Subject: AW: [IBIS-Users] I-V vs V-T curves
From: Lenski Eckhard (Eckhard.Lenski@icn.siemens.de)
Date: Sun Apr 21 2002 - 22:54:12 PDT
Hello Tim,
I assume that you are modeling an LVDS-output.
Normaly ( cmos ) you compare the crossing of the 50Ohmload curves with the pullup - pulldown curves
- 50 Ohm to Gnd crossing with pullup curve
- 50 Ohm to Vcc crossing with pulldown curve
and the rising falling waveforms are measured with a 50 Ohm load to GND and to VCC.
For LVDS you have to look for the crossing of your 50 Ohm to 1.2V load-curve with the pullup and pulldown curves
( so you havve to use the same loadcurve twice )
and then there should be no ( or no significant ) mismatch.
By the way, I think the ibis-checker is always using 50 ohm to gnd and 50 Ohm to vcc.
If you have further questions, please let me know.
regards
Eckhard Lenski
Eckhard Lenski
Siemens AG
ICN WN OP TDC TC3
81359 München
Tel: 0049 89 722 27776
Fax: 0049 89 722 44692
Email: eckhard.lenski@icn.siemens.de
-----Ursprüngliche Nachricht-----
Von: Timothy Coyle [mailto:Timothy.Coyle@nsc.com]
Gesendet: Freitag, 19. April 2002 20:24
An: ibis-users@eda.org
Betreff: [IBIS-Users] I-V vs V-T curves
Hi,
I am trying to determine where my mismatch end points are coming from in an IBIS file I am creating. How do I get the end points from the pullup and pulldown I-V data
so I can compare them to the endpoints in my V-T curves? (load condition for V-T data is 50 ohms to 1.2V with endpoints 1.0V and 1.4V)
Thanks,
Tim
|------------------------------------------------------------------
|For help or to subscribe/unsubscribe, email majordomo@eda.org
|with just 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 written 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
This archive was generated by hypermail 2b28 : Sun Apr 21 2002 - 23:23:47 PDT