[SI-LIST] Re: DDR-II: SSTL_18 & ODT

Thanks for the response -- very useful and I got a good chuckle to boot!  BTW, 
can you tell me (without having to kill me) when all of this DDR-II info is 
supposed to become public?  I heard Sept -- I'm hoping it's Sept 1.

Thanks,
-Bret


Quoting "D. C. Sessions" <dcs@xxxxxxxxxxxxxxxx>:

> 
> On Mon, 2002-08-12 at 11:35, Bret Stott wrote:
> 
> > I am a new member of this list and I have a few questions about DDR-II that
> I 
> > was hoping someone could help me out with.  Currently, I don't have access
> to 
> > JEDEC so most of my information is from alternate sources such as the
> Samsung 
> > DDR-II spec.
> > 
> > o Can anyone point me at a SSTL_18 specification?
> 
> Yes, but then I'd have to kill you.
> 
> Seriously, this should be hitting publication Very Soon Now.
> We just recently gave the JEDEC office the go-ahead.  Look
> for JESD8-15.
> 
> > o Can someone help me understand the on-die-termination strategy for
> DDR-II?  
> > Why are the values 75 & 150 Ohms?  What electrical topology is being
> assumed?
> 
> Your basic DDR DRAM topology, w/o the motherboard shunt resistors.
> ODT is still somewhat controversial, which is why there are
> provisions to disable it altogether.
> 
> > o My initial analysis suggests that it is possible to use class I drivers
> for 
> > the address bus (5 load) and also for a point-to-point data bus.  The data
> bus 
> > may require some non-standard termination values though.  Does anyone have
> any 
> > information that supports of refutes this?
> 
> There Is No Class One.  SSTL-18 ditches the "Class I" driver
> spec since the SSTL-2 class I spec has caused a lot of
> confusion and we couldn't find any valid uses for it.
> 
> (Yeah, I know that that last if flame bait.  If you don't like
> the JC-16 tendency to concentrate on DRAM to the exclusion of
> other applications, JOIN THE FREAKING COMMITTEE!)
> 
> -- 
> | May I have the serenity to accept the things I cannot change, |
> |  the strength to change the things I cannot accept, and the   |
> |    cunning to hide the bodies of those who got in my way.     |
> +------------- D. C. Sessions <dcs@xxxxxxxxxxxxxxxx> -----------+
> 
> 
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----------------------------------------------------------------
Bret Stott                      phone: (408) 772-5028
Syano Designs                   fax:   (408) 243-1850
771 Hilmar Street               email: bstott@xxxxxxxxxxxxxxxx
Santa Clara, CA 95050           http://www.syanodesigns.com
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