[SI-LIST] Re: What do you do when the manufacturer's model doesn't match the measurements?
- From: steve weir <weirsi@xxxxxxxxxx>
- To: "Katkoria, Deepak" <Katkoria.Deepak@xxxxxxxxxxx>
- Date: Mon, 30 Aug 2010 00:39:01 -0700
$15K o $25K sounds high. If you are paying that kind of money for your
measurement based models, you should shop around more.
Steve.
Katkoria, Deepak wrote:
> Hi Iain,
> Usually vendor don't gives a guarantee about the model..
>
> You need to check the file, if some reading are not according to device then
> you can ask for circuit used for simulation.
>
> They will give you a RLC diagram..
> Otherwise you have to look for 3rd party, who can create a model for you..
> They charge from 15K to 25K depends upon time..
>
> I have faced similar problem in past..
>
> You can even ask for spice model and create your own Ibis model..
> For ask for IO cell parameters(technology used) and based on that you can
> create the Ibis model..
>
>
> Deepak
>
>
> -----Original Message-----
> From: si-list-bounce@xxxxxxxxxxxxx [mailto:si-list-bounce@xxxxxxxxxxxxx] On
> Behalf Of Iain Waugh
> Sent: Friday, August 27, 2010 3:00 PM
> To: si-list@xxxxxxxxxxxxx
> Subject: [SI-LIST] What do you do when the manufacturer's model doesn't match
> the measurements?
>
> Hi all, please can you advise!
>
> Our aim is to prove the vendors' IBIS models on a dev board so we can have
> confidence that simulations of our own 400MHz DDR2 design (using the same
> parts) will be accurate. We're simulating with Hyperlynx 8.0 and have taken
> the most up-to-date IBIS models from the vendors' websites.
>
> We've made a pretty good free-form schematic model of the dev board with the
> target CPU and memories (plus 'scope probe at the receiver's pin). The
> initial simulations were horrible with a massively non-monotonic rising edge
> crossing the Vil and Vih levels of the receiver twice. We used a 6GHz LeCroy
> 'scope with 1GHz probes to measure the actual dev board's signal integrity
> and the edges were clean.
>
> In my mind, that proves that I can't trust the model. The catch, however, is
> that the vendor then told us to put the simulation probes at the die instead
> of at the pin. We re-simulated and the non-monotonic edges went away - they
> actually looked like the measurement!
>
> Would you trust the results of a simulation when the measured case only
> correlates with a simulation having probes in a different place? Can we use
> the wrong (but matching) model to guide us to the best routing topology? I'm
> tempted to just use standard good SI practises and ignore the simulations.
>
> Best regards,
>
> Iain Waugh
>
> ------------------------------------------------------------------
> To unsubscribe from si-list:
> si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field
>
> or to administer your membership from a web page, go to:
> //www.freelists.org/webpage/si-list
>
> For help:
> si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field
>
>
> List technical documents are available at:
> http://www.si-list.net
>
> List archives are viewable at:
> //www.freelists.org/archives/si-list
>
> Old (prior to June 6, 2001) list archives are viewable at:
> http://www.qsl.net/wb6tpu
>
>
>
> The information contained in this message may be confidential and legally
> protected under applicable law. The message is intended solely for the
> addressee(s). If you are not the intended recipient, you are hereby notified
> that any use, forwarding, dissemination, or reproduction of this message is
> strictly prohibited and may be unlawful. If you are not the intended
> recipient, please contact the sender by return e-mail and destroy all copies
> of the original message.
>
> ------------------------------------------------------------------
> To unsubscribe from si-list:
> si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field
>
> or to administer your membership from a web page, go to:
> //www.freelists.org/webpage/si-list
>
> For help:
> si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field
>
>
> List technical documents are available at:
> http://www.si-list.net
>
> List archives are viewable at:
> //www.freelists.org/archives/si-list
>
> Old (prior to June 6, 2001) list archives are viewable at:
> http://www.qsl.net/wb6tpu
>
>
>
>
--
Steve Weir
IPBLOX, LLC
150 N. Center St. #211
Reno, NV 89501
www.ipblox.com
(775) 299-4236 Business
(866) 675-4630 Toll-free
(707) 780-1951 Fax
------------------------------------------------------------------
To unsubscribe from si-list:
si-list-request@xxxxxxxxxxxxx with 'unsubscribe' in the Subject field
or to administer your membership from a web page, go to:
//www.freelists.org/webpage/si-list
For help:
si-list-request@xxxxxxxxxxxxx with 'help' in the Subject field
List technical documents are available at:
http://www.si-list.net
List archives are viewable at:
//www.freelists.org/archives/si-list
Old (prior to June 6, 2001) list archives are viewable at:
http://www.qsl.net/wb6tpu
Other related posts:
