Consumers nowadays want handheld and portable systems that can do it all—wireless operation, eye-candy video playback, you name it. But many of these crowd-pleasing features involve a great deal of mixed-signal verification.
At 65 nm, the contribution of layout parasitics stemming from interconnects is wreaking havoc on timing closure. Unfortunately, many Spice-based simulators lack the capacity for the job, while fast-Spice variants lose too much in accuracy.
In Discovery AMS 2007, Synopsys has sought to meld the accuracy of Spice with the performance of fast-Spice simulators. Further, Discovery AMS now sports tighter integration between the HSIM fast-Spice engine and the VCS digital simulator, making for higher throughput and greater flexibility in verifying mixed-signal system-on-a-chip designs at all abstraction levels (see the figure).
The culmination of a three-year development effort, the company's XA simulation technology gives the latest revision of Discovery AMS a built-in form of "simulation intelligence" that lets users take advantage of fast-Spice speed without having to be simulation experts.
"Fast Spice is heuristic-based, so users have to set certain configuration files targeted to the circuit being simulated to optimize performance," says Geoffrey Ying, director of marketing for Synopsys' mixed-signal products. "‘Black belts' in fast Spice know how to do this, but average users may not."
Thus, the XA technology offers built-in topology, device, and hierarchy recognition that eliminates the need for setting of simulator configuration files. XA technology is an option for the NanoSim and HSIM simulators.
A user-controlled accuracy command enables easy tradeoff of accuracy and speed. For example, an accuracy setting of one provides the fastest performance, while a maximum setting of seven results in full Spice-level accuracy at the expense of speed.
Discovery AMS 2007 is available now, as is the NanoSim/HSIM XA technology option. Contact Synopsys for package pricing.