The document discusses minimizing crosstalk in VLSI routing. It begins with an overview of routing and discusses global routing versus detailed routing. It then covers crosstalk effects, including inductive and capacitive coupling between wires. Approaches to avoid crosstalk include segregating wires, increasing spacing, assigning wires to different layers, and estimating and minimizing crosstalk during routing. Techniques for detailed routing include net ordering, layer assignment, and rip-up and reroute to meet crosstalk constraints.
This document summarizes techniques for minimizing crosstalk in VLSI designs. It discusses the VLSI design cycle and physical design cycle. Routing is a key stage that involves global and detailed routing. Crosstalk occurs due to mutual inductance and capacitance between wires and can affect signal integrity, delay, and timing. Basic approaches to reduce crosstalk include segregating wires, increasing spacing between wires, using ground shields, optimizing the net ordering and layer assignments. Specific techniques mentioned are widening spacing, minimizing wire heights and lengths of parallel runs, using differential routing, and routing orthogonal layers.
This document discusses ASIC placement, which involves assigning exact locations to circuit components within a chip's core area. The goals of placement are to minimize the total interconnect length and costs while meeting timing requirements. It describes two main placement techniques - global placement, which groups cells to minimize interconnect between groups, and detailed placement, which further optimizes placement objectives. The document outlines various placement algorithms, goals, and trends like mixed-size placement and whitespace distribution to improve routability and performance.
Power gating is the main power reduction techniques for the static power. As long as technology scaling is taking place, static power becomes paramount important factor to the VLSI designs.Therefore Power gating is the recent power reduction technique that is actively in research areas.
This document discusses double patterning lithography techniques. It introduces how optical lithography is approaching its limits and double patterning is needed for smaller feature sizes. It describes the double patterning process and challenges including feature distortion and decreased yield. The document outlines techniques for polygon cutting, priority search trees, and decomposing conflict graphs into tri-connected components to solve the layout splitting problem. Experimental results on test cases including a 320k polygon design show the method achieves 3-10x speedup.
Define Width and Height of Core and Die (http://www.vlsisystemdesign.com/PD-F...VLSI SYSTEM Design
https://www.udemy.com/vlsi-academy
The very first step in chip design is floorplanning, in which the width and height of the chip, basically the area of the chip, is defined. A chip consists of two parts, 'core' and 'die'.
The physical design flow begins with placement which involves assigning exact locations to modules like gates and standard cells to minimize area and interconnect cost while meeting timing constraints, with the goal of enabling easier routing; placement tools take as input the netlist, floorplan, libraries, and constraints to perform global and detailed placement as well as optimization. The quality of placement significantly impacts the ability to route the design successfully.
Crosstalk occurs when signals on adjacent wires capacitively couple, causing unwanted noise or delay. As technology scales down, coupling capacitance increases relative to self capacitance, leading to more crosstalk. There are two types of crosstalk: noise crosstalk causes glitches on idle nets, while delay crosstalk impacts timing margins. Methods to reduce crosstalk include decreasing the aggressor net's drive strength, increasing the victim's drive strength, adding shields between nets, and using buffers with hysteresis.
This document summarizes techniques for minimizing crosstalk in VLSI designs. It discusses the VLSI design cycle and physical design cycle. Routing is a key stage that involves global and detailed routing. Crosstalk occurs due to mutual inductance and capacitance between wires and can affect signal integrity, delay, and timing. Basic approaches to reduce crosstalk include segregating wires, increasing spacing between wires, using ground shields, optimizing the net ordering and layer assignments. Specific techniques mentioned are widening spacing, minimizing wire heights and lengths of parallel runs, using differential routing, and routing orthogonal layers.
This document discusses ASIC placement, which involves assigning exact locations to circuit components within a chip's core area. The goals of placement are to minimize the total interconnect length and costs while meeting timing requirements. It describes two main placement techniques - global placement, which groups cells to minimize interconnect between groups, and detailed placement, which further optimizes placement objectives. The document outlines various placement algorithms, goals, and trends like mixed-size placement and whitespace distribution to improve routability and performance.
Power gating is the main power reduction techniques for the static power. As long as technology scaling is taking place, static power becomes paramount important factor to the VLSI designs.Therefore Power gating is the recent power reduction technique that is actively in research areas.
This document discusses double patterning lithography techniques. It introduces how optical lithography is approaching its limits and double patterning is needed for smaller feature sizes. It describes the double patterning process and challenges including feature distortion and decreased yield. The document outlines techniques for polygon cutting, priority search trees, and decomposing conflict graphs into tri-connected components to solve the layout splitting problem. Experimental results on test cases including a 320k polygon design show the method achieves 3-10x speedup.
Define Width and Height of Core and Die (http://www.vlsisystemdesign.com/PD-F...VLSI SYSTEM Design
https://www.udemy.com/vlsi-academy
The very first step in chip design is floorplanning, in which the width and height of the chip, basically the area of the chip, is defined. A chip consists of two parts, 'core' and 'die'.
The physical design flow begins with placement which involves assigning exact locations to modules like gates and standard cells to minimize area and interconnect cost while meeting timing constraints, with the goal of enabling easier routing; placement tools take as input the netlist, floorplan, libraries, and constraints to perform global and detailed placement as well as optimization. The quality of placement significantly impacts the ability to route the design successfully.
Crosstalk occurs when signals on adjacent wires capacitively couple, causing unwanted noise or delay. As technology scales down, coupling capacitance increases relative to self capacitance, leading to more crosstalk. There are two types of crosstalk: noise crosstalk causes glitches on idle nets, while delay crosstalk impacts timing margins. Methods to reduce crosstalk include decreasing the aggressor net's drive strength, increasing the victim's drive strength, adding shields between nets, and using buffers with hysteresis.
As we push through lower technology nodes in the IC and chip design, the wire width goes thinner along with transistor size. This makes the wire resistance more dominant on 16nm and below technology nodes. This increasing resistance and the decreasing width of metal wires introduce many Electromigration and IR drop issues. These two issues play major roles in reducing the lifespan of an electronic device and are the causes of functionality failure in any electronic devices with lower technology nodes.
In this article, we will discuss the problems of electromigration and IR drop, and techniques to prevent the occurrence of these issues in electronic devices.
Electromigration is the gradual displacement of metal atoms in a semiconductor. It occurs when the current density is high enough to cause the drift of metal ions in the direction of the electron flow, and is characterized by the ion flux density. This density depends on the magnitude of forces that tend to hold the ions in place, i.e., the nature of the conductor, crystal size, interface and grain-boundary chemistry, and the magnitude of forces that tend to dislodge them, including the current density, temperature and mechanical stresses.
The Power supply in the chip is distributed uniformly through metal layers (Vdd & Vss) across the design. These metal layers have finite amount of resistance. When voltage is applied to this metal wires current starts flowing through the metal layers and some voltage is dropped due to that resistance of metal wires and current. this drop is called as IR drop.
This document discusses various low power techniques for integrated circuits. It begins by describing the increasing challenges of power consumption as device densities and clock frequencies increase while supply voltages and threshold voltages decrease. It then discusses different types of power consumption, including dynamic power, static power, leakage power from different sources, and how they can be reduced. The document covers many low power design techniques like multi-threshold CMOS, clock gating, multi-voltage, DVFS, and more. It discusses the evolution of these techniques and challenges in their implementation like timing issues, level shifters, and floorplanning for multi-voltage designs.
Physical design involves taking a synthesized netlist as input and performing floorplanning, placement, and routing to produce a physical layout. Key inputs include the netlist, timing constraints, physical libraries, and technology files. The process involves floor planning to determine block placement and routing areas, power planning to create the power distribution network, and pre-routing of standard cells and power grids. The goal is to meet timing constraints while minimizing area.
This document discusses the layout of analog CMOS integrated circuits. It focuses on the layout of transistors and basic cells. Key topics covered include:
- Layout of a single transistor, use of multiple fingers, and interdigitated transistors for matching.
- Common centroid layouts and dummy devices to reduce mismatch.
- Ensuring matched interconnect resistance, capacitance, and parasitics.
- Stacked layout of analog cells with stick diagrams to represent multiple transistors.
- Two examples of laying out basic cells - a two-stage op-amp and folded cascode. Design considerations like transistor sizing and grouping are discussed.
https://www.udemy.com/vlsi-academy
Usually, while drawing any circuit on paper, we have only one 'vdd' at the top and one 'vss' at the bottom. But on a chip, it becomes necessary to have a grid structure of power, with more than one 'vdd' and 'vss'. The concept of power grid structure would be uploaded soon. It is actually the scaling trend that drives chip designers for power grid structure.
This document discusses multi mode multi corner (MMMC) analysis for chip design. It defines that a mode is a set of design parameters like clocks and timing constraints, and a corner captures process, voltage, and temperature variations. It provides examples of multiple modes like normal, sleep, and test modes and corners for temperature, voltage, process variations, and parasitic interconnects. The document gives an example of analyzing a chip with 4 modes under 3 process-voltage-temperature corners and 3 parasitic interconnect corners, showing 9 analysis cases.
Routing in Integrated circuits is an important task which requires extreme care while placing the modules and circuits and connecting them with each other.
The document discusses four topics related to transistors:
1. Threshold voltage is the minimum gate voltage needed to create a conducting path between source and drain, and depends on oxide thickness, temperature, and random dopant fluctuations.
2. Latchup refers to a short circuit formed between power and ground rails in an integrated circuit, caused by interaction between parasitic bipolar transistors.
3. Electromigration is the forced movement of metal ions due to an electric field, with atoms traveling toward the positive conductor end and vacancies toward the negative end.
4. Mobility degradation occurs due to lateral and vertical electric fields scattering carriers, reducing surface mobility as channel lengths shrink.
The document discusses placement in physical design. It describes placement as assigning positions to predesigned cells on a chip without overlapping to optimize objectives like minimizing area and interconnects. It discusses different placement types, formulates the placement problem, and describes algorithms like partitioning-based placement, simulated annealing placement, and iterative placement methods.
Fusion Compiler is the next-generation RTL-to-GDSII implementation system architected to address the complexities of advanced node designs and deliver up to 20% improved PPA while reducing Time To Results (TTR) by 2X.
Latch-up occurs in CMOS chips due to the interaction of parasitic bipolar transistors that form a silicon-controlled rectifier between the power and ground rails. This can cause excessive currents and potentially damage devices. Latch-up can be triggered by disturbances that increase the collector current of one of the parasitic transistors, activating positive feedback between the transistors. Guidelines for preventing latch-up include using guard rings connected to power and ground around transistors to reduce resistance and capture minority carriers, as well as placing wells and substrate contacts close to transistor sources.
Clock tree synthesis log messages provide information about:
1) Preprocessing steps like design updates, buffer characterization, and clock tree constraints.
2) The clock tree synthesis process which includes clustering, meeting timing targets, and reporting results.
3) Post processing steps like embedded clock tree optimization, DRC fixing, and placement legalization.
This document introduces VLSI physical design. It discusses how the number of transistors on chips has rapidly increased over time, from 100,000 to over 3 million. Complex chip design is now only possible using computer-aided design tools. The document outlines the different levels of abstraction in chip design from behavioral modeling down to the cell/mask level. It provides examples of logical and architectural design, and discusses the different layout styles including full-custom, gate-array, and standard-cell approaches.
This document provides an overview of an "Analog VLSI Design" course. The goals of the course are to introduce principles of analog integrated circuit design and CMOS technology. Students will learn about CMOS layout design using CAD tools and complete a design project. The course covers topics including CMOS technology, resistors, capacitors, MOSFETs, current mirrors, amplifiers, and data converters. Assessment includes homework, a project, and a final exam.
The document discusses various aspects of physical design in VLSI circuits. It describes the physical design cycle which involves transforming a circuit diagram into a layout through steps like partitioning, floorplanning, placement, routing, and compaction. It also discusses different design styles like full-custom, standard cell, and gate array. Full-custom design allows maximum flexibility but has higher complexity, while restricted models like standard cell and gate array simplify the design process at the cost of less optimization in the layout. Physical design aims to produce layouts that meet timing and area constraints.
The document discusses several key challenges in physical design for semiconductor chips. It outlines general challenges faced in analog, digital, and mixed-signal design such as manufacturing technology limitations, leakage power, interconnect delay, and congestion. Specific issues discussed in more detail include routing congestion, IR drop causing voltage variations, crosstalk interference, scaling challenges between different process nodes, and thermal issues in 3D chip design involving through-silicon vias. The document provides an overview of design objectives to optimize power, timing, area, and yield against these physical implementation challenges.
This document discusses engineering change orders (ECOs) used to fix timing, functional, power, and clock issues after physical design and sign-off. It describes the motivation for ECOs due to tool limitations and differences between implementation and sign-off. Common ECO techniques are listed for timing (driver upsizing, buffer insertion, etc.), power (vt-swapping, downsizing, etc.), and metal-only ECOs. Timing ECO tools from Synopsys, Cadence, and other vendors are also mentioned. Upcoming ECO technologies like dynamic power optimization and automatic legalization are noted.
This is the presentation that was shared by Nilesh Ranpura and Vineeth Mathramkote at CDNLIVE 2015. The session briefs about the implementation challenges and covers the solution approach and how to achieve results
This document discusses the design of high performance printed circuit boards. It covers topics such as PCB design flow, mechanical design considerations, electrical considerations like impedance and noise, capacitor advantages and disadvantages, microstrip and signal trace configurations, cross-talk control techniques, termination methods, and guidelines for layout and EMI reduction. The goal is to minimize delays, noise, and reliability issues through careful mechanical and electrical design.
This document discusses signal integrity issues in digital systems. It covers topics like reflections, crosstalk, transmission line characteristics, eye diagrams and analysis tools. Reflections can cause problems like ringing at interconnect boundaries due to impedance mismatches. Crosstalk is unwanted coupling between signal lines and can reduce noise margins. Transmission lines are characterized by parameters like impedance and delay. Eye diagrams are used to analyze signal quality by superimposing waveforms. Analysis tools include oscilloscopes, TDR and simulating eye diagrams with long pseudorandom bit sequences. Maintaining signal integrity requires careful design of transmission line structures, termination, limiting crosstalk and avoiding interference between symbols.
As we push through lower technology nodes in the IC and chip design, the wire width goes thinner along with transistor size. This makes the wire resistance more dominant on 16nm and below technology nodes. This increasing resistance and the decreasing width of metal wires introduce many Electromigration and IR drop issues. These two issues play major roles in reducing the lifespan of an electronic device and are the causes of functionality failure in any electronic devices with lower technology nodes.
In this article, we will discuss the problems of electromigration and IR drop, and techniques to prevent the occurrence of these issues in electronic devices.
Electromigration is the gradual displacement of metal atoms in a semiconductor. It occurs when the current density is high enough to cause the drift of metal ions in the direction of the electron flow, and is characterized by the ion flux density. This density depends on the magnitude of forces that tend to hold the ions in place, i.e., the nature of the conductor, crystal size, interface and grain-boundary chemistry, and the magnitude of forces that tend to dislodge them, including the current density, temperature and mechanical stresses.
The Power supply in the chip is distributed uniformly through metal layers (Vdd & Vss) across the design. These metal layers have finite amount of resistance. When voltage is applied to this metal wires current starts flowing through the metal layers and some voltage is dropped due to that resistance of metal wires and current. this drop is called as IR drop.
This document discusses various low power techniques for integrated circuits. It begins by describing the increasing challenges of power consumption as device densities and clock frequencies increase while supply voltages and threshold voltages decrease. It then discusses different types of power consumption, including dynamic power, static power, leakage power from different sources, and how they can be reduced. The document covers many low power design techniques like multi-threshold CMOS, clock gating, multi-voltage, DVFS, and more. It discusses the evolution of these techniques and challenges in their implementation like timing issues, level shifters, and floorplanning for multi-voltage designs.
Physical design involves taking a synthesized netlist as input and performing floorplanning, placement, and routing to produce a physical layout. Key inputs include the netlist, timing constraints, physical libraries, and technology files. The process involves floor planning to determine block placement and routing areas, power planning to create the power distribution network, and pre-routing of standard cells and power grids. The goal is to meet timing constraints while minimizing area.
This document discusses the layout of analog CMOS integrated circuits. It focuses on the layout of transistors and basic cells. Key topics covered include:
- Layout of a single transistor, use of multiple fingers, and interdigitated transistors for matching.
- Common centroid layouts and dummy devices to reduce mismatch.
- Ensuring matched interconnect resistance, capacitance, and parasitics.
- Stacked layout of analog cells with stick diagrams to represent multiple transistors.
- Two examples of laying out basic cells - a two-stage op-amp and folded cascode. Design considerations like transistor sizing and grouping are discussed.
https://www.udemy.com/vlsi-academy
Usually, while drawing any circuit on paper, we have only one 'vdd' at the top and one 'vss' at the bottom. But on a chip, it becomes necessary to have a grid structure of power, with more than one 'vdd' and 'vss'. The concept of power grid structure would be uploaded soon. It is actually the scaling trend that drives chip designers for power grid structure.
This document discusses multi mode multi corner (MMMC) analysis for chip design. It defines that a mode is a set of design parameters like clocks and timing constraints, and a corner captures process, voltage, and temperature variations. It provides examples of multiple modes like normal, sleep, and test modes and corners for temperature, voltage, process variations, and parasitic interconnects. The document gives an example of analyzing a chip with 4 modes under 3 process-voltage-temperature corners and 3 parasitic interconnect corners, showing 9 analysis cases.
Routing in Integrated circuits is an important task which requires extreme care while placing the modules and circuits and connecting them with each other.
The document discusses four topics related to transistors:
1. Threshold voltage is the minimum gate voltage needed to create a conducting path between source and drain, and depends on oxide thickness, temperature, and random dopant fluctuations.
2. Latchup refers to a short circuit formed between power and ground rails in an integrated circuit, caused by interaction between parasitic bipolar transistors.
3. Electromigration is the forced movement of metal ions due to an electric field, with atoms traveling toward the positive conductor end and vacancies toward the negative end.
4. Mobility degradation occurs due to lateral and vertical electric fields scattering carriers, reducing surface mobility as channel lengths shrink.
The document discusses placement in physical design. It describes placement as assigning positions to predesigned cells on a chip without overlapping to optimize objectives like minimizing area and interconnects. It discusses different placement types, formulates the placement problem, and describes algorithms like partitioning-based placement, simulated annealing placement, and iterative placement methods.
Fusion Compiler is the next-generation RTL-to-GDSII implementation system architected to address the complexities of advanced node designs and deliver up to 20% improved PPA while reducing Time To Results (TTR) by 2X.
Latch-up occurs in CMOS chips due to the interaction of parasitic bipolar transistors that form a silicon-controlled rectifier between the power and ground rails. This can cause excessive currents and potentially damage devices. Latch-up can be triggered by disturbances that increase the collector current of one of the parasitic transistors, activating positive feedback between the transistors. Guidelines for preventing latch-up include using guard rings connected to power and ground around transistors to reduce resistance and capture minority carriers, as well as placing wells and substrate contacts close to transistor sources.
Clock tree synthesis log messages provide information about:
1) Preprocessing steps like design updates, buffer characterization, and clock tree constraints.
2) The clock tree synthesis process which includes clustering, meeting timing targets, and reporting results.
3) Post processing steps like embedded clock tree optimization, DRC fixing, and placement legalization.
This document introduces VLSI physical design. It discusses how the number of transistors on chips has rapidly increased over time, from 100,000 to over 3 million. Complex chip design is now only possible using computer-aided design tools. The document outlines the different levels of abstraction in chip design from behavioral modeling down to the cell/mask level. It provides examples of logical and architectural design, and discusses the different layout styles including full-custom, gate-array, and standard-cell approaches.
This document provides an overview of an "Analog VLSI Design" course. The goals of the course are to introduce principles of analog integrated circuit design and CMOS technology. Students will learn about CMOS layout design using CAD tools and complete a design project. The course covers topics including CMOS technology, resistors, capacitors, MOSFETs, current mirrors, amplifiers, and data converters. Assessment includes homework, a project, and a final exam.
The document discusses various aspects of physical design in VLSI circuits. It describes the physical design cycle which involves transforming a circuit diagram into a layout through steps like partitioning, floorplanning, placement, routing, and compaction. It also discusses different design styles like full-custom, standard cell, and gate array. Full-custom design allows maximum flexibility but has higher complexity, while restricted models like standard cell and gate array simplify the design process at the cost of less optimization in the layout. Physical design aims to produce layouts that meet timing and area constraints.
The document discusses several key challenges in physical design for semiconductor chips. It outlines general challenges faced in analog, digital, and mixed-signal design such as manufacturing technology limitations, leakage power, interconnect delay, and congestion. Specific issues discussed in more detail include routing congestion, IR drop causing voltage variations, crosstalk interference, scaling challenges between different process nodes, and thermal issues in 3D chip design involving through-silicon vias. The document provides an overview of design objectives to optimize power, timing, area, and yield against these physical implementation challenges.
This document discusses engineering change orders (ECOs) used to fix timing, functional, power, and clock issues after physical design and sign-off. It describes the motivation for ECOs due to tool limitations and differences between implementation and sign-off. Common ECO techniques are listed for timing (driver upsizing, buffer insertion, etc.), power (vt-swapping, downsizing, etc.), and metal-only ECOs. Timing ECO tools from Synopsys, Cadence, and other vendors are also mentioned. Upcoming ECO technologies like dynamic power optimization and automatic legalization are noted.
This is the presentation that was shared by Nilesh Ranpura and Vineeth Mathramkote at CDNLIVE 2015. The session briefs about the implementation challenges and covers the solution approach and how to achieve results
This document discusses the design of high performance printed circuit boards. It covers topics such as PCB design flow, mechanical design considerations, electrical considerations like impedance and noise, capacitor advantages and disadvantages, microstrip and signal trace configurations, cross-talk control techniques, termination methods, and guidelines for layout and EMI reduction. The goal is to minimize delays, noise, and reliability issues through careful mechanical and electrical design.
This document discusses signal integrity issues in digital systems. It covers topics like reflections, crosstalk, transmission line characteristics, eye diagrams and analysis tools. Reflections can cause problems like ringing at interconnect boundaries due to impedance mismatches. Crosstalk is unwanted coupling between signal lines and can reduce noise margins. Transmission lines are characterized by parameters like impedance and delay. Eye diagrams are used to analyze signal quality by superimposing waveforms. Analysis tools include oscilloscopes, TDR and simulating eye diagrams with long pseudorandom bit sequences. Maintaining signal integrity requires careful design of transmission line structures, termination, limiting crosstalk and avoiding interference between symbols.
This document discusses transmission line theory and how to determine if a circuit requires transmission line analysis. It explains that if the length of an interconnect is greater than one tenth of a signal's wavelength, or if a signal's rise time is less than twice the propagation delay time, transmission line effects need to be considered. The document provides formulas for calculating characteristic impedance of transmission lines and discusses various termination techniques like series, parallel, and Thevenin terminations to prevent reflections on transmission lines.
This document discusses different interconnect timing models used to model delays caused by interconnects in integrated circuits. It describes lumped capacitor, transmission line, lumped RC, Elmore delay, distributed RC, and RLC models. The lumped capacitor and transmission line models treat interconnects as either purely capacitive or propagating waves, while the lumped RC, distributed RC, and RLC models account for resistive and inductive effects at higher frequencies. The Elmore delay model provides a simplified yet accurate way to calculate delays in RC networks. Overall, the choice of timing model depends on factors like the operating frequency and interconnect geometry.
Terminators are used to reduce unwanted signal reflections on transmission lines. There are two main cases where terminators are needed: 1) for long lines where the cable length exceeds 1/6 of the signal rise time and 2) for short, capacitively loaded lines. There are different types of terminators including end, source, and middle terminators. End terminators locate the terminating resistor at the receiving end to dampen reflections, while source terminators use a series resistor at the driving end. Middle terminators can be used to reduce reflections in complex networks without defined sources or destinations. Proper terminator selection and placement is needed to minimize reflections based on transmission line characteristics and circuit configurations.
Popular Interview Wireless Question with AnswerVARUN KUMAR
Favourable propagation refers to the orthogonality among vector-valued wireless channels that can maximize total system throughput. It occurs when the interference terms in the channel capacity equation, which involve the product of different channel coefficients, approach zero. Time division duplexing (TDD) is more complex than frequency division duplexing (FDD) due to hardware mismatches across base stations and user equipment for uplink and downlink channels. Channel reciprocity can be achieved through FDD if the uplink and downlink carrier frequencies are nearly equal, but not if they are significantly different.
This document provides an overview of transmission line basics and concepts. It discusses key transmission line parameters like characteristic impedance, propagation delay, per-unit-length capacitance and inductance. It covers transmission line equivalent circuit models and relevant equations. It also discusses transmission line structures, parallel plate approximations, reflection coefficients, and discontinuities. The goal is to understand transmission line behavior and analysis techniques.
This document discusses various wireless propagation channels including free space propagation, reflection, scattering, and diffraction. It covers reflection propagation mechanisms such as reflection from dielectrics and conductors. Reflection coefficients and Snell's law are explained. Models for reflection, including the two-ray ground reflection model, are provided. Diffraction models like knife-edge diffraction and multiple knife-edge diffraction using methods like Bollington's method are summarized. Scattering models including Kirchoff's theory and perturbation theory are covered. Common fading models for mobile radio like Rayleigh, Rician, and Doppler shift models are described. Finally, different types of wireless channels including time-selective, frequency-selective, general, and WSSUS channels are classified
This document summarizes cable characteristics related to magnetic fields and alternating current. It discusses how a cable carrying current has an associated magnetic field that is not altered by insulation. The magnetic field causes self-inductance in the conductor. Skin effect results in current preferentially flowing in outer parts of the conductor at alternating current frequencies, increasing resistance. Proximity effect similarly alters current distribution between conductors carrying alternating current. Shields and sheaths on cables can experience induced voltages and currents from surrounding conductors, resulting in I2R losses. Formulas are provided for calculating self-inductance, skin effect, proximity effect, induced voltages and currents, and resistance increases.
The document discusses VLSI interconnects and their impact on integrated circuit performance. As technology scales, interconnect delay becomes more dominant compared to gate delay. Interconnects introduce parasitic resistances, capacitances, and inductances that increase propagation delay and power dissipation. Repeater insertion and alternative low-resistance metals like copper can help reduce delay. Emerging technologies like carbon nanotubes have the potential to further improve interconnect performance due to their low resistance and capacitance.
Naveen Kumar's document discusses small-scale fading in mobile wireless channels. It describes the effects of multipath propagation, Doppler shifts from mobility, and how these cause rapid fluctuations in signal strength over small distances and time periods. It also defines several key parameters that characterize mobile multipath channels, including coherence bandwidth, Doppler spread, coherence time, delay spread, and excess delay spread. These parameters quantify the time-dispersive and time-varying nature of wireless channels.
1) The document discusses small-scale fading in mobile radio channels caused by multipath propagation. Multipath signals interfere constructively and destructively, causing rapid fluctuations in received signal strength over small distances.
2) Key parameters that characterize multipath channels are delay spread (στ), coherence bandwidth (Bc), Doppler spread (BD), and coherence time (Tc). Delay spread and coherence bandwidth describe time dispersion, while Doppler spread and coherence time describe frequency dispersion from mobility.
3) There are different types of fading depending on how a signal's bandwidth compares to these channel parameters. Flat fading occurs when the signal bandwidth is narrow compared to the channel bandwidth, preserving the signal's spectral properties.
The document summarizes the design and analysis of microstrip patch antennas. It describes the basic structure of a microstrip patch antenna consisting of a radiating patch on top of a dielectric substrate with a ground plane on the bottom. It discusses various parameters that affect the antenna performance such as the length and width of the patch, substrate thickness and dielectric constant. The document also covers different analysis techniques, feeding methods, use of Smith chart for impedance matching, and parametric analysis to study the effect of variables on input impedance and bandwidth.
An engineer told the document author that the measured clock signal was non-monotonic, which could cause the flip flop internally to double clock the data. The goal of the document is to determine the cause of the non-monotonic clock by inspecting it, and determine if it poses a problem. The document covers transmission line concepts including equivalent circuits, reflection diagrams, termination methods, and propagation delay. It provides equations for characteristic impedance, propagation, and reflection coefficient. Formulas for microstrip, stripline, and their parameters like capacitance and inductance are also presented.
Signal Integrity - A Crash Course [R Lott]Ryan Lott
This document provides an introduction to signal integrity for interconnects. It discusses typical interconnects like PCB traces, cables, and connectors and the signal integrity problems they can cause, such as loss, reflections, crosstalk, and ringing. It also introduces concepts like characteristic impedance, frequency-dependent loss, and how signals propagate as electromagnetic waves. Measurement techniques like S-parameters and using a vector network analyzer are discussed as ways to characterize devices in the frequency domain.
This document discusses the importance of signal integrity simulations for PCB design. It emphasizes that simulations provide solutions to improve performance and reduce costs when done with the right metrics and models. Case studies show how simulations can determine if certain design choices like termination resistors or microstrip vs stripline routing are needed. Good metrics for analysis include noise margin, timing margin, and waveform characteristics. Accurate models of transmission lines, I/O buffers, and packages are also key to get reliable simulation results.
This document discusses the importance of signal integrity simulations for PCB design. It emphasizes that simulations provide solutions to improve performance and reduce costs when done with the right metrics and quality models. Case studies demonstrate how simulations can show that expensive clock termination is not needed for a design or that stripline routing has too much crosstalk compared to microstrip. Good simulations rely on metrics like noise margin and timing margin to analyze waveforms as well as accurate transmission line and I/O buffer models.
Similar to minimisation of crosstalk in VLSI routing (20)
Observability Concepts EVERY Developer Should Know -- DeveloperWeek Europe.pdfPaige Cruz
Monitoring and observability aren’t traditionally found in software curriculums and many of us cobble this knowledge together from whatever vendor or ecosystem we were first introduced to and whatever is a part of your current company’s observability stack.
While the dev and ops silo continues to crumble….many organizations still relegate monitoring & observability as the purview of ops, infra and SRE teams. This is a mistake - achieving a highly observable system requires collaboration up and down the stack.
I, a former op, would like to extend an invitation to all application developers to join the observability party will share these foundational concepts to build on:
Removing Uninteresting Bytes in Software FuzzingAftab Hussain
Imagine a world where software fuzzing, the process of mutating bytes in test seeds to uncover hidden and erroneous program behaviors, becomes faster and more effective. A lot depends on the initial seeds, which can significantly dictate the trajectory of a fuzzing campaign, particularly in terms of how long it takes to uncover interesting behaviour in your code. We introduce DIAR, a technique designed to speedup fuzzing campaigns by pinpointing and eliminating those uninteresting bytes in the seeds. Picture this: instead of wasting valuable resources on meaningless mutations in large, bloated seeds, DIAR removes the unnecessary bytes, streamlining the entire process.
In this work, we equipped AFL, a popular fuzzer, with DIAR and examined two critical Linux libraries -- Libxml's xmllint, a tool for parsing xml documents, and Binutil's readelf, an essential debugging and security analysis command-line tool used to display detailed information about ELF (Executable and Linkable Format). Our preliminary results show that AFL+DIAR does not only discover new paths more quickly but also achieves higher coverage overall. This work thus showcases how starting with lean and optimized seeds can lead to faster, more comprehensive fuzzing campaigns -- and DIAR helps you find such seeds.
- These are slides of the talk given at IEEE International Conference on Software Testing Verification and Validation Workshop, ICSTW 2022.
GraphSummit Singapore | The Art of the Possible with Graph - Q2 2024Neo4j
Neha Bajwa, Vice President of Product Marketing, Neo4j
Join us as we explore breakthrough innovations enabled by interconnected data and AI. Discover firsthand how organizations use relationships in data to uncover contextual insights and solve our most pressing challenges – from optimizing supply chains, detecting fraud, and improving customer experiences to accelerating drug discoveries.
In his public lecture, Christian Timmerer provides insights into the fascinating history of video streaming, starting from its humble beginnings before YouTube to the groundbreaking technologies that now dominate platforms like Netflix and ORF ON. Timmerer also presents provocative contributions of his own that have significantly influenced the industry. He concludes by looking at future challenges and invites the audience to join in a discussion.
Driving Business Innovation: Latest Generative AI Advancements & Success StorySafe Software
Are you ready to revolutionize how you handle data? Join us for a webinar where we’ll bring you up to speed with the latest advancements in Generative AI technology and discover how leveraging FME with tools from giants like Google Gemini, Amazon, and Microsoft OpenAI can supercharge your workflow efficiency.
During the hour, we’ll take you through:
Guest Speaker Segment with Hannah Barrington: Dive into the world of dynamic real estate marketing with Hannah, the Marketing Manager at Workspace Group. Hear firsthand how their team generates engaging descriptions for thousands of office units by integrating diverse data sources—from PDF floorplans to web pages—using FME transformers, like OpenAIVisionConnector and AnthropicVisionConnector. This use case will show you how GenAI can streamline content creation for marketing across the board.
Ollama Use Case: Learn how Scenario Specialist Dmitri Bagh has utilized Ollama within FME to input data, create custom models, and enhance security protocols. This segment will include demos to illustrate the full capabilities of FME in AI-driven processes.
Custom AI Models: Discover how to leverage FME to build personalized AI models using your data. Whether it’s populating a model with local data for added security or integrating public AI tools, find out how FME facilitates a versatile and secure approach to AI.
We’ll wrap up with a live Q&A session where you can engage with our experts on your specific use cases, and learn more about optimizing your data workflows with AI.
This webinar is ideal for professionals seeking to harness the power of AI within their data management systems while ensuring high levels of customization and security. Whether you're a novice or an expert, gain actionable insights and strategies to elevate your data processes. Join us to see how FME and AI can revolutionize how you work with data!
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HCL Notes und Domino Lizenzkostenreduzierung in der Welt von DLAUpanagenda
Webinar Recording: https://www.panagenda.com/webinars/hcl-notes-und-domino-lizenzkostenreduzierung-in-der-welt-von-dlau/
DLAU und die Lizenzen nach dem CCB- und CCX-Modell sind für viele in der HCL-Community seit letztem Jahr ein heißes Thema. Als Notes- oder Domino-Kunde haben Sie vielleicht mit unerwartet hohen Benutzerzahlen und Lizenzgebühren zu kämpfen. Sie fragen sich vielleicht, wie diese neue Art der Lizenzierung funktioniert und welchen Nutzen sie Ihnen bringt. Vor allem wollen Sie sicherlich Ihr Budget einhalten und Kosten sparen, wo immer möglich. Das verstehen wir und wir möchten Ihnen dabei helfen!
Wir erklären Ihnen, wie Sie häufige Konfigurationsprobleme lösen können, die dazu führen können, dass mehr Benutzer gezählt werden als nötig, und wie Sie überflüssige oder ungenutzte Konten identifizieren und entfernen können, um Geld zu sparen. Es gibt auch einige Ansätze, die zu unnötigen Ausgaben führen können, z. B. wenn ein Personendokument anstelle eines Mail-Ins für geteilte Mailboxen verwendet wird. Wir zeigen Ihnen solche Fälle und deren Lösungen. Und natürlich erklären wir Ihnen das neue Lizenzmodell.
Nehmen Sie an diesem Webinar teil, bei dem HCL-Ambassador Marc Thomas und Gastredner Franz Walder Ihnen diese neue Welt näherbringen. Es vermittelt Ihnen die Tools und das Know-how, um den Überblick zu bewahren. Sie werden in der Lage sein, Ihre Kosten durch eine optimierte Domino-Konfiguration zu reduzieren und auch in Zukunft gering zu halten.
Diese Themen werden behandelt
- Reduzierung der Lizenzkosten durch Auffinden und Beheben von Fehlkonfigurationen und überflüssigen Konten
- Wie funktionieren CCB- und CCX-Lizenzen wirklich?
- Verstehen des DLAU-Tools und wie man es am besten nutzt
- Tipps für häufige Problembereiche, wie z. B. Team-Postfächer, Funktions-/Testbenutzer usw.
- Praxisbeispiele und Best Practices zum sofortigen Umsetzen
Full-RAG: A modern architecture for hyper-personalizationZilliz
Mike Del Balso, CEO & Co-Founder at Tecton, presents "Full RAG," a novel approach to AI recommendation systems, aiming to push beyond the limitations of traditional models through a deep integration of contextual insights and real-time data, leveraging the Retrieval-Augmented Generation architecture. This talk will outline Full RAG's potential to significantly enhance personalization, address engineering challenges such as data management and model training, and introduce data enrichment with reranking as a key solution. Attendees will gain crucial insights into the importance of hyperpersonalization in AI, the capabilities of Full RAG for advanced personalization, and strategies for managing complex data integrations for deploying cutting-edge AI solutions.
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This session provides introduction to UiPath Communication Mining, importance and platform overview. You will acquire a good understand of the phases in Communication Mining as we go over the platform with you. Topics covered:
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• Demo on Platform overview
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3. Index
• ROUTING
• CROSSTALK OVERVIEW
• EFFECTS OF CROSSTALK
• APPROACHES TO AVOID CROSSTALK
• METHODS TO MINIMISE CROSSTALK
• CONCLUSION
• REFERENCES
3
4. Routing
• Problem
Given a placement, and a fixed number of metal
layers, find a valid pattern of horizontal and vertical
wires that connect the terminals of the nets
Levels of abstraction:
Global routing
Detailed routing
• Objectives
Cost components:
1. Area (channel width) – min congestion
2. Wire delays – timing minimization in previous levels
3. Number of layers (fewer layers less expensive)
4. Additional cost components: number of bends, vias
5. Minimisation of crosstalk
4
6. Global vs. Detailed Routing
• Global routing
Input: detailed placement, with exact
terminal locations
Determine “channel” (routing region)
for each net
Objective: minimize area (congestion),
and timing (approximate)
• Detailed routing
Input: channels and approximate
routing from the global routing phase
Determine the exact route and layers
for each net
Objective: valid routing, minimize area
(congestion), meet timing constraints
Additional objectives: min via, power
6
8. Multiple Terminal nets:Steiner Tree
Steiner tree(aka Rectilinear Steiner tree- RST):
A tree connecting multiple terminals.
Original points:”Demand points”- set D.
Added points:”Steiner points”- set S.
Edges horizontal or vertical only.
Steiner Minimum Tree (SMT)
Similar to minimum spanning tree (MST)
– But finding SMT is NP-complete
Many good heuristics introduced to find SMT
Algorithm
1 . Find MST
2 . Pass horizontal and vertical lines from each terminal to
get the Hannan grid (optimal solution is on this grid)
3. Convert each edge of the MST to an L-shaped route
on Hannan grid (add a Steiner point at the corner of L)
8
11. VLSI trends:
– Device size is decreasing.
– Increase the no of transistors, interconnection wires
– Size of the channel is decreased.
Effects:
Increasing coupling effect (inductive & capacitive) between
interconnection wires
Result:
crosstalk
11
13. Mutual Inductance and Capacitance
Crosstalk is the coupling of energy from one line to another via :
Mutual inductance(magnetic field)
Mutual capacitance(electric field)
13
14. Mutual Inductance and Capacitance
Mechanism of coupling
the circuit element representing this transfer of energy are the familiar
equations:
Δ IB= -Cm d(VB - VA) and Δ VB= -Lm dIA
dt dt
Mutual inductance will induce current on the victim line opposite of the driving
current(Lenz’s Law).
14
15. Crosstalk induced noise
The near and far end victim line currents sum to produce the near
and far end crosstalk noise.
Coupled currents:
I near=Icm + I lm I far=Icm - I lm
• Current induced by capacitive coupling goes to both directions
• Current induced by inductive coupling goes opposite to the drive current
15
16. Crosstalk induced noise
“Voltage profile of coupled noise”
• Near end crosstalk is always positive
• currents from Lm and Cm always add and flow into the node.
• For PCB’s far end crosstalk is “usually” negative
• current due to Lm larger than current due to Cm.
• Note that far end crosstalk can be positive.
16
17. Noise: A Key Stopper in Mixed Signal Systems
Skin effect.
Dielectric absorption
17
20. Effects of crosstalk (contd…)
3.Crosstalk can lead to :
- logic faults(especially in dynamic circuits).
- Voltage overshoot(stress,forward biased PN junctions)
4. When noise acts against a normally static signal, it can destroy the
local information carried by the static node in the circuit and
ultimately result in incorrect machine-state stored in a latch.
5.Timing noise
skew(DC component of timing noise).
jitter(AC component of timing noise).
6. EMI and violation of EMC requirements.
20
22. Segregation / Spacing / Ground Shielding (2)
• Segregation : Dividing many
(noisy) and less(quiet) signal
transition wire and merging
group by group.(use with
shielding)
• Spacing : the method that
signal wire to shun each other,
when signal net is close to
each other (routing channel is
not wide)
• Shielding : blocking signal line
with ground line to minimize
signal interference to the other
wire.(ground bounce occurs
and must broaden the ground
line)
22
23. Net Ordering
Net ordering is used for minimize crosstalk-critical region between each lines.
When, long line and long line is close together, crosstalk between them is more
larger than long line and short line. So, we must change the permutation of track
for minimizing crosstalk.
• Left : Unordered
track permutation
• Right : Ordered
track permutation
for minimizing
crosstalk
23
24. Layer Assignment
When using more than 3 layer in channel routing, adjacent signal
wire in same layer results crosstalk. For example, left figure makes
more crosstalk than right.
Layer assignment problem is solved by integer linear programming
or dynamic programming method.
24
25. Various Techniques To Reduce
Crosstalk
The following PCB design techniques can significantly
reduce crosstalk in micro-strip or strip-line layouts:
SOME TECHNIQUES ARE A RULE OF THUMB.
25
26. 1. Widen spacing S between the signallines as much as routing restrictions will allow.
2. Design the transmission line so that the conductor is as close to the ground plane as
possible. This couples the transmission line tightly to the ground plane and helps
decouple it from adjacent signals.
3. Use differential routing techniques where possible, especially for critical nets.
4. Route signals on different layers orthogonal to each other, if there is significant coupling.
5. Minimize parallel run lengths between signals, routing with short parallel sections
and minimize long coupled sections between nets. 26
27. CROSSTALK ESTIMATION
Crosstalk-estimation:
Bounded partitioning:
partitions the X-talk bound of each net into the regions its go
through
Net ordering:
orders the net in each regions to require as few spare track as
possible
27
28. Crosstalk Constraints Global Routing
(CCGR)
• NP-hard problem
• Two stage heuristic approach
– New Steiner tree formulation to minimize the total X-talk.
– X-talk on each net is estimated.
– nets having X-talk violation is then ripped up and re-routed
28
29. 6.Minimum X-talk Steiner tree
Routing graph G={V,E}
Minimized X-talk Extended Global Routing solution for nets 1…. M-1
is given
Place Mth net such that routing topologies for 1 ………. M-1 are kept and
total X-talk is minimized
Rip-Up & Rerouting
If solution violates crosstalk constraints
Rip-up them
Re-route them one net at a time in the order of
decreasing violation
29
30. EXAMPLE
Nets 1,2,3,4, are routed and net 5 is Shortest path root (not
{p1 & p2} c1=2,c2=3,c3=30, feasible): r1=12,r2=20,r3=4,
c4=36,c5=35 r4=0,r5=32
30
33. Crosstalk reduction techniques(contd…)
8. A structure for reducing crosstalk in VLSI circuits :
the empty areas(3) are filled with ground connections(7 & 11) fig2 below
33
34. Conclusion
NP-hard problem.
Many others approaches are available.
Some GA based approaches are very successfully implemented
Optimal Solution are taken because some other constraints are there like
wire length and congestion .
Also add routing of virtex 5 diagonal from whitepaper
34