Subject: Usefulness of Cref, Rref and Vref

From: "Shripadaraj Devrao" <[email-masked]>
Date: Tue, 27 Oct 1998 03:29:13 PST

Hi IBIS gurus,

What is the significance of model subparameters Cref, Ref and
Vref? Are they being used in simulation to get V-T data OR these
parameters are just passed as it is to imulator?

Why propogation delay is not included as one of the parameters,
along with these delay measurement test loads?

Thanks

Raj

______________________________________________________
Get Your Private, Free Email at http://www.hotmail.com

---

From: Stephen Peters <[email-masked]>
Date: Tue, 27 Oct 1998 09:29:47 -0800

> along with these delay measurement test loads?

Hello Raj:

     The Cref, Ref and Vref parameters are the load under which
the devices Tco (clock to output) or Tpd (in to output) propagation delay
is measured.  In general these parameters are passed thru to the simulator
so that the simulator can calculate the difference in "time to Vmeas" 
between the test load and the actual load.  This number is then used in
figuring the flight time of an interconnect.

The actual propagation delay is not included because it does not effect
the actual SI simulation waveforms or interconnect timing.

           Regards,
           Stephen Peters
           Intel Corp.