Maximal Delay Reduction for RLC-Based Multi-Source Multi-Sink Bus with Repeater Insertion

Signal propagation delay on a multi-source multi-sink bidirectional bus has a dominant effect on high-performance chips. This work presents a novel greedy algorithm that minimizes the critical propagation delay of an RLC-based bus. Based on the topology of a multi-source multi-sink bus and the RLC delay model, the proposed algorithm inserts signal repeaters into the critical path of the RLC-based bus and adjusts their sizes to minimize the maximal propagation delay. This procedure is repeated until no additional improvement is needed. Several buses with various topologies are tested using the proposed algorithm in deep submicron technologies. Experimentally, the critical delay in an RLC-based bus can be reduced dramatically by up to 62.4% with inserted repeater sizes of 24 and execution time of 1.65 s on average. Moreover, average delay reduction, repeater sizes, and running time for 0.18 μm technology are 5.8%, 6.4%, and 26.2%, respectively, better than those of 0.35 μm. Additionally, the topologies of all of the RLC-based buses with inserted repeaters in deep submicron technologies are simulated using HSPICE. The error ratio in the critical delay of a bus with inserted repeaters determined by comparison with HSPICE is 2.7% on average. The proposed algorithm is simple and extremely practical.     

An Analysis of Reducing Communication Delay in Network-on-Chip Interconnect Architecture

This paper presents an Enhanced Clustered Mesh (EnMesh) topology for a Network-on-Chip architecture in order to reduce the communication delay between remote regions by considering the physical positions of remote nodes. EnMesh topology includes short paths between diagonal regions to ensure fast communication among remote nodes. The performance and silicon area overhead of EnMesh are analyzed and compared to those of state-of-the-art topologies such as Mesh, Torus, and Butterfly-Fat-Tree (BFT). Experimental results demonstrate that EnMesh outperforms other existing regular topologies in terms of throughput, latency, packet loss rate, and silicon area overhead.     

VLSI互联线的延时优化研究

首先对互连线模型进行了分析,介绍了插入缓冲器来减小长线延时的方法,然后通过具体计算分析了缓冲器插入的位置、数量,以及尺寸对连线延迟的影响,得出了理论上最理想的优化方案,并给出了结合实际物理设计的优化方案和算法.最后,对一条长互联线的延迟进行了仿真计算,结果证明所给出的算法可有效地减小延时.     

互连线延时和串扰的估算方法

本文综述了集成电路中互连线的延时和串扰的估算方法，分析了各种估算方法的精度和复杂度，同时提出了今后互连线延时和串扰估算所需要解决的新问题。     

Thermal-Aware Methodology for Repeater Insertion in Low-Power VLSI Circuits

In this paper, the impact of thermal effects on low-power repeater insertion methodology is studied. An analytical methodology for thermal-aware repeater insertion that includes the electrothermal coupling between power, delay, and temperature is presented, and simulation results with global interconnect repeaters are discussed for 90- and 65-nm technology. Simulation results show that the proposed thermal-aware methodology can save 17.5% more power consumed by the repeaters compared to a thermal-unaware methodology for a given allowed delay penalty. In addition, the proposed methodology also results in a lower chip temperature, and thus, extra leakage power savings from other logic blocks.     

VDSM集成电路互连特性及RC延迟研究

利用多层金属导体寄生电容模型,详细分析了不同的金属互连线参数对寄生电容的影响,并采用一个闭合公式对超深亚微米级集成电路中的RC互连延迟进行估计.结果表明,当金属导线的纵横比接近2时,线间耦合电容对互连总电容的影响将占主导地位.在超深亚微米工艺条件下,当金属线宽和间距比例W/P的最优质值为0.5～0.6时,计算的互连延迟为最小.此外,还给出了低介电常数材料对互连线电容和延迟的影响,为超深亚微米级的集成电路设计与实现提供有益的参考.     

VLSI互连线的全局优化算法

介绍了通过同时插入缓冲嚣和优化线宽达到互连线时延最小化的方法。为了同时插入缓冲器、优化缓冲嚣尺寸和优化线宽，可以扩展MASM(改进激活集合法)算法。计算结果表明，该算法非常有效。     

深亚微米集成电路设计中的互连线延迟问题

深亚微米集成电路的互连线延迟是设计中需十分重视并必须解决的问题。本文讨论了影响互连线延迟的因素并对深亚微米物理设计的关键步骤中如何考虑并解决互连线延迟问题进行叙述和讨论。     

High-Density Solder Bump Interconnect for MEMS Hybrid Integration

An ultra high-density hybrid integration for micro-electromechanical system (MEMS) mirror chips with several thousand inputs/outputs has been developed. The integration scheme involving flip-chip assembly provides electrical signal to individual mirrors, which is compatible with postprocessing steps of selectively removing the silicon handle and releasing the MEMS mirrors. For the first time, to our knowledge, solder deposition and flip-chip bonding of 3-mum bumps on 5-mum centers of a large array has been demonstrated.     

Fast Variational Interconnect Delay and Slew Computation Using Quadratic Models

Interconnects constitute a dominant source of circuit delay for modern chip designs. The variations of critical dimensions in modern VLSI technologies lead to variability in interconnect performance that must be fully accounted for in timing verification. However, handling a multitude of inter-die/intra-die variations and assessing their impacts on circuit performance can dramatically complicate the timing analysis. In this paper, a practical interconnect delay and slew analysis technique is presented to facilitate efficient evaluation of wire performance variability. By harnessing a collection of computationally efficient procedures and closed-form formulas, process variations are directly mapped into the variability of the output delay and slew. An efficient method based on sensitivity analysis is implemented to calculate driving point models under variations for gate-level timing analysis. The proposed adjoint technique not only provides statistical performance variations of the interconnect network under analysis, but also produces delay and slew expressions parameterized in the underlying process variations in a quadratic parametric form. As such, it can be harnessed to enable statistical timing analysis while considering important statistical correlations. Our experimental results have indicated that the presented analysis is accurate regardless of location of sink nodes and it is also robust over a wide range of process variations.     

Delay Uncertainty Reduction by Gate Splitting

Traditional timing-variation reduction techniques are only able to decrease gate delay variation by incurring a delay overhead. In this brief, we propose a novel and effective splitting-based variation reduction technique for gates. We developed a new tool called Timing Uncertainty Reduction by Gate Splitting (TURGS), which reduces the timing variations of a circuit and presents little delay overhead at the primary output. Our experimental results show that TURGS achieves up to 20% improvement in timing variation for gates.     

分析多芯片组件互连延时的一种新方法

随着多芯片组件工作频率的不断增加，信号延时受互连的影响越来越大，互连已成为决定系统性能的主要因素。延时与冲激响应有着密切的联系，本文采用系统冲激响应的低阶矩，基于双极点近似对互连的延时特性进行了研究。与已有的方法比较，本文的方法提高了极点选择的稳定性，适用于复杂的互连网络。举例证明了这种方法的有效性。     

高性能IC版图综合中的互连线时延估计模型

提出了一组适用于高层综合并考虑各种优化技术的互连时延估计模型,包括最优线宽设计(OWS)、缓冲插入和线宽设计(BIWS)。同Spice给出的模拟结果相比,它们能够给出准确的估计。该模型的时间的阶为一常量。因此,这些简单、快速、准确的模型可用于基于性能要求的集成电路逻辑综合和版图规划。     

Predicting Interconnect Delay for Physical Synthesis in a FPGA CAD Flow

This paper studies the prediction of interconnect delay in an industrial setting. Industrial circuits and two industrial field-programmable gate-array (FPGA) architectures were used in this paper. We show that there is a large amount of inherent randomness in a state-of-the-art FPGA placement algorithm. Thus, it is impossible to predict interconnect delay with a high degree of accuracy. Furthermore, we show that a simple timing model can be used to predict some aspects of interconnect timing with just as much accuracy as predictions obtained by running the placement tool itself. Using this simple timing model in a two-phase timing driven physical synthesis flow can both improve quality of results and decrease runtime. Next, we present a metric for predicting the accuracy of our interconnect delay model and show how this metric can be used to reduce the runtime of a timing driven physical synthesis flow. Finally, we examine the benefits of using the simple timing model in a timing driven physical synthesis flow, and attempt to establish an upper bound on these possible gains, given the difficulty of interconnect delay prediction.     

光纤延迟线对宽带成像雷达的转发式干扰

提出利用光纤延迟线对宽带成像雷达进行转发式干扰的方法,论述光纤延迟线的结构和原理,以及宽带成像雷达的工作原理,并对宽带成像雷达转发式干扰进行仿真。通过分析得到,利用光纤延迟线对雷达信号进行延时和移频,可以有效地对宽带成像雷达进行干扰。     

Optimal Voltage Scaling, Repeater Insertion, and Wire Sizing for Wave-Pipelined Global Interconnects

The simultaneous application of voltage scaling, repeater insertion, and wire sizing is proposed in this paper to achieve high performance, low power, and low area on wave-pipelined interconnect circuits. Based on this methodology, design optimizations for three different types of applications are performed and different design metrics are used to obtain the optimal values of supply voltage, number of repeaters, and interconnect dimensions for these applications. The optimal supply voltage for low-power applications is shown to be twice the threshold voltage. In addition, an optimal throughput-per-energy-area (TPEA) design is compared with low-voltage differential signaling (LVDS). The optimal TPEA design is shown to reduce dynamic power by 10% and wire area by 70% compared to LVDS, without any loss of throughput performance.     

Interconnect Delay Fault Test on Boards and SoCs with Multiple Clock Domains

This paper introduces an interconnect delay fault test (IDFT) controller on boards and system‐on‐chips (SoCs) with IEEE 1149.1 and IEEE 1500 wrappers. By capturing the transition signals launched during one system clock, interconnect delay faults operated by different system clocks can be simultaneously tested with our technique. The proposed IDFT technique does not require any modification on boundary scan cells. Instead, a small number of logic gates needs to be plugged around the test access port controller. The IDFT controller is compatible with the IEEE 1149.1 and IEEE 1500 standards. The superiority of our approach is verified by implementation of the controller with benchmark SoCs with IEEE 1500 wrapped cores.     

基于"有效电容"的耦合RC互连延时分析

本文在保证互连延时特性不变的基础上将两相邻耦合RC互连中的耦合电容和静态互连电路等效为一“有效电容”,并将其用于有源互连的Elmore延时计算。与传统的采用Miller电容的方法进行了比较,它不但提高了计算精度而且反映了延时随信号上升时间变化的规律。本文方法与Elmore延时具有相同的计算复杂度,可广泛用于考虑耦合电容的面向性能的布线优化。     

基于GNSS信号时延特征的转发式欺骗干扰检测算法

针对欺骗干扰情况下准确捕获有效信号困难、大延时欺骗信号及小时延欺骗信号的问题,根据转发式欺骗干扰的信号时延特性,提出了一种信号捕获阶段的联合检测方案。通过检测相关峰的个数实现对大时延转发式欺骗干扰的检测识别,利用相关峰的半高宽(Full Width at Half Maximum, FWHM)变化进行检测检测,完成信号捕获阶段对转发式欺骗信号的检测,仿真证明了设计的有效性。     

基于RLC模型的树形互连线时延估算

文章给出了基于RLC模型的树形互连线50％时延的估算公式。这里给出的算法精度较高(与SPICE仿真结果的误差在10％以内)，而且具有与Elmore时延相同的算法复杂度。该算法基于RLC模型，可以得到各种不同的阻尼响应，包括欠阻尼振荡，而Elmore时延只能反应呈单调变化的过阻尼响应。因此，该算法对阻尼响应的估算精度高于Elmore时延，而其相当的计算开销(算法复杂度)使它可以应用于Elmore时延使用的各个领域。