Exceeding maximum absolute voltage

  • Thread starter Thread starter larry moe 'n curly
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larry moe 'n curly

By how much can the maximum absolute voltage of 2.3V for DDR2 DRAM
chips be exceeded? I don't intend to do it, but I have a motherboard
that lets the memoy voltage be set as high as 2.839V, and it's maker
says that's OK, although they won't guarantee against damage.
 
larry said:
By how much can the maximum absolute voltage of 2.3V for DDR2 DRAM
chips be exceeded? I don't intend to do it, but I have a motherboard
that lets the memoy voltage be set as high as 2.839V, and it's maker
says that's OK, although they won't guarantee against damage.
Click to expand...

One way to get that info, is if the manufacturer writes up an
ISSCC (International Solid State Circuits Conference) paper.
Sometimes, if they've done a new semiconductor process, the
details will be given in the paper, including the "real"
absolute max (i.e. the value that killed the device in the lab,
something akin to breakdown voltage). The only time I read and
compared such a value using a paper like that, it was
about 200mV above the datasheet value, which isn't much margin
at all (and that was for a non-Intel processor).

Or, you can look in an enthusiast forum, and see what they're up
to. Some Micron D9 tested at 2.51V. Try to find a thread
where they burned some up :-)

http://www.xtremesystems.org/forums/showthread.php?t=121284

Paul
 
One way to get that info, is if the manufacturer writes up an
ISSCC (International Solid State Circuits Conference) paper.
Sometimes, if they've done a new semiconductor process, the
details will be given in the paper, including the "real"
absolute max (i.e. the value that killed the device in the lab,
something akin to breakdown voltage). The only time I read and
compared such a value using a paper like that, it was
about 200mV above the datasheet value, which isn't much margin
at all (and that was for a non-Intel processor).

Or, you can look in an enthusiast forum, and see what they're up
to. Some Micron D9 tested at 2.51V. Try to find a thread
where they burned some up :-)

http://www.xtremesystems.org/forums/showthread.php?t=121284

    Paul
Click to expand...

The fine geometry MOS these days is nearly like eeprom of the dark
ages. There is a threshold shift of the fets as they are clocked. My
recollection is threshold voltages get larger over time, but don't
quote me. The shift is incorporated into the spice models (or should
be). [If the threshold increases, then the weak model.] If you
increase the voltage, you probably won't get the 10 year life for
which the process is probably specd.

Stick with Asus or Gigabyte. I'm leery of 2nd tier mobos.
 
By how much can the maximum absolute voltage of 2.3V for DDR2 DRAM
chips be exceeded? I don't intend to do it, but I have a motherboard
that lets the memoy voltage be set as high as 2.839V, and it's maker
says that's OK, although they won't guarantee against damage.
Click to expand...


If they won't guarantee it, then they know it is too high. The numbers
you cite are almost 20% higher than spec.
 
By how much can the maximum absolute voltage of 2.3V for DDR2 DRAM ^^^^^^^^^^^^^^^^
chips be exceeded? I don't intend to do it, but I have a motherboard
that lets the memoy voltage be set as high as 2.839V, and it's maker
says that's OK, although they won't guarantee against damage.
Click to expand...
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

Read your own question again, with emphasis as shown.

In other words, pretty much zero, if you want it to operate as
advertised.

Good Luck!
Rich
 
By how much can the maximum absolute voltage of 2.3V for DDR2 DRAM
chips be exceeded?  I don't intend to do it, but I have a motherboard
that lets the memoy voltage be set as high as 2.839V, and it's maker
says that's OK, although they won't guarantee against damage.
Click to expand...

The world may never know:

 
Rich said:
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

Read your own question again, with emphasis as shown.

In other words, pretty much zero, if you want it to operate as
advertised.
Click to expand...

The motherboard manufacturer, BioStar, wouldn't guarantee against
damage even if I never exceeded the chip maker's maximum absolute of
2.3V, nor would they guarantee that the voltage applied to the memory
would never go above that by itself, such as because of a glitch.
 
larry moe 'n curly said:
By how much can the maximum absolute voltage of 2.3V for DDR2 DRAM
chips be exceeded? I don't intend to do it, but I have a motherboard
that lets the memoy voltage be set as high as 2.839V, and it's maker
says that's OK, although they won't guarantee against damage.
Click to expand...

By as much as you want!

For the most part though, voltage is directly related to temperature.
(simply ohms law) Increasing the voltage generally increases the core
temperature. The life expectancy decreases exponentially in many devices as
the voltage is increased past it's absolute maximums. The maximums also tend
to be "ideal"(hence the usage of absolute). Because of variations of
manufacturing, usage, etc, the maximums are a statistical result. Your usage
may vary.
 
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