Tool generates variation-aware timing models

Variety is an ultrafast general-purpose statistical library characteriser for standard cells.

Altos Design Automation has announced its second product: Variety is an ultrafast general-purpose statistical library characteriser for standard cells.

The new tool generates variation-aware timing models for use with commercial statistical static timing analysis (SSTA) tools from Extreme Design Automation, Cadence Design Systems and Synopsys.

Other formats will be supported in future releases, including the SSTA standard format from Si2's Open Modelling Coalition.

Variety characterises for both systematic and random variation.

Random variation, which can account for more that 50% of the total variation for sub90nm processes, represents a significant new challenge to characterisation run-time as it requires modelling the impact on each individual transistor within a cell.

This could potentially increase characterisation runtime by 20x without sophisticated algorithms to enhance the performance.

Variety leverages the "inside view" approach that Altos pioneered for Liberate, their nonstatistical library characteriser, to keep the overhead of random variation characterisation to 3x or less of nominal characterisation.

Yoshio Inoue, Chief Engineer of Advanced Design Framework Development Dept at Renesas Technology Corp said: "The basis for statistical analysis and optimisation is a highly accurate statistical cell library that is derived from key process parameter variations".

Inoue continued: "We selected Altos' Variety because of its fast performance, the quality of its models and its ability to support multiple tool vendor formats from a single characterisation run".

"We are using Variety to develop the libraries needed for our next generation variation aware design flow".

"We are very pleased to have Variety selected by Renesas Technology Corp to enable the creation of SSTA models for their statistical design flow", said Jim McCanny, Altos CEO.

"Using statistical analysis will enable Renesas to achieve faster timing closure and improved yields as it significantly reduces the pessimism inherent in traditional corner-based timing analysis".

"Fundamental to SSTA is the statistical library that Variety generates".

Variety creates SSTA models that include nominal timing information plus additional data representing the impact of any number of parameter variations.

All library timing data are characterised for variation including delays, transitions, timing constraints and pin capacitances.

Both linear and nonlinear models can be created as well as driver and receiver current source models such as composite current source (CCS) and effective current source models (ECSM).

"For SSTA to become widely adopted there needs to be an easy, efficient and consistent way of creating the library views that SSTA needs", said Ken Tseng, Altos CTO and founder.

"With Variety, Altos has reduced the burden for creating SSTA models to be equivalent to creating corner based timing models when compared with using other commercial or in-house characterisation tools".

Variety is available now.

US pricing starts at $95,000 for a 1 year licence.

Altos' products are sold directly in North America and via distributor Marubeni Solutions Corp in Japan.

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