[SI-LIST] Re: DC Drop in PDN simulation
- From: Dan Oh <doh@xxxxxxxxxx>
- To: "mnithink@xxxxxxxxx" <mnithink@xxxxxxxxx>, matthew leslie <mbleslie@xxxxxxxxx>
- Date: Fri, 30 Aug 2013 08:02:23 -0700
Hi Nithin,
This may be a drift instead of DC offset due to lack of on-chip decoupling cap
and resistance.
Try increasing your ODC to very large value and reducing ODR to zero and see.
Best,
-Dan Oh
-----Original Message-----
From: si-list-bounce@xxxxxxxxxxxxx [mailto:si-list-bounce@xxxxxxxxxxxxx] On
Behalf Of Nithin Kumar
Sent: Friday, August 30, 2013 7:56 AM
To: matthew leslie
Cc: si-list@xxxxxxxxxxxxx
Subject: [SI-LIST] Re: DC Drop in PDN simulation
Hi Matthew,
Thanks.
The reference impedance used for extracting s-parameter models is 0.01mohms.
I did a freq domain analysis (Z11) connecting die,package and pcb models.
The response looks alright with low impedance( of around 1 mohm) near DC.
so I would expect a very low DC offset but this isn't the case. I'm not
able to figure out the possible reason.
Regards,
Nithin
On Fri, Aug 30, 2013 at 8:14 PM, matthew leslie <mbleslie@xxxxxxxxx> wrote:
> [image: Boxbe] <https://www.boxbe.com/overview> matthew leslie (
> mbleslie@xxxxxxxxx) is not on your Guest
> List<https://www.boxbe.com/approved-list?tc_serial012227189&tc_randH9907851&utm_source=stf&utm_medium=email&utm_campaign=ANNO_MWTP&utm_content>
>
> sender<https://www.boxbe.com/anno?tc_serial012227189&tc_randH9907851&utm_source=stf&utm_medium=email&utm_campaign=ANNO_MWTP&utm_content>
>
> domain<https://www.boxbe.com/anno?tc_serial012227189&tc_randH9907851&utm_source=stf&utm_medium=email&utm_campaign=ANNO_MWTP&utm_content>
> In general, s-parameter models are not reliable below a certain frequency
> range. It depends on the extraction tool, but typically that range is
> around 1-100MHz. Sometimes the tool refuses to extract below a certain
> frequency (I believe HFSS does this). Sometimes the tool will agree to
> generate a model for low frequencies, but that model is erroneous. For
> example, the tool might simply extrapolate "accurate" data in the 1-10MHz
> range down to kHz and DC. Other tools switch the field solver techniques
> when transitioning to lower frequencies and as a result end up creating
> models with discontinuities in insertion/return loss.
>
> There are some steps you can take to better ensure accuracy at low freq
> for s-param model. Make sure you are using a low reference impedance, such
> as 1-ohm or 0.1ohm. Also, if your solver permits, try forcing a separate DC
> solution into s-param model. Unfortunately, this doesn't guarantee accuracy
> from DC up to the 1-100MHz range.
>
> S-parameter models that are accurate from DC to multi-GHz (as far as I
> know) is a big challenge. If I were you, I might move to creating an RLGC
> or other type of lumped element model for more accurate low frequency
> representation.
>
>
> On Fri, Aug 30, 2013 at 8:26 AM, Nithin Kumar <mnithink@xxxxxxxxx> wrote:
>
>> Hello Experts,
>> I'm doing PDN simulation using DIE model ( from Redhawk), PCB model and
>> Package model (s-parameter)
>> During transient analysis I'm seeing huge drop at the bga balls as well as
>> die bump.
>> I have verified the resistance values of package and PCB ( which are very
>> small) and varied DIE R as well. But i'm not able to reduce this huge DC
>> offset.
>> can anybody through some light on possible reasons for such an offset?
>>
>> --
>> -------------------
>> Regards,
>> Nithin Kumar
>>
>>
>> ------------------------------------------------------------------
>> 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 forum is accessible at:
>> http://tech.groups.yahoo.com/group/si-list
>>
>> 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
>>
>>
>>
>
>
> --
> Matthew B. Leslie
> mbleslie@xxxxxxxxx
>
>
--
-------------------
Regards,
Nithin Kumar
------------------------------------------------------------------
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 forum is accessible at:
http://tech.groups.yahoo.com/group/si-list
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
Confidentiality Notice.
This message may contain information that is confidential or otherwise
protected from disclosure. If you are not the intended recipient, you are
hereby notified that any use, disclosure, dissemination, distribution, or
copying of this message, or any attachments, is strictly prohibited. If you
have received this message in error, please advise the sender by reply e-mail,
and delete the message and any attachments. Thank you.
------------------------------------------------------------------
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 forum is accessible at:
http://tech.groups.yahoo.com/group/si-list
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:
