Static Timing Analysis Using Waveform Distortion Augmentation
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Solution Overview
Problem
Current static timing analysis techniques either provide accurate results but are inefficient due to intensive simulations or achieve efficiency but compromise on accuracy, particularly in capturing the effects of waveform distortion in high-density integrated circuits with low operating voltage and longer interconnects.
Innovation Solution
A static timing analysis system that efficiently handles distorted input waveforms by determining transition times, computing waveform distortions, and using augmented circuit models to estimate output waveforms with reduced computational resources, enabling faster and more accurate timing analysis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If full-waveform composite current source noise calculations are performed, then measurement precision is improved, but productivity deteriorates due to intensive circuit simulation
Solution Approach 1:
The patent segments the timing analysis into multiple components: nominal waveform analysis, distortion calculation, and augmented circuit simulation. By separating the distortion calculation from the full waveform simulation, the system can perform accurate timing analysis without the computational burden of full-waveform composite current source noise calculations for every timing path.
Solution Approach 2:
The patent introduces an intermediary approach by using augmented circuit models that incorporate distortion effects without requiring full-waveform simulation. The augmented circuit serves as a mediator between the nominal circuit model and the actual distorted waveform, enabling accurate timing analysis with reduced computational complexity.
2Productivity
If composite current source timing calculations are used, then productivity is improved, but measurement precision deteriorates due to waveform shape distortion
Solution Approach 1:
The patent implements feedback by calculating waveform distortion based on the actual input waveform and using this distortion information to adjust the timing analysis. The distortion calculation feeds back into the augmented circuit model, allowing the system to account for waveform shape effects while maintaining efficient runtime performance.
Solution Approach 2:
The patent changes the parameters used in timing analysis by introducing distortion calculations that account for waveform shape effects. Instead of using fixed nominal waveforms, the system adjusts timing parameters based on calculated distortion values, enabling both efficiency and accuracy.
3Measurement precision
If cell delays are analyzed with distorted waveforms, then measurement precision is improved, but device complexity increases due to additional calculation requirements
Solution Approach 1:
The patent uses copying by creating an augmented circuit model that replicates the original circuit behavior under distorted waveform conditions. This copied model allows the system to analyze timing paths with distorted waveforms without requiring complex modifications to the original circuit analysis infrastructure.
Data Source
AI summary
A system and a method are disclosed for performing static timing analysis. Information describing a distorted input waveform is received by a static timing analyzer. A transition time of the distorted input waveform is determined. Based on the determined input transition time a nominal input waveform and a corresponding nominal output waveform are received. An input waveform distortion is computed based on the nominal input waveform and the distorted input waveform. An output waveform distortion is computed based on an augmented circuit and the input waveform distortion. A distorted output waveform is computed based on the nominal output waveform and the output waveform distortion. The waveforms are represented using the distortion values which are smaller than the actual waveform values, thereby allowing for compact representation. A time-shifted version of an uncoupled input waveform is used to perform conservative timing analysis of circuits that accounts for crosstalk in the circuit.