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We develop two novel globally-informed gate-sizing algorithms for tackling the problems of statistical circuit timing optimization under a timing yield constraint, and timing yield optimization under a timing (i.e., delay) constraint. Unlike previous works, our techniques are global in the sense that they use objective functions that take into account either the entire circuit's variabilities and...
This paper presents a gate delay estimation method that takes into account dynamic power supply noise. We review STA based on static IR-drop analysis and a conventional method for dynamic noise waveform, and reveal their limitations and problems that originate from circuit structures and higher delay sensitivity to voltage in advanced technologies. We then propose a gate delay computation that overcomes...
A clock distribution network (CDN) insensitive to process, voltage, and temperature (PVT) variations is presented in this paper. Unlike a traditional source-synchronous interface, the CDN uses a current-mode logic (CML) divider and sense- amp-based data receiver for data capture and deserialization. The proposed input path extends its operating range beyond 4- Gb/s/pin without the need for retraining...
For timing analysis, each flip-flop and latch in a standard library is characterized for two constraints: setup time and hold time constraints. These constraints need to be characterized for their sensitivities to the variation parameters in order to perform statistical timing analysis. Several approaches have been proposed to perform statistical characterization of delays. However, the predominant...
Statistical analysis is generally seen as the next EDA technology for timing and power sign-off. Research into this field has seen significant activity started about five years ago. Recently, interest appears to have fallen off somewhat. Also, while a lot of focus has been put on research fundamentals, extremely few applications in industry have been reported so far. Therefore, a group including Infineon...
Process and environmental variations continue to present significant challenges to designers of high-performance integrated circuits. In the past few years, while much research has been aimed at handling parameter variations as part of timing analysis, few proposals have actually included ways to interpret the results of this parameterized static timing analysis (PSTA) step. In this paper, we propose...
With the adoption of statistical timing across industry, there is a need to characterize all gates/cells in a digital library for delay variation (referred to as statistical characterization). Statistical characterization needs to be performed efficiently with acceptable accuracy as a function of several process and environmental parameter variations. In this paper, we propose an approach to consider...
This paper presents an allocation method of decoupling capacitance that explicitly considers timing. We have found and focused that decap does not necessarily improve a gate delay at all the switching timing within a cycle, and devised an efficient sensitivity calculation of timing to decap for decap allocation. The proposed method, which is based on a statistical noise modeling and timing analysis,...
In order for the results of timing analysis to be useful, they must provide insight and guidance on how the circuit may be improved so as to fix any reported timing problems. A limitation of many recent variability-aware timing analysis techniques is that, while they report delay distributions, or verify multiple corners, they do not provide the required guidance for re-design. We propose an efficient...
Statistical static timing analysis (SSTA) methods, which model process variations statistically as probability distribution functions (PDFs) rather than deterministically, have emerged to more accurately portray integrated circuit performance. This analysis has been thoroughly performed on traditional zero clock skew circuits where the synchronizing clock signal is assumed to arrive in phase with...
This document presents a compilation of results from tests performed by iRoC Technologies on SER induced by alpha particles on SRAM memories for technology nodes from 180 nm to 65 nm. The aim of this study is to establish the variation of sensitivity with technology node for SEU and MCU, and to analyze the possible influence of different designs and technological parameters at a given technology node.
In this paper, we present a new technique to improve the reliability of H-tree SRAM memories. This technique deals with the SRAM power-bus monitoring by using built-in current sensor (BICS) circuits that detect abnormal current dissipation in the memory power-bus. This abnormal current is the result of a single-event upset (SEU) in the memory and it is generated during the inversion of the state of...
With the event of nanoscale technologies, new physical phenomena and technological limitations are increasing the process variability and its impact on circuit yield and performances. Like combinatory cells, the sequential cells also suffer of variations, impacting their timing characteristics. Regarding the timing behaviors, setup and hold time violation probabilities are increasing. This article...
Timing-error detection and recovery circuits are implemented in a 65 nm resilient circuit test-chip to eliminate the clock frequency guardband from dynamic supply voltage (VCC) and temperature variations as well as to exploit path-activation probabilities for maximizing throughput. Two error-detection sequential (EDS) circuits are introduced to preserve the timing-error detection capability of previous...
This paper studies the impact of intra-die random variability on low-power digital circuit designs, specifically, circuit timing failures due to intra-die variability. We identify a new low-Vdd statistical failure mode that is strongly supply-voltage dependent and also introduce a simple yet novel method for quantifying the effects of process variability on digital timing - a delay overlapping stage...
This paper describes a design flow for the circuit-level optimization of a technology. The concurrent exploration of device characteristics and library design choices leads to a more application-optimal technology. We illustrate the design flow by: 1) analyzing the impact of buffer cell design, and 2) by optimizing a 130 nm technology for low operational power.
We present a generic method for analyzing the effect of process variability in nanoscale circuits. The proposed framework uses kernel and a generic tail probability estimator to eliminate the need for a-priori density choice for the nature of circuit variation. This allows capturing the true nature of the circuit variation from a few random samples of its observed responses. The data-driven, non-parametric,...
The dramatic increase in leakage current, coupled with the swell in process variability in nano-scaled CMOS technologies, has become a major issue for future IC design. Moreover, due to the spread of leakage power values, leakage variability cannot be neglected anymore. In this work an accurate analytic estimation and modeling methodology has been developed for logic gates leakage under statistical...
A high bandwidth critical path monitor (1 sample/ cycle at 4-5 GHz) capable of providing real-time timing margin information to a variable voltage/frequency scaling control loop is described. The critical path monitor tracks the critical path delay to within 1 FO2 inverter delay with a standard deviation less than 3 FO2 delays over process, voltage, temperature, and workload. The CPM is sensitive...
A circuit for on-chip measurement of long-term jitter, period jitter, and clock skew, is demonstrated. The circuit uses a single latch and a voltage-controlled delay element, and is evaluated in a stand-alone pad frame. Excellent reproduction of jitter measured by oscilloscope is shown. Measured jitter resolution is 1 ps or better. The circuit is also incorporated into a 2 GHz clock distribution network...
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