Hi Robert, A vref for the input buffers may be essential. The duty cycle variation for the output of the input buffer may be too great to run at greater than 100Mhz clock frequency. There are also duty cycle variations for the clock driver that are quite stringent. I asume that your bus width is wide enough to require more than one memory chip. If you are able to use only one memory chip, the skew between the dqs and the data may be intolerable for the ASIC controller. Thanks Jim Freeman Robert Lindsell wrote: > Hello si-listers, > > Does anyone know if it's possible to use 2.5V LVTTL/LVCMOS buffers with > a planar, point-to-point implementation of DDR (ie. no DIMMs, just one > DDR chip and an ASIC controller) > > Our ASIC library vendor wants $50k for SSTL-2 buffers, which seems a bit > extreme... but maybe it isn't???? > > Any info and opinions welcome. > > Regards, > > Robert > > -- > Robert Lindsell, Principal Hardware Engineer > Canon Information Systems Research Australia > PO Box 313 NORTH RYDE NSW 2113 > mailto:robert.lindsell@xxxxxxxxxxxxxxxxxx > Fax: +61-2-9805-2929 Phone: +61-2-9805-2876 > > ------------------------------------------------------------------ > To unsubscribe from si-list: > si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field > > or to administer your membership from a web page, go to: > //www.freelists.org/webpage/si-list > > For help: > si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field > > List archives are viewable at: > //www.freelists.org/archives/si-list > or at our remote archives: > http://groups.yahoo.com/group/si-list/messages > Old (prior to June 6, 2001) list archives are viewable at: > http://www.qsl.net/wb6tpu > ------------------------------------------------------------------ To unsubscribe from si-list: si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field or to administer your membership from a web page, go to: //www.freelists.org/webpage/si-list For help: si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field List archives are viewable at: //www.freelists.org/archives/si-list or at our remote archives: http://groups.yahoo.com/group/si-list/messages Old (prior to June 6, 2001) list archives are viewable at: http://www.qsl.net/wb6tpu