Hi Lars, In the past I have seen this type of oscillation at the end of the IV curve usually resulting from a) improper tool extraction method for clamp and pulldown/pullup IV curves b) improper loading in IV data extraction c) actual circuit SPICE issues. I would look at the raw pulldown/pullup IV curves before anything is extracted to make sure it's not an extraction calculation issue. You could also try using a different IV data extraction (DC vs Transient AC) as sometimes this can give you a slightly different result due to setup conditions in SPICE model. Finally you may want to adjust some of your HSPICE .option settings to make sure you are not getting any convergence issues or other HSPICE runtime issues that may affect your results. You could also manually edit the end of the IV curves to be smoothed out (some tools let you do this interactively) but I would only do this if you can do full correlation to verify it won't affect simulation performance and accuracy. Best, Timothy Coyle President Signal Consulting Group LLC 405 Western Ave #430 South Portland, ME 04106 Tel: 617.297.2566 Email: tim.coyle@siconsultant.com Web: http://www.siconsultant.com SharkSim - Signal Integrity IBIS Modeling Software (www.sharksim.com) -----Original Message----- From: owner-ibis-users@server.eda.org [mailto:owner-ibis-users@server.eda.org] On Behalf Of Lars Snith Sent: Tuesday, December 15, 2009 3:46 AM To: ibis-users@server.eda.org Subject: [IBIS-Users] PullUp/PullDown toggle? Hello, In some of my models the pullup/pulldown curves end up by toggling +/- 10mA. It is not of much actual consequence, but estethically foul. An example follows below. I get the same result with s2ibis3 and one other independent tool (also using HSpice for simulation), so I suspect this is really in the HSpice result files. Has anyone seen something similar before? 2.40 -12.7710mA -7.5000mA -21.3261mA 2.46 -12.8090mA -8.0000mA -21.3770mA 2.52 -12.8400mA -7.0000mA -21.4280mA 2.58 -12.9000mA -7.0000mA -21.4810mA 2.64 -13.0000mA -7.0000mA -21.5310mA 2.70 -13.0000mA -8.0000mA -21.5800mA 2.76 -13.0000mA -8.0000mA -21.6300mA 2.82 -13.0000mA -10.0000mA -22.0000mA 2.88 -13.0000mA 0.0A -22.0000mA 2.94 -10.0000mA -10.0000mA -22.0000mA 3.00 -10.0000mA -10.0000mA -22.0000mA 3.06 -20.0000mA -10.0000mA -20.0000mA 3.12 -20.0000mA 0.0A -20.0000mA 3.18 -10.0000mA -10.0000mA -30.0000mA 3.24 -10.0000mA -10.0000mA -20.0000mA 3.30 -10.0000mA -10.0000mA -20.0000mA 3.36 -10.0000mA -10.0000mA -30.0000mA 3.42 -20.0000mA 0.0A -20.0000mA 3.48 -20.0000mA -10.0000mA -20.0000mA 3.54 -10.0000mA -10.0000mA -30.0000mA 3.60 -10.0000mA -10.0000mA -20.0000mA Best regards, Lars Snith -- Those who can, Do Those who can't, Simulate -- This message has been scanned for viruses and dangerous content by MailScanner, and is believed to be clean. -------------------------------------------------------------------- |For help or to subscribe/unsubscribe, e-mail majordomo@eda-stds.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 e-mail a request to ibis-request@eda-stds.org. | |IBIS reflector archives exist under: | | http://www.eda-stds.org/pub/ibis/email_archive/ Recent | http://www.eda-stds.org/pub/ibis/users_archive/ Recent | http://www.eda-stds.org/pub/ibis/email/ E-mail since 1993 -- This message has been scanned for viruses and dangerous content by MailScanner, and is believed to be clean. -------------------------------------------------------------------- |For help or to subscribe/unsubscribe, e-mail majordomo@eda-stds.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 e-mail a request to ibis-request@eda-stds.org. | |IBIS reflector archives exist under: | | http://www.eda-stds.org/pub/ibis/email_archive/ Recent | http://www.eda-stds.org/pub/ibis/users_archive/ Recent | http://www.eda-stds.org/pub/ibis/email/ E-mail since 1993Received on Tue Dec 15 07:58:01 2009
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