Rival RF design flows get a boost

Two former software partners will square off at the Design Automation Conference next month with their respective RF IC design and simulation tools. Agilent Technologies' EEsof group will disclose the first fruits of its partnership with Cadence Design Systems Inc., a platform that integrates EEsof's display and analysis tools into the Cadence RF IC design flow. And Ansoft Corp., a former partner of Agilent's on high-frequency structure simulators which also has links to the Cadence flow, will become a full-blown competitor in RF IC design with the unveiling of Ansoft Designer.

The two platforms are similar in that they offer intelligent tools for simulating the time- and frequency-domain effects of changes in the design and layout of geometry-sensitive radio-frequency circuits. Both platforms will trigger and view multiple simulators from a single screen.

But the tools differ in their degree of intelligence (and, at times, in ease of use) and in their integration with the Cadence IC design environment.

Toward a single flow

The Agilent-Cadence demonstration at DAC, to be held June 10 to 14 in New Orleans, will reveal the results of Phase 1 of a joint research-and-development program the two companies began in February. Overall, the program looks to merge Agilent's Advanced Design System platform (ADS) with Cadence's popular IC design, layout and verification tools to create a single design flow for RF ICs.

In the first phase, popular display and analysis tools from EEsof will be brought completely into the Cadence environment. Analog-cell generator Neolinear Inc. (Pittsburgh) has also declared its intent to be part of this platform with its NeoCircuit-RF software for automatic RF circuit sizing.

When operating the platform tools, a user can call forth Cadence's Spectre RF for time-domain representations and EEsof's harmonic-balance simulator for frequency-domain simulation, as well as other Agilent tools?all from the same Cadence interface. Simulation results are displayed in Cadence screen windows with Agilent's plotters. This capability will be demonstrated for the first time at DAC.

Future intelligence

Future incarnations of the tools, what Cadence and Agilent refer to as Phase 2, will fold intelligence into the selection of the simulation tool in the RF IC design environment. Instead of picking a Spice-like circuit simulation or a harmonic-balance simulation, said Joe Civello, Agilent's ADS platform manager, the user would simply indicate what kind of data he or she is interested in having, and the tools will automatically select and run the appropriate simulators.

This is precisely the kind of intelligence said to be embodied in the Ansoft Designer package. It combines circuit, system and electromagnetic-analysis capabilities with an intuitive user interface and runs on Windows NT/2000/98/XP. It will be priced upwards of $31,900.

The Pittsburgh company's design translators and links to the Cadence environment pit Ansoft Designer as a head-on competitor to the Agilent product.

Ansoft Designer users are free to choose their own analysis tools or to let the software automatically select the best solver for a particular problem, the company said. The product's "solver-on-demand" technology lets users move seamlessly among the software's many model types. These include physics-based electromagnetic models, circuit models and system-level behavioral models, said marketing manager David Vye.

A knowledge-based display system allows the user to track solved data across different levels and screens, he said. A simulation is reinvoked only when circuit or layout modifications have made previous simulations invalid. Besides time-domain, frequency-domain and system-level analysis, Ansoft Designer embodies method-of-moments 3-D planar electromagnetic simulation and 3-D finite-element (or high-frequency structure) simulation.

Cadence link key

The issue of which tool best supports RF IC design may be answered by which company is more tightly linked to the Cadence platform. While the Cadence "connections" program is open to anyone with a serious interest in linking to the Cadence design environment, the Cadence-Agilent agreement is of an entirely different order, said Les Spruiell, who directs RF platform marketing for Cadence. Under this partnership, the companies have committed substantial resources toward research and product development, he said. It was driven by Philips Semiconductors, STMicroelectronics and Motorola, IC makers with complicated design flows and major investments in tools, he said. "We need these tools to work together'," was the message Cadence and Agilent got from these customers, he said.

STMicroelectronics has endorsed the addition of Neolinear to the Cadence-Agilent flow. Neolinear's NeoCircuit-RF automatically resizes circuits for new geometries and manufacturing processes. The three-company design flow was useful in rebuilding a complex low-noise amplifier, said Didier Chapuis, program director of STMicroelectronics' Central Research and Development Group, and shaved many weeks from the design cycle.

? Stephan Ohr

EE Times