Subject: RE: [IBIS] IV curve question...
From: Robert Haller (rhaller@sisoft.com)
Date: Sat Nov 02 2002 - 11:13:02 PST
Matt,
What I like to do is run the IBIS model through SPICE and generate IV
curves. I then Overlay the .ibs IV curves with the SPICE IV curves. I
can see exactly how my simulator (HSPICE) is interpreting the .ibs file.
We have a tool named SiAuditor which not only helps perform this function
it also fully integrates rigorous wavform processing, Static timing with
HSPICE.
For more information please visit our website www.sisoft.com
regards,
bob
-- Robert Haller (rhaller@sisoft.com) Signal Integrity Software Inc. 6 Clock Tower Place, Suite 250 Maynard, MA 01754 Phone: (978) 461-0449, ext 15> Ben, Tony: > > Hi. I'm using Specctraquest. > > The extraction process has left an "exaggerated" pwr_clamp and a > weaker, > non-monotonic pulldown and pullup. When I translate the non-montonic > pulldown & pullup curves from Ibis to DML, the tranlator see's the > non-monotonic curve and does me a favor and flattens it out. Then, when > you add the exaggerated clamps (due to extraction) into the overall > curve during simulation, the clamping is stronger than it should be (by > the difference between the "real" bent curve, and the flattened DML > curve). > > The difference (in this case) can be 15 mA of extra clamping. It > probably > won't hurt in the pulldown case since the inaccuracy is in the pwr_clamp > (tough to see that part of the curve being used when pulling low). But > it will hurt in the pullup case and in the high clamp of the receiver. > > So, the simulator does it automagically, but it isn't the most accurate > representation. I just wanted to see the curves summed up BEFORE SQ > "fixed" them to see the true curves. They actually look reasonable, but > won't be used in the simulator that way. > > Regards, > > Matt > > > > -----Original Message----- > From: Silva, Benjamin P [mailto:benjamin.p.silva@intel.com] > Sent: Friday, November 01, 2002 2:24 PM > To: ruston, matt; Ingraham, Andrew > Cc: ibis@eda.org > Subject: RE: [IBIS] IV curve question... > > > The simulator should do that automagically. > > Ben > >> -----Original Message----- >> From: ruston, matt [mailto:ruston_matt@emc.com] >> Sent: Friday, November 01, 2002 11:33 AM >> To: 'Ingraham, Andrew'; ruston, matt >> Cc: ibis@eda.org >> Subject: RE: [IBIS] IV curve question... >> >> >> Andy: >> >> Hi. The non-monotonicity is attributable to the separation >> of the various >> clamp and pulldown curves. I added the clamp curves back in >> (in Excel) and >> the curves looked normal. >> >> Does anyone know of an easier way to combine these clamp >> currents back with >> the pullup and pulldown curves? Any freeware utilities? >> >> Regards, >> >> Matt >> >> -----Original Message----- >> From: Ingraham, Andrew [mailto:Andrew.Ingraham@hp.com] >> Sent: Thursday, October 31, 2002 2:14 PM >> To: ruston, matt >> Cc: ibis@eda.org >> Subject: RE: [IBIS] IV curve question... >> >> >> Matt, >> >> I didn't know that the supply voltage was only 1.8V. Since in >> your sketch the non-monotonic region begins around there, it >> is possible that the non-monotonicity is related to the >> separation of currents into pull-down and clamp I-V tables. >> >> The spikeyness almost sounds like a simulator bug, especially >> with the way you can affect the spike by changing Tstep. >> >> 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 1993 >> > ----------------------------------------------------------------- > |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 1993
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