[SI-LIST] Re: HyperLynx vs Hspice

Hi Naveen:

Your questions (coincidentally) are being addressed in a Mentor Webinar early 
next week http://www.mentor.com/pcb/events/highspeed_webinar_reg.cfm.  Kind of 
down to the wire, but I think you can still sign up, if you're interested.

Specific to your questions ...

> 1. Can I use just Hspice to perform all my high speed 
> simulations or is
> HyperLynx a better tool for this application?

At the board level, HSPICE is simply out of the question.  

> 2. Has anyone had experience with converting 3D spice models to IBIS?
> What are the tradeoffs?

There are a number of things that you can do in SPICE, like modeling 
pre-emphasis or equalization, for example, that don't work well in IBIS.  IBIS 
4.0 addresses this, enabling calls to external models.  The implied need here 
is that IBIS needed a boost, particularly for modeling multi-gigabit circuits.  
 

> 3. HyperLynx has three levels of licenses - regular, EXT and 
> GHZ. Which
> one should I be using?

Among the options you listed, "HyperLynx GHz" was developed for the purpose 
you're describing.  A bit more detail below.

> I need to perform some high speed simulations (over 3GHz) for my
> backplane and I currently have the Mentor HyperLynx tool. I have run
> into a little problem. HyperLynx needs IBIS models for simulation
> purposes, whereas most of the vendors provide only spice 
> models and not
> IBIS. Although HyperLynx can convert Spice models to IBIS, it 
> does need
> a Spice simulator to do that.

HyperLynx GHz can work with either IBIS or HSPICE models.  Provided that you 
have an HSPICE license, the tool just invokes the simulator that would be best 
for the circuit you're analyzing.  Obviously, for example, you'd want an 
IBIS-optimized simulator for your non-3GHz signals (rather than HSPICE).  And, 
conversely, you'd want to be using HSPICE to model the 3 GHz signals for which 
you have encrypted HSPICE models.  So, to state it correctly, HyperLynx GHz 
doesn't actually "convert" SPICE models into IBIS models.  It just grabs the 
best available simulator for the IC models it finds.

Does that make sense?

Bill Hargin
Mentor Graphics Corp.
Systems Design Division
High-Speed Tools
425-497-5079 - Direct
425-301-4425 - Mobile


> -----Original Message-----
> From: Naveen Reddy [mailto:naveenr@xxxxxxxxxxxxxxx]
> Sent: Friday, September 26, 2003 10:38 AM
> To: si-list@xxxxxxxxxxxxx
> Subject: [SI-LIST] HyperLynx vs Hspice
> 
> 
> Hi Everybody:
> I need to perform some high speed simulations (over 3GHz) for my
> backplane and I currently have the Mentor HyperLynx tool. I have run
> into a little problem. HyperLynx needs IBIS models for simulation
> purposes, whereas most of the vendors provide only spice 
> models and not
> IBIS. Although HyperLynx can convert Spice models to IBIS, it 
> does need
> a Spice simulator to do that.
> 
> I am a little confused here and am hoping I can have these questions
> answered.
> 
> 1. Can I use just Hspice to perform all my high speed 
> simulations or is
> HyperLynx a better tool for this application?
> 2. Has anyone had experience with converting 3D spice models to IBIS?
> What are the tradeoffs?
> 3. HyperLynx has three levels of licenses - regular, EXT and 
> GHZ. Which
> one should I be using?
> 
> Thanks in advance.
> 
> -Naveen.
> 
> 
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