| Title | Pessimism Reduction in Coupling-Aware Static Timing Analysis Using Timing and Logic Filtering |
| Author | *Debasish Das (Northwestern Univ., United States), Kip Killpack, Chandramouli Kashyap, Abhijit Jas (Intel, United States), Hai Zhou (Northwestern Univ., United States) |
| Page | pp. 486 - 491 |
| Keyword | static timing analysis, crosstalk, algorithm |
| Abstract | With continued scaling of technology into nanometer regimes, the impact of coupling induced delay variations are significant. While several coupling aware static timers have been proposed, the results are often pessimistic with many false failures. We present an integrated iterative timing filtering and logic filtering based approach to reduce pessimism. We use a realistic coupling model based on arrival times and slews and show that non-iterative pessimism reduction algorithms proposed by previous research
can give potentially non-conservative timing results. On a functional block from an industrial 65nm microprocessor our algorithm showed a maximum pessimism reduction of 11.18\% of cycle time over converged timing filtering analysis that does not consider logic constraints. |
| Title | A Fast Incremental Clock Skew Scheduling Algorithm for Slack Optimization |
| Author | *Kui Wang, Hao Fang, Hu Xu, Xu Cheng (Microprocessor Research Center of Peking University, China) |
| Page | pp. 492 - 497 |
| Keyword | clock schedule , semi-synchronous circuits, useful skew, timing analysis |
| Abstract | We propose a fast clock skew scheduling
algorithm which minimizes clock period and enlarges the slacks of
timing critical paths. To reduce the runtime of the timing
analysis engine, our algorithm allows the sequential graph to be
partly extracted. And the runtime of itself is almost linear to
the size of the extracted sequential graph. Experimental results
show its runtime is less than a minute for a design with more than
ten thousands of flip-flops. |
| Title | Clock Tree Synthesis with Data-Path Sensitivity Matching |
| Author | *Matthew R. Guthaus (University of California Santa Cruz, United States), Dennis Sylvester (University of Michigan, United States), Richard B. Brown (University of Utah, United States) |
| Page | pp. 498 - 503 |
| Keyword | clock tree synthesis, variability, skew |
| Abstract | This paper investigates methods for
minimizing the impact of process variation on clock skew using
buffer and wire sizing. While most papers on clock trees ignore
data-path circuit variations and most papers on data-path circuit
optimization disregard clock tree variation, we consider
both. Using both clock and data-path variations together, we
present a novel sensitivity-matching algorithm that allows clock
tree skews to be intentionally correlated with data-path
sensitivities to ameliorate timing violations due to variation.
Our statistical tuning shows an improvement in terms of expected
clock skew and clock skew variation over previously published
robust algorithms. |
| Title | Buffered Clock Tree Synthesis for 3D ICs Under Thermal Variations |
| Author | Jacob Minz (Synopsys, United States), Xin Zhao, *Sung Kyu Lim (Georgia Inst. of Tech., United States) |
| Page | pp. 504 - 509 |
| Keyword | thermal-aware optimization, clock, 3D IC |
| Abstract | In this paper, we study the buffered clock tree synthesis problem under thermal variations for 3D IC technology. Our major contribution is the Balanced Skew Theorem, which provides a theoretical background to efficiently construct a buffered 3D clock tree that minimizes and balances the skew values under two distinct non-uniform thermal profiles. Our clock tree synthesis algorithm named BURITO (Buffered Clock Tree With Thermal Optimization) first constructs a 3D abstract tree under the wirelength vs via-congestion tradeoff. This abstract tree is then embedded, buffered, and refined under the given non-uniform thermal profiles so that the temperature-dependent skews are minimized and balanced. Experimental results show that our algorithms significantly reduce and perfectly balance clock skew values with minimal wirelength overhead. |
| Title | Analytical Model for the Impact of Multiple Input Switching Noise on Timing |
| Author | Rajeshwary Tayade (University of Texas at Austin, United States), *Sani Nassif (IBM, United States), Jacob Abraham (University of Texas at Austin, United States) |
| Page | pp. 514 - 517 |
| Keyword | multiple input switching, dynamic variability, path delay estimation |
| Abstract | The timing models used in current Static Timing Analysis tools characterize gate delays only for single input switching
events. It is well known that the temporal proximity of signals arriving at different inputs causes significant variation in the gate delay. This variation in delay needs to be accounted for when selecting critical paths of a circuit. In this paper, a detailed analysis of Multiple Input Switching (MIS) behavior is presented that leads to a simple analytical model which can be used to estimate gate delay with MIS noise. The model presented requires minimum additional characterization effort, and can be employed in a statistical timing engine. The dynamic delay variability of a path caused due to MIS noise can be accurately estimated using the proposed model. |