Dear Babid A, Regarding your enquiry on the input termination in the IBIS file, I would like to shed you some light on the input on chip termination information if it is embedded into the clamps of the IBIS model. Take the differential LVDS input with 100ohm on chip termination as example; you would be able to see in the ground clamp curve that there is a nearly linear region normally around the VCM. Assuming the curve is linear (with resistive load), and by performing normal R = dV/dI at the linear region (usually near Vcm), you would be able to get the R ~ 100 ohm. For the differential LVDS input without on chip termination, by performing the same steps, you would be getting the R in kOhm or MOhm which is the expected high impedance.. Examples: 1) LVDS input without OCT (gnd clamp) 9.8485e-01 -1.3747e-04 -8.6054e-05 -1.7763e-04 1.0606e+00 -9.8227e-05 -4.8802e-05 -1.3748e-04 1.1364e+00 -5.8938e-05 -1.1577e-05 -9.7341e-05 1.2121e+00 -1.9651e-05 2.5600e-05 -5.7176e-05 1.2879e+00 1.9611e-05 6.2702e-05 -1.7014e-05 1.3636e+00 5.8831e-05 9.9719e-05 2.3136e-05 1.4394e+00 9.7995e-05 1.3670e-04 6.3269e-05 1.5152e+00 1.3708e-04 1.7357e-04 1.0332e-04 1.5909e+00 1.7607e-04 2.1044e-04 1.4338e-04 1.6667e+00 2.1499e-04 2.4719e-04 1.8344e-04 R ~ (9.8485e-01 - 1.66670)/(-1.3747e-04 - 2.1499e-04) = 1.93kOhm 2) LVDS input with 100Ohm OCT (gnd clamp) 1.1364e+00 -1.1973e-03 -2.1547e-04 -2.0607e-03 1.2121e+00 -3.9894e-04 4.7429e-04 -1.2113e-03 1.2879e+00 3.9841e-04 1.1609e-03 -3.6063e-04 1.3636e+00 1.1933e-03 1.8447e-03 4.8961e-04 1.4394e+00 1.9837e-03 2.5246e-03 1.3382e-03 1.5152e+00 2.7695e-03 3.2008e-03 2.1837e-03 R~ (1.1364 - 1.5152)/(-1.1973e-03 - 2.7695e-03) = 95 Ohm Please feel free to let me know if you have any concern. Thank you. Best Regards, Chan, Chee Pin Component Applications Engineer Altera Corporation ________________________________ From: owner-ibis@eda.org [mailto:owner-ibis@eda.org] On Behalf Of Babid A Sent: Sunday, May 17, 2009 4:42 AM To: ibis-users@eda.org; ibis@eda.org Subject: [IBIS] termination on input buffer Hi, How to determine if the input is terminated from a IBIS file? What is the keyword that I should look for? -Thanks, -- This message has been scanned for viruses and dangerous content by MailScanner<http://www.mailscanner.info/>, and is believed to be clean. ________________________________ Confidentiality Notice. This message may contain information that is confidential or otherwise protected from disclosure. If you are not the intended recipient, you are hereby notified that any use, disclosure, dissemination, distribution, or copying of this message, or any attachments, is strictly prohibited. If you have received this message in error, please advise the sender by reply e-mail, and delete the message and any attachments. Thank you. -- 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 Sun May 17 19:26:37 2009
This archive was generated by hypermail 2.1.8 : Sun May 17 2009 - 19:28:07 PDT