Cadence adds a new Fast SPICE Circuit Simulator

In the early years of Cadence their growth was bolstered through many well-timed acquisitions, however over the last several years I’ve noticed a distinctively different trend where they have internally developed EDA tools. I had a Zoom call with Jay Madiraju from Cadence, who markets their newly announced Fast SPICE tool called Spectre FX, developed internally. We first met back in 2003 while working at another EDA company on their Fast SPICE circuit simulator, so Jay really knows the SPICE market place quite well.

Simulator Family

Cadence now offers three SPICE circuit simulators, each serving a different engineering purpose:

• Spectre X – Focus on accuracy, analog characterization
• Spectre FX – Focus on capacity and simulation speed
• Spectre AMS Designer – Mixed-signal, mixed-language, mixed-level with Xcelium logic simulation

These three circuit simulators now cover the complete spectrum of accuracy, capacity and speed that IC designers need to design and optimize their semiconductor IP for timing and power:

The market segments that Cadence serves can be divided into eight categories, and it’s part of what they call an Intelligent System Design strategy:

A circuit design engineer using Spectre FX can now quickly simulate some of the largest transistor-level netlists for DRAM, Flash and SRAM memories, because of the high-capacity in a Fast SPICE tool. Interconnect now dominates the speed of a chip, more than the transistor switching, so using a Fast SPICE simulator on post-layout netlists is essential to predicting silicon speed during the design phase.

Tuning

It was at UC Berkeley that the first SPICE simulator was developed, and historically SPICE simulators have used dozens of arcane options to control internal parameters like DC convergence, iteration methods and accuracy settings. Spectre FX takes a different approach by providing default settings that work well for most IC designs, and then letting you decide how to trade-off accuracy for simulation speed with a simple option.

Interactive Simulation

Another vestige of Berkeley SPICE is that most SPICE simulators are purely batch oriented, where you setup the time duration, launch the job, then patiently wait for results. With Spectre FX there’s also the interactive mode of using the tool, so a circuit designer can start a job, pause, make measurements, then optionally decide to save the simulation results as a starting point for a subsequent run, or continue simulating.

Speed and Capacity

Traditional SPICE uses a single, large matrix to simultaneously solve for currents and voltages, while Fast SPICE does automatic partitioning into many, smaller matrixes, and uses event-driven methods between partitions. What makes the Cadence approach unique is the emphasis on exploiting Multi Threading for efficient use on up to 32 cores. The claim is that this approach shows up to 3X faster simulation results than the competitors, and here’s some direct comparisons on six different design types:

Early Customers

It’s a real challenge to get actual customers talking about using a new circuit simulator, because they often don’t want competitors to know how to get faster results and improve time to market. Kudos to Cadence for getting some well-known semiconductor design companies to talk about using Spectre FX, including MediaTek, Renesas and JVCKENWOOD.

Summary

Cadence has filled out their SPICE circuit simulator family to include Fast SPICE in the new Spectre FX tool, and here’s how that fits into the bigger family of EDA tools:

The field for SPICE circuit simulators just got more competition, and that always gives customers better value for their money. Read more about Spectre FX on the Cadence site.

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