On Tue, 25 Mar 2008 09:07:54 -0700 (PDT), Adam Ierymenko
<adam.ierymenko@[EMAIL PROTECTED]
> put finger to keyboard and composed:
>Hey guys...
>
>I'm looking for a deep technical answer on this question from someone
>who knows something about chip design or at least chip quality
>control, technical specs, etc.
>
>I'm curious about whether undervolting can actually damage a chip. I
>know it could make it unstable, but could it actually damage the chip
>or shorten its life span (or the life span of other components)? Is
>this something to be concerned about or is it something like "yeah, it
>might shorten the theoretical life span from 100 years to 50 years"?
>
>The reason I'm asking is this comment:
>
>"Depending on the voltage your adjusting you could fry the chip by
>under-volting. Most chips these days require a few different voltages
>to run, and if you lower one, there are sometimes sneak paths where
>the logic that is not getting enough power can draw power from the I/O
>voltage, or other auxiliary voltages on the chip which can burn out IO
>and other parts since they were never designed to carry the amount of
>current drawn through the sneak path. There are usually some
>protections in place to prevent the burn out, but with millions of
>transistors on a chip it's sometimes hard to catch all of the possible
>sneak paths."
>
>Here's the context of the comment:
>
>http://forums.macrumors.com/showthread.php?p=5213018
>
>Is this really a potential issue that one would face in the normal
>life span of a computer? I would think that undervolting (keep in mind
>no overclocking here) would be much safer than overvolting/
>overclocking where I have heard fry stories. :)
>
>-Adam
I know that in the early days of DRAMs and EPROMs, there were devices
(eg 4116 16Kx1 DRAM) which required three supply rails, +5V, -5V, and
+12V. For these chips, the -5V rail had to be applied before and
removed after the other supply voltages.
- Franc Zabkar
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