Vinayak wrote: > We have this case where in the *buffer has feedback* and with R-load we see > V-T table with lot of ringing(oscillations) when pad has reached steady > state. > As this is no real situation for us as TL delay that buffer would see in > real world is too small > comparable to buffer tr/tf. I think you are saying that you get these oscillations in your simulations with the SPICE model that you used to create your IBIS model; and that you see them only in simulations, not real devices. If that is correct, then I'd investigate why the oscillations happen, and fix it. It isn't just because your buffer has feedback, because real devices also have feedback and they don't oscillate. SPICE is known to occasionally have numeric oscillations when it should be steady-state, which can be fixed by changing to Method=Gear. Oscillations can also happen because things are missing in the SPICE simulation, device models are too ideal and lack resistance, etc. If, on the other hand, your buffer really does oscillate when loaded this way, then you've got a different problem. One fix (not necessarily good) would be to truncate the V/T data just before the oscillations start, and/or smooth out the tail so it approaches the correct final value. Regards, Andy ----------------------------------------------------------------- |For help or to subscribe/unsubscribe, email majordomo@eda.org |with the appropriate command message(s) in the body: | | help | subscribe ibis <optional e-mail address, if different> | subscribe ibis-users <optional e-mail address, if different> | unsubscribe ibis <optional e-mail address, if different> | unsubscribe ibis-users <optional e-mail address, if different> | |or email a request to ibis-request@eda.org. | |IBIS reflector archives exist under: | | http://www.eda.org/pub/ibis/email_archive/ Recent | http://www.eda.org/pub/ibis/users_archive/ Recent | http://www.eda.org/pub/ibis/email/ E-mail since 1993Received on Wed Jan 4 08:49:31 2006
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