IBIS-USERS - EIA IBIS Open Forum Users Activity: Re: [IBIS-Users

From: Syed Huq <shuq@cisco.com>
Date: Thu Oct 07 2004 - 06:59:33 PDT

Hi Vivek,

The spice netlist that is an input to s2ibis2 *will* contain the
instance of the subckt. This is in the .sp file which is called by .s2i
file.

In the .s2i file there should be a line like this:

[Spice file] MySpiceNetlist.sp

In the MySpiceNetlist.sp, all your SUBCKT will reside.

- Syed

attached mail follows:

Hi,

Thx for all ur help.

This is how is understand the generation of the IBIS Model. The subckt of
which i need to generate the IBIS Model is mentioned as the name of the model in
the [Model] section of the command file.

I observe that in the original spice netlist that i have got does not contain
the instance of the subckt. Maybe this the reason that i dont see any simulation
changes happening in the output IBIS file. I get either the same data for the
V/I V/T curves or i get 0.0000 as all the values.

Now....does the spice netlist that is an input to s2ibis2 contain the instance
of the subckt or does s2ibis2 create the instance on its own in the intermediate
.spi file ?

Thx,
Vivek

                      "Syed Huq"
                      <shuq@cisco.com> To: "Vivek Kumar Sundriyal" <Vivek.Kumar.Sundriyal@nsc.com>
                      Sent by: cc: ibis-users@eda.org, owner-ibis-users@eda.org
                      owner-ibis-users@ Subject: Re: [IBIS-Users] dV/dT = 0.0000/0.00000
                      eda.org


                      10/06/04 09:42 PM

It means during the transient simulation, the device did not switch. The
waveform is flat. So s2ibis2 was unable to calculate dV/dT.
Most likely a setup problem.

- Syed

----- Message from "Vivek Kumar Sundriyal" <Vivek.Kumar.Sundriyal@nsc.com> on
Wed, 6 Oct 2004 19:02:10 +0530 -----

      To: ibis-users@eda.org

      cc: owner-ibis-users@eda.org

Subject: Re: [IBIS-Users] dV/dT =
          0.0000/0.00000

Hi,

I am new user of IBIS and am trying to generate the IBIS Model for one of our
I/O pads.

I get the following error on trying ibischk4 on the generated IBIS Model. The
IBIS Model is generated using the s2ibis2.

ERROR (line 320) - dV must be greater than 0 in a Ramp specification
ERROR (line 320) - dT must be greater than 0 in a Ramp specification
ERROR (line 320) - dV must be greater than 0 in a Ramp specification
ERROR (line 320) - dT must be greater than 0 in a Ramp specification
ERROR (line 320) - dV must be greater than 0 in a Ramp specification
ERROR (line 320) - dT must be greater than 0 in a Ramp specification
ERROR (line 321) - dV must be greater than 0 in a Ramp specification
ERROR (line 321) - dT must be greater than 0 in a Ramp specification
ERROR (line 321) - dV must be greater than 0 in a Ramp specification
ERROR (line 321) - dT must be greater than 0 in a Ramp specification
ERROR (line 321) - dV must be greater than 0 in a Ramp specification

ERROR - Model ABCXYZ: The [Rising Waveform]
      with [R_fixture]=50 Ohms and [V_fixture]=0V
      has TYP column DC endpoints of 0.00V and 0.00v, but
      an equivalent load applied to the model's I-V tables yields
      different voltages (-0.00V and -0.00V),
      a difference of 863.34% and 963.34%, respectively.
ERROR - Model ABCXYZ: The [Rising Waveform]
      with [R_fixture]=50 Ohms and [V_fixture]=3.3V
      has TYP column DC endpoints of 3.30V and 3.30v, but
      an equivalent load applied to the model's I-V tables yields
      different voltages ( 3.30V and 3.30V),

can anyone let me know the cause of this error ?

and i get dV/dT = 0.0000/0.00000 which is wrong ?

what can be the cause of the error ?

Any help is appreciated.

Thx,
Vivek

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