RE: [SI-LIST] : FW: Spectraquest Vs. XTK/XNS

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From: Heiko Dudek (heikod@cadence.com)
Date: Wed Oct 04 2000 - 15:22:11 PDT


Ken,

I slightly disagree ... let me explain.

The differentiation between common and differential mode emissions has a very practical
background: the radiation from PCB structures can be categorized into differential mode
and common mode emitters (I think this was first introduced by W. L. Weeks in “Electro-
magnetic Theory for Engineering Applications”, Wiley, 1964). A current loop 'antenna'
would be an emitter for differential mode emissions and a dipole or point source 'antenna'
would be a common mode emitter. Differential mode emissions are relatively easy to handle
even as a pre-layout estimation (SPECCTRAQuest SigXp can do this for you), since the
loop area (formed by the signal path - the trace - and the return path - somewhere on the
reference plane(s)) - as well as frequency and loop current (signal current, calculated in a
standard SI simulation) can be determined. Dipole emitters (e.g. the voltage drop along a
return current path on reference plane structure building dipoles at the edges of a cut-out
or similar things happening in peripheral (conducting components around the PCB) are
way more complicated to model. SPECCTRAQuest uses a 'method of moments' approach
to calculate (both differential and common mode) emissions (you can actually get the near-
field results as well as the far-field emissions) - while not taking anything else into account
than the PCB itself.
And here's where I disagree. Cables are not the origin for common mode emissions, they are
just the emitters (the 'antennas' for TEM waves between reference planes, exited by point
source antennas - large switching currents through vias connecting pwr / gnd to decaps /
comps - if you like). So the real evil to fight is SSN - or, in other words, get your power supply
decoupled correctly. For this purpose we recently announced SQ Power Plane Designer,
it's a DESIGN approach (vs post-layout verification) to get decoupling right.

  - Heiko

At 10:19 AM 10/3/00 -0600, Ken Cantrell wrote:
>Donald,
>Correct me if I'm wrong (Jim), but SQuest, or any of the other vendors other
>than Innoveda(Quiet Ext), only do a differential mode emissions analysis.
>This means that you are not able to analyze the Vcm created between the
>board and the cable(s), where most of your emissions issues come from.
>Don't get me wrong, I'm not pro-Innoveda either, I'm just a user. There are
>issues with all of the packages. Innoveda XTK is antiquated and hard to
>use, plus you have to buy XTK to support Quiet and AC/Grade. They should
>have an XTK lite so that the user has a choice, or make Quiet and AC/Grade
>stand alone. SQuest, HyperLynx, and ICX are more user friendly, but don't
>do common mode. HyperLynx (PADS and Innoveda merged, so HyperLynx is under
>the Innoveda banner now), deserves special note. If you are not designing
>chips, just doing boards, it is the most user friendly and intuitive tool
>out there, and it will do 90% of what you need to do at about 10% of the
>cost. If you are in a multiple product line, manufacturing driven
>situation, and are using Cadence, SQuest has a lot of elements that will
>make your life easier. They make the most highly integrated (with CAD, Mfg,
>and design)package. I also like the agressive pricing that Cadence started
>about a year ago. They give you a lot of bang for the buck. I haven't had
>the chance to review Mentor ICX yet, hopefully later this month. I've had
>problems just getting the package in, both in Seattle and Springs. They
>seem to be responsive on the phone or e-mail, but there is a disconnect
>there somewhere. I have reviewed their FPGA sim pak, Advantage, and it is
>very good. Detailed, but easy to use. I'm hoping their SI pak is as good.
>User to user, Donald, the EDA industry is extremely competitive right now.
>Each vendor leap-frogs the other just about every couple of months on
>feature sets. I used to go for getting everything from one vendor, but now
>I'm mixing and matching, typically doing the one year lease instead of the
>lifetime buy.
>Ken
>Sim Manager
>SRC Computers
>
>-----Original Message-----
>From: owner-si-list@silab.eng.sun.com
>[mailto:owner-si-list@silab.eng.sun.com]On Behalf Of Jim Freeman
>Sent: Monday, October 02, 2000 7:53 PM
>To: Donald Telian
>Cc: May, John; 'si-list@silab.eng.sun.com'
>Subject: Re: [SI-LIST] : FW: Spectraquest Vs. XTK/XNS
>
>
>
>The problem is that the Hspice models are using the M format.
>
>Jim Freeman
>
>
>Donald Telian wrote:
>
> > John,
> >
> > Answers for SPECCTRAQuest are below.
> >
> > Thanks for asking,
> > Donald T.
> > CADENCE
> >
> > At 01:48 PM 9/25/00 -0400, May, John wrote:
> > >
> > >
> > >> -----Original Message-----
> > >> From: May, John
> > >> Sent: Monday, September 25, 2000 1:20 PM
> > >> To: 'si-list@silba.eng.sun.com'
> > >> Subject: Spectraquest Vs. XTK/XNS
> > >>
> > >> Hi all - My group is looking into purchasing one of these tool suites
>for
> > >> SI analysis. I'm wondering what the tradeoffs and limitations of each
>are.
> > >> For instance:
> > >>
> > >> 1) Can botth suites handle HSPICE models in a mixed environment with
>IBIS
> > >> models?
> > >>
> >
> > SPECCTRAQuest uses an optimized spice engine for analysis. As such, all
> > types of spice models can be used with the exception of transistor-based
> > models (M elements). Naturally, IBIS models can be used as well. If you
> > want to use both IBIS and transistor-level IO models, we have a netlist
> > converter that will translate our proprietary spice netlist (extracted
>from
> > PCB layouts or topology drawings) into a variety of other spice formats.
> >
> > >> 2) Do either of the tools have trouble with differential inputs(high
>and
> > >> low inputs used with a differential receiver)?
> > >>
> >
> > SPECCTRAQuest has support for differential drivers and receivers.
> >
> > >> 3) Connector stitching: How easy is it to use these tools for going
> > >> through connectors to model paths that traverse multiple modules?
> > >>
> >
> > It is quite simple to join multiple board layout files together in
> > SPECCTRAQuest for simulation. And that includes package layout (.mcm)
> > files as well. A variety of connector or cable models can be easily
>placed
> > between the boards. The simplest being RLC or RLGC representations, but
> > fully-coupled connector models can also be integrated into the simulation.
> > This normally requires some re-formatting of the data from the connector
> > vendor, but it is not too hard to do assuming you understand how to build
> > and call spice subcircuits.
> >
> > >> John
> > >
> > >**** To unsubscribe from si-list or si-list-digest: send e-mail to
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> > >
> > >
> > >
> > Donald Telian
> > Cadence Design Systems
> > phone: 408-944-7791
> > donaldt@cadence.com
> >
> > **** To unsubscribe from si-list or si-list-digest: send e-mail to
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>
>
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>
>
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     Heiko Dudek
     Technical Marketing Manager | High Speed Systems Design & IC Packaging
     Cadence Design Systems | 270 Billerica Road | Chelmsford, MA 01824
     
     ph: (978) 262-6384
     fx: (978) 446-6798
     email: heikod@cadence.com

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