent
damage might be the result.

So MC adviced to put a resitor in series with MCLR so the
current rush from the capacitor would not cause permanant
damage in the case of a breakdown.

Well, that's how I understand it, anyway... :-)

Jan-Erik.
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