Chris,
thank you very much for you kindness.
I understand very well.
- Regards,
A.Takegama
************************************
* Name : Akihiro Takegama *
* E-mail : tkgm@tdc.tijp.ti.com *
* Corp. : Texas Instruments *
************************************
-----------------------------------------------------------------------
------- Start of forwarded message -------
Sender: crokusek@qdt.com
Date: Wed, 01 Apr 1998 09:21:51 -0800
From: Chris Rokusek <crokusek@qdt.com>
Organization: Quad Design Technology
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To: Akihiro Takegama <tkgm@mario.tdc.tijp.ti.com>
Cc: ibis-users@vhdl.org
Subject: Re: [Re: About WARNING of ibischk2]
References: <199804010915.SAA15589@mario.tdc.tijp.ti.com>
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Akihiro,
The "LOW" curve used in the DC vs. AC test is the sum of BOTH shunt
curves (POWER_Clamp/GND_Clamp) + the Pulldown Curve.
Similarly the "HIGH" curve used in the test is the sum of BOTH shunt
curves + Pullup Curve.
Chris
Akihiro Takegama wrote:
>
> Chris,
> thank you very much for your quick response and answer.
>
> I would like to confirm my issue.
>
> # Is it crosspoint 50 Ohm slope against the value of [Pulldown]
> + [Gndclamp] ?
>
>
> (I)
> | * [Pulldown] + [GNDclamp]
> 0.6A x ****
> | x **
> | x *
> | *
> | * ^ x
> | * | x slope = 50 Ohm
> | * | x
> *--------|-----------x---------
> 0.0V | 3.0 V (V)
> (0.95V)
> #####
>
> - Regards,
> A.Takegma
> > ************************************
> > * Name : Akihiro Takegama *
> > * E-mail : tkgm@tdc.tijp.ti.com *
> > * Corp. : Texas Instruments *
> > ************************************
>
> -----------------------------------------------------------------------
> ------- Start of forwarded message -------
> Sender: crokusek@qdt.com
> Date: Tue, 31 Mar 1998 10:01:46 -0800
> From: Chris Rokusek <crokusek@qdt.com>
> Organization: Quad Design Technology
> X-Mailer: Mozilla 3.01 (X11; I; SunOS 4.1.4 sun4m)
> Mime-Version: 1.0
> To: Akihiro Takegama <tkgm@mario.tdc.tijp.ti.com>
> Cc: ibis-users@vhdl.org
> Subject: Re: About WARNING of ibischk2
> References: <199803311308.WAA12838@mario.tdc.tijp.ti.com>
> Content-Type: text/plain; charset=us-ascii
> Content-Transfer-Encoding: 7bit
>
> Akihiro,
>
> The ibishk2 program is checking the first and last point of your Rising
> and Falling AC Waveforms against the DC VI curves and given test load
> (50 Ohms).
>
> For your case the message indicates that the first point given in the
> Rising Waveform table is .74V.
>
> If you were to plot the intersection of a 50 Ohm to 3V load line (slope
> = 50 V/I) and the given DC VI curve you would see that they interesect
> at .95V (this is fist value in [3] below).
>
> So since
>
> abs(.95 - .74) > 2% * (3 - .74)
> .21 > .045
>
> The checker will print a warning.
>
> The reason for the check is that the first and last points of the AC
> waveforms are supposed to be the stable DC value when driving the given
> load.
>
> Chris Rokusek
> Viewlogic
>
> Akihiro Takegama wrote:
> >
> > To: IBIS-users,
> >
> > Hello, I'm making the IBIS model. But I am confused at ibischk.
> > Could you support me ?
> >
> > I have one question.
> >
> > 1 ) I made the IBIS model within "Rising Waveform" and "Falling
> > Waveform" and I ran the ibischk2. But many warning appeares
> > it's IBIS model, which like as below.
> > Could you please tell me how to calculate the value [3]. ?
> >
> > - ----------------------------------------------------------------------------
> > WARNING - Model 'inout': MIN AC Rising Endpoints ( 0.74V, 3.00V) not within
> > -------------
> > [1]
> >
> > 0.045V (2%) of ( 0.95V, 3.00V) on VI curves for 50 Ohms to 3V
> > ----------- ----------------
> > [2] [3]
> > - -----------------------------------------------------------------------------
> >
> > - Regards,
> > A.Takegama
> >
> > ************************************
> > * Name : Akihiro Takegama *
> > * E-mail : tkgm@tdc.tijp.ti.com *
> > * Corp. : Texas Instruments *
> > ************************************
> > ------- End of forwarded message -------
> ------- End of forwarded message -------
------- End of forwarded message -------
Received on Wed Apr 1 17:41:25 1998
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