Subject: RE: [IBIS-Users] CAN 3.3v IBIS models can be used for 5v device
From: Tom Dagostino (tom@teraspeed.com)
Date: Mon Feb 03 2003 - 21:16:29 PST
Sudheer
When you increase the voltage on a logic gate you are changing the bias on
the FETs (I'm assuming a CMOS technology, the same applies for bipolar).
With the increased Vgs, from 3.3 to 5.0, you are turning on the FET harder
resulting in a lower output impedance. You are also speeding the device up.
So the 3.3 Volt model will be slower and have higher output impedance than
the 5 Volt version. Also the voltage swing of the transitions will be
greater with 5 Volt operation.
The differences in C_comp will pale compare to the ones mentioned above.
Not a good idea.
Tom Dagostino
Teraspeed Consulting Group LLC Teraspeed Consulting Group LLC
2926 SE Yamhill St. Device Modeling Division
Portland, OR 97214 13610 SW Harness Lane
Beaverton, OR 97008
http://www.teraspeed.com 503-430-1065
tom@teraspeed.com
-----Original Message-----
From: owner-ibis-users@server.eda.org
[mailto:owner-ibis-users@server.eda.org]On Behalf Of Sudheer B S
Sent: Monday, February 03, 2003 1:02 PM
To: ibis-users@server.eda.org
Subject: [IBIS-Users] CAN 3.3v IBIS models can be used for 5v device
Hi All
I have IBIS model for a device operating at 3.3v , The model of
the same device for 5V is not
availible .My quection is , Since the technology remains same by
extending the Pull up .pulldn
pwrclamp and Gnd clamp Curves AND by Changing the Voltage range
(also threshold) Can we make IBIS models ??
Does the change in device voltage will have Large Variation in C_comp
??
Instead of Going for Equivalent 5v device , this should be the better
choice .
please Correct me If I my approach is Wrong
Thank you
SUDHEER
|------------------------------------------------------------------
|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
|------------------------------------------------------------------
|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 : Mon Feb 03 2003 - 21:23:06 PST