RE: [IBIS-Users] logic0 and logic1 problem in IBIS models

The same principle applies to differential buffers as to single ended.  A
load line constructed between the two IV curves should predict the output
high and low levels.  In this case the magnitudes of the currents will be
the same but the polarity will be reversed.  The pullup will have -X mA and
the pulldown will have +X mA.  The out put voltages will be the voltage at
(-)X mA.

Tom Dagostino
Teraspeed Labs
13610 SW Harness Lane
Beaverton, OR 97008
503-430-1065
http://www.teraspeed.com
tom@teraspeed.com

Teraspeed Consulting Group LLC
121 North River Drive
Narragansett, RI 02882
401-284-1827

Teraspeed is the registered service mark of
Teraspeed Consulting Group LLC

-----Original Message-----
From: Akhilesh CHANDRA [mailto:akhilesh.chandra@st.com]
Sent: Monday, April 11, 2005 10:05 AM
To: tom@teraspeed.com
Cc: ibis-users@eda.org; Akhilesh CHANDRA
Subject: Re: [IBIS-Users] logic0 and logic1 problem in IBIS models


Hello Tom,

Yes, I agree with you but I find out most of the simulator not follow
this rule for differential cells and fails to give correct logic labels.
Is any other way by which it calculate for differential cells.

Regards
Akhilesh

Tom Dagostino wrote:

>Akhilesh
>
>The logic 1 and logic 0 states depend on the load attached to the buffer.
>If the load is an open circuit then the logic 0 will be the voltage in the
>pulldown table where the current is zero.  The 1 will be the voltage in the
>pullup table where the current is zero.  You can construct load lines and
>apply those to the IV tables to predict the output voltage for any load.
>
>Regards,
>
>Tom Dagostino
>Teraspeed Labs
>13610 SW Harness Lane
>Beaverton, OR 97008
>503-430-1065
>http://www.teraspeed.com
>tom@teraspeed.com
>
>Teraspeed Consulting Group LLC
>121 North River Drive
>Narragansett, RI 02882
>401-284-1827
>
>Teraspeed is the registered service mark of
>Teraspeed Consulting Group LLC
>
>-----Original Message-----
>From: owner-ibis-users@eda.org [mailto:owner-ibis-users@eda.org]On
>Behalf Of Akhilesh CHANDRA
>Sent: Monday, April 11, 2005 8:09 AM
>To: ibis-users@eda.org
>Cc: Akhilesh CHANDRA
>Subject: [IBIS-Users] logic0 and logic1 problem in IBIS models
>
>
>
>Hello ,
>
>  I am working on one of my differential cells. When I validate my IBIS
>models from two different simulator then I got two different logic 0 and
>logic1 values. To find out it's problem of simulator or my models I must
>know what are the logic0 and logic1 according to the models. Can any one
>have any idea how we can extract logic0 and logic1 from the model files.
>
>  I am highly blocked due to this issue. Your help is deeply appreciated.
>
>Regards
>Akhilesh
>
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