Todd, Thanks for your inputs. I have verified the programming options of driver and it's fine. Here, I am attaching the correlation waveforms of the simulations by using a 0.1 ohm resistor instead of transmission line in both load (5pF & 30pF) cases. Still, I am seeing a bad correlation in 30pF case. Please ignore my previously attached *.PDF. Once again thanks for your response. Best Reagrds, Venu -----Original Message----- From: Todd Westerhoff (twesterh) [mailto:twesterh@cisco.com] Sent: Tuesday, December 13, 2005 5:43 PM To: Ummalaneni, Venu Babu (Venu); ibis-users@eda.org; ibis@eda.org Subject: RE: [IBIS-Users] hspice vs IBIS model correlation at different capacitive loads Venu, How long is the transmission line you're using ... about 1ns? Your IBIS driver in the 30pf case seems to be taking several round-trips to charge the load where the HSpice driver doesn't - if this is a programmable driver, is it possible the driver settings for the two plots are different? In the top plot for the 30pf case, the IBIS driver looks like a much weaker output with a faster slew rate to me ... Todd. Todd Westerhoff High Speed Design Group Manager Cisco Systems 1414 Massachusetts Ave Boxboro, MA 01719 email:twesterh@cisco.com ph: 978-936-2149 ____________________________________________ "Always do right. This will gratify some people and astonish the rest." - Mark Twain _____ From: owner-ibis-users@eda.org [mailto:owner-ibis-users@eda.org] On Behalf Of Ummalaneni, Venu Babu (Venu) Sent: Tuesday, December 13, 2005 5:38 AM To: ibis-users@eda.org; ibis@eda.org Subject: [IBIS-Users] hspice vs IBIS model correlation at different capacitive loads Hi Gurus, I have an ATA* IBIS model and it is correlating well with hspice model when I am using a 5pF load followed by a transmission line. If I replace the 5pF load with 30pF correlation is bad (particularly in 2nd page waveform of attached PDF). Could some one comment on this, where it is going wrong? Your comments/inputs are highly appreciated. Attachments: ata4nik_5pf.pdf - hspice and IBIS model waveforms captured using 5pF load ata4nik_30pf.pdf - hspice and IBIS model waveforms captured using 30pF load Thanks & Best Regards, Venu <<ata4n1k_30pf.pdf>> <<ata4n1k_5pf.pdf>> ----------------------------------------------------------------- |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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