[SI-LIST] Re: IBIS for PDN
- From: "Han, Guobing" <han.guobing@xxxxxxxxx>
- To: "Lynne D. Green" <lgreen22@xxxxxxxxxxxxxx>
- Date: Wed, 4 Nov 2009 10:13:32 +0800
Hi Lynne,
Thanks a lot for your reply.
As we know, SPICE model for PDN analysis is very time-consuming
and so-called methodology of Icct is not accurate enough. So I want to
imrpove it by generating IBIS for PDN or by other ways.
Any suggestions?
Thanks,
Guobing
2009/11/4, Lynne D. Green <lgreen22@xxxxxxxxxxxxxx>:
> Hello, Guobing,
>
> The major vendors have PDN analysis software. Each has different
> algorithms and user interfaces. Of the common issues below, the first
> two are probably most important.
>
> Common issues:
> * What functionality do you need? This could include analyzing Z(PDN),
> simulating for current and voltage at each Vcc and GND pin on every IC,
> showing constraint violations for delta_Vcc, running signal integrity
> simulations with PDN effects included, and so forth.
> * Geometric resolution should be small enough to capture such things as
> via fields and microvias.
> * IBIS models should associate I(driver) with a specific POWER and GND
> pin pair, to improve PDN model accuracy in near the IC. This data is
> usually available from the IBIS model maker; unfortunately this data is
> not included in many IBIS models.
> * For modeling of curved areas on the plane, flexible gridding is
> preferred for speed/accuracy tradeoff compared to a fixed grid size.
> With flexible gridding, a coarser grid is used in large plane areas,
> while a finer grid is used near vias and curved edges.
> * PDN analysis should include traces to capacitors and Vcc/GND pins.
> * First order IBIS models that do not describe delta_/delta_Vcc) limit
> accuracy of I(t).
> * Run time tradeoff (fine grids give more accuracy, but take longer).
> One can run a coarse grid for early analysis, and a finer grid for final
> layout. Of course, actual run time also depends on the algorithm and
> implementation.
>
> Regards.
> Lynne Green
>
> "IBIS training when you need it, where you need it."
>
> Dr. Lynne Green
> Green Streak Programs
> http://www.greenstreakprograms.com
> 425-788-0412
> lgreen22@xxxxxxxxxxxxxx
>
>
>
>
> Han, Guobing wrote:
>> Hi all,
>>
>> Have someone tried to study the IBIS for PDN?
>> What's biggest problem and challenge?
>>
>> Thanks,
>> Guobing
>>
>>
>
>
--
Guobing HAN,
Senior Signal Integrity Engineer,
Marvell Shanghai Ltd.
4F,Building4,399 Keyuan RD,Shanghai 201203, China
Email: gbhan@xxxxxxxxxxx
Office: 86-21-61094805
Mobile: 86-13818903075
MSN: han_guobing@xxxxxxxxxxx
Web site: http://www.marvell.com
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