RE: using IBIS in HSPICE

Perry,

Several possible reasons:

1. One is as Adam said.
2. How about your pulse width vs time span in V-t curve?
   If V-t curve time span is longer than pulse width, you may cut
   V-t curve time span as slightly shorter than pulse width.
3. Is 50 Ohms the load for V-t curve?

Best regards.

Brian

-----Original Message-----
From: Adam.Tambone@fairchildsemi.com
[mailto:Adam.Tambone@fairchildsemi.com]
Sent: Tuesday, June 19, 2001 8:14 AM
To: Perry Qu
Cc: IBIS group
Subject: Re: using IBIS in HSPICE

Perry,

There are two options in HSPICE that allow you to use V-t data of the
rising and falling waveforms of the IBIS model instead of the Ramp data in
the IBIS model. If you do not specify these options then by default HSPICE
will use the Ramp data.

They are...

ramp_fwf = 0 or 1 or 2
ramp_rwf = 0 or 1 or 2

If you specify 0 then ramp data will be used.
If you specify 1 then 1 waveform will be used.
If you specify 2 then 2 waveforms will be used.

See Chapter 19 of the most recent Star-HSPICE Manual (2000.4) for a full
explanation.

Adam Tambone

"Perry Qu" <perry.qu@alcatel.com> on 06/19/2001 10:45:05 AM

To: IBIS group <ibis-users@eda.org>
cc:

Subject: using IBIS in HSPICE

Hi!

I tried to do some simulation in HSPICE with a differential driver in
IBIS format. The driver is a HSTL output and by connecting the driver
just to a simple 50 ohm load, I observed unrealistic sharp falling edge.
When I check the HSPICE log file, I have the following message:

 ** warning** iob_eles2:102:
    Inconsistency between Ramp and PD/PU data is detected.
    dV_f= 3.2680E-01 V_fwf_max= 3.3000E+00 V_fwf_min= 3.3000E+00
    transition from 80% to 20% is not satisfied

 ** warning** iob_eles2:186:
    099 instances of out-of-range states at falling ramp
    this can detriment accuracy

Any idea how I can correct the problem?

Thanks in advance.

Perry Qu

(See attached file: perry.qu.vcf)

 
Received on Tue Jun 19 12:32:54 2001