Naren, > In my circuit there are two devices PCI-X 1.0a driver and receiver. > I have IBIS model for receiver. > I don't have IBIS model for driver. Don't forget, most PCI-X signals are bi-directional. If you have one device's models, it should be both a receiver and a driver. PCI-X buffers, like PCI buffers, are bounded by a specification, and one *should* not have a buffer whose I/V curves exceed those bounds. In theory, therefore, one could construct a generic PCI-X IBIS model or models that display the best- and worst-case characteristics in some manner. Then, in principle, one could use that model in simulations, in lieu of a real device model, and hope that your real PCI-X device is somewhere between the extremes displayed by the generic model. While this can be done, and it is better than doing nothing until you have a real model, I'd use the results with a lot of caution. Simulate, then apply liberal margins. Some devices do exceed the limits in the specs. Press your ASIC vendor for a real model. And I'd be especially cautious about using the models for some other PCI-X device as a "stand-in" for your device's model. (Still, however, it is better than nothing.) Is this a hard-wired or embedded bus with fixed devices on both ends? The more usual case is a bus with connector(s), allowing any device to be plugged in on the other end. In that case, one can't simulate the bus with every possible PCI or PCI-X card out there, so generic models are the only practical way to do it, along with a handful of simulations using some actual device models you have available. If your bus has a connector, don't forget that a PCI device can be plugged into it too, and PCI's range of drive strengths (V/I curves) is wider than PCI-X. Regards, Andy ------------------------------------------------------------------ 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 FAQ wiki page is located at: http://si-list.org/wiki/wiki.pl?Si-List_FAQ List technical documents are available at: http://www.si-list.org 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