When putting together a suite of models for high-speed pc-board simulation, you'll rarely, if ever, come up with a set of models that are all in the same format or language. Intellectual-property vendors further compound the issue, as they never seem to run out of clever new buffering schemes for which accurate models are available only in Spice or VHDL-AMS formats.

Version 3.0 of Mentor Graphics' ICX simulator lets pc-board designers use signal-integrity models created in multiple languages simultaneously. The simulator leverages technology from the company's ADVanceMS mixed-mode simulation environment for IC designers. ICX 3.0 supports models in IBIS (Input/Output Buffer Information Specification) format; three different types of Spice models (Eldo, HSpice, and Berkeley Spice); and VHDL-AMS.

According to Kevin Cohen, Mentor's marketing manager for high-speed pc-board signal-integrity products, buffer technologies such as adaptive drivers and receivers typify the kinds of circuits that call out for what Mentor is calling "multilingual simulation." Dynamic circuits such as these are difficult to model with IBIS, which lends itself to static representations. The alternative is a tedious process of manually customizing the IBIS models coupled with a specialized simulation environment.

Users can sidestep Spice-to-IBIS model conversions be-cause they'll be able to mix and match IBIS syntax along with Spice and VHDL-AMS in the same buffer. It also enables model mixing within a given pc-board net.