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Old 10-24-2007, 02:27 AM
David Spencer
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Default Re: Changing refresh rate for DRAM while in operation?


<[email protected]> wrote in message
news:[email protected]..
>
> Although it's not expressed in DRAM specs and you wouldn't want to
> rely on it, the effect of reducing refresh rate is to increase the
> access time. I'm not up-to-date with DRAM technology, but my
> experience with devices 30 years ago was that you could turn off
> refresh (and all other access) for 10s or more without losing the
> contents, provided you weren't pushing the device to its access time
> limits.
>
> So, it's not impossible that reducing refresh rate would have a use
> (albeit outside the published device spec). But, as you suggest, it
> would help if he would just tell us what he's trying to do.
>
> Mike


Although that may well be the case for asynchronous DRAMs (because the
reduced charge in the memory cell capacitor would mean that the sense
amplifier took longer to register the state), this would not be the case for
SDRAM since this registers the outputs a fixed number of clocks after the
access starts. If the underlying access time increased by too much then the
data would just be wrong.


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