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New Synopsys timing model challenges Cadence's ECSM

Posted: 26 Oct 2004 ?? ?Print Version ?Bookmark and Share

Keywords:synopsys? cadence design systems? magma design automation? digital ic?

Seeking a more accurate approach to nanometer delay modeling, Synopsys revealed its composite current source (CCS) model at the Synopsys Interoperability Forum here Thursday (Oct. 21). But with Cadence Design Systems and Magma Design Automation backing Cadence's effective current source model (ECSM), EDA users will be confronted with two competing modeling formats.

ECSM, owned by Cadence, is based on current-source modeling as opposed to older voltage-based approaches. Current-source modeling is said to model long interconnects and nonlinear delays more effectively. Cadence has long maintained that ECSM is thus superior to Synopsys' proposed scalable polynomial delay model (SPDM), as well as easier to characterize.

Earlier this week Magma a href="">endorsed ECSM and said it will use that modeling format in its Blast Fusion product. Authors from Cadence and Magma call for ECSM to be adopted as an industry standard in an EDA Views column located at EEdesign.

Synopsys has now joined the current-source bandwagon, but not with ECSM, which Cadence hopes will become an industry standard. Synopsys believes CCS is superior to ECSM, said Rajiv Maheshwary, senior director of marketing for signoff products at Synopsys, because CCS offers more complete receiver modeling.

Maheswary also said that CCS can provide accuracy to within 2 percent of HSpice, and that it provides a scalable methodology that can support statistical design at 65nm.

CCS will be available in the Liberty 2004.12 release, set for December. Tool support for PrimeTime and Library Compiler will come with this release, with Physical Compiler, Astro, and the Star-MTB characterization tool to follow next year.

Eric Filseth, vice president of product marketing for digital ICs at Cadence, said he hasn't heard any complaints about ECSM receiver modeling.

"I think it's inevitable that Synopsys will punt on SPDM and go to a current-source approach," he said. "I hope they use ECSM. It would be really bad for the industry if they come up with a me-too technology and put it in a proprietary data format."

But CCS is freely available as an extension to the open-source Liberty library format, according to Synopsys. ECSM, on the other hand, is proprietary to Cadence, although that company has provided the format to both Magma and Synopsys. Filseth said Cadence is looking for a more formal mechanism to "open it completely" so it can become an industry standard.

- Richard Goering

EE Times

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