I would say do the extraction with the 50 Ohm load and put the datasheet timing load into the model in the Rref, Cref, Vref section. Tom Dagostino Teraspeed(R) Labs 13610 SW Harness Lane Beaverton, OR 97008 503-430-1065 tom@teraspeed.com www.teraspeed.com Teraspeed Consulting Group LLC 121 North River Drive Narragansett, RI 02882 401-284-1827 -----Original Message----- From: owner-ibis-users@server.eda.org [mailto:owner-ibis-users@server.eda.org] On Behalf Of NG,MEI-YEE Sent: Monday, December 04, 2006 5:28 PM To: ibis-users@server.eda.org; ibis-users@server.eda.org Subject: [IBIS-Users] IBIS load Hi experts, According to the cookbook, when extracting V-T data, it is recommended to use a load circuit of 1R + 1F into manufacturer's suggested pullup resistor termination and voltage. However, when I use the suggested pullup resistor (1.5K), the rising waveform takes up to 100ns to stabilize, but the falling waveform requires less than 10ns. This creates inaccuracy due to the resolution of the points (when I use 100ns simulation time). In the IBIS model, I also included a waveform for 50Ohm pullup resistor (as recommended by cookbook). The rising waveform for this is also within 10ns. I wonder if I can generate IBIS model with ONLY 50 Ohm pullup because the resolution is more appropriate in this case? I have verified this model and the simulation shows acceptable waveforms. Kindly advice whether it is a MUST to have a 1.5K pullup resistor V-T table. Thank you. Best regards, Mei Yee Ng IC Design Engineer Illumination and Color Management Solid-state Illumination Division Avago Technologies Malaysia Tel no: +604-6108515 -------------------------------------------------------------------- |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 Mon Dec 4 19:38:43 2006
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