This report details the design of a two-stage operational amplifier (op-amp) in Cadence. It begins with hand calculations of component parameters. A schematic is plotted and simulated for DC and AC analysis. The initial design does not meet specifications, so component parameters are modified through several iterations until specifications are met. Finally, geometry optimization using Mosek in MATLAB is presented, though long calculation times prevented results. The report demonstrates the op-amp design process from initial calculations through simulation and optimization to meet specifications.
Current sources, current mirrors, and current steering circuits are important components in integrated circuit design for providing stable bias currents. A constant current is first generated and then replicated across the circuit using current mirrors. Current mirrors use identical MOS transistors such that if the gate-source potentials are equal, the drain currents will be equal, allowing the reference current to be copied. There are various types of current mirror circuits that have different advantages and applications. Current can also be steered between paths using multiple current mirrors, with some mirrors acting as current sources and others as current sinks.
This document presents a new CMOS voltage divider based current mirror and compares it to basic and cascode current mirrors. The basic current mirror has limitations like finite output resistance and channel length modulation effects. The cascode current mirror improves output resistance but wastes threshold voltage. The new CMOS voltage divider current mirror uses an NMOS and PMOS transistor voltage divider to bias an NMOS transistor and control the output current. It consumes less power than the basic current mirror and is well-suited for low current biasing applications.
Designed a differential input and single ended output high gain (>= 85 dB) operational amplifier using CMOS 0.35um technology using a single independent current source. The amplifier was also designed to achieve a CMRR (>= 80dB), Average Slew Rate (>= 15 V/us), UGF (>= 15 MHz) & Output Voltage Swing ( >= 1.4V). The maximum power dissipation through the complete circuit including the current source branch was limited to 0.3 mW.
This document outlines the typical design flow for VLSI chips, including: 1) design specification, 2) design entry using schematics or HDL, 3) functional simulation to verify logic, 4) planning placement and routing of components, 5) timing simulation accounting for delays, and 6) fabrication of the final chip design either using full custom or semi-custom methods. The goal is to design and test a chip that meets the specified requirements before manufacturing.
This document describes the design of a low dropout voltage regulator (LDO) circuit. It includes the goals of providing a 3.3V output voltage from a 5V input. The key components of an LDO - pass transistor, error amplifier, and voltage reference - are discussed. Calculations are shown for efficiency, transistor sizes, setting the bias voltage, and sizing additional transistors. A block diagram and final schematic are presented. Post-layout simulations demonstrate the line regulation as the input voltage is changed.
This report details the design of a two-stage operational amplifier (op-amp) in Cadence. It begins with hand calculations of component parameters. A schematic is plotted and simulated for DC and AC analysis. The initial design does not meet specifications, so component parameters are modified through several iterations until specifications are met. Finally, geometry optimization using Mosek in MATLAB is presented, though long calculation times prevented results. The report demonstrates the op-amp design process from initial calculations through simulation and optimization to meet specifications.
Current sources, current mirrors, and current steering circuits are important components in integrated circuit design for providing stable bias currents. A constant current is first generated and then replicated across the circuit using current mirrors. Current mirrors use identical MOS transistors such that if the gate-source potentials are equal, the drain currents will be equal, allowing the reference current to be copied. There are various types of current mirror circuits that have different advantages and applications. Current can also be steered between paths using multiple current mirrors, with some mirrors acting as current sources and others as current sinks.
This document presents a new CMOS voltage divider based current mirror and compares it to basic and cascode current mirrors. The basic current mirror has limitations like finite output resistance and channel length modulation effects. The cascode current mirror improves output resistance but wastes threshold voltage. The new CMOS voltage divider current mirror uses an NMOS and PMOS transistor voltage divider to bias an NMOS transistor and control the output current. It consumes less power than the basic current mirror and is well-suited for low current biasing applications.
Designed a differential input and single ended output high gain (>= 85 dB) operational amplifier using CMOS 0.35um technology using a single independent current source. The amplifier was also designed to achieve a CMRR (>= 80dB), Average Slew Rate (>= 15 V/us), UGF (>= 15 MHz) & Output Voltage Swing ( >= 1.4V). The maximum power dissipation through the complete circuit including the current source branch was limited to 0.3 mW.
This document outlines the typical design flow for VLSI chips, including: 1) design specification, 2) design entry using schematics or HDL, 3) functional simulation to verify logic, 4) planning placement and routing of components, 5) timing simulation accounting for delays, and 6) fabrication of the final chip design either using full custom or semi-custom methods. The goal is to design and test a chip that meets the specified requirements before manufacturing.
This document describes the design of a low dropout voltage regulator (LDO) circuit. It includes the goals of providing a 3.3V output voltage from a 5V input. The key components of an LDO - pass transistor, error amplifier, and voltage reference - are discussed. Calculations are shown for efficiency, transistor sizes, setting the bias voltage, and sizing additional transistors. A block diagram and final schematic are presented. Post-layout simulations demonstrate the line regulation as the input voltage is changed.
Design of a Fully Differential Folded-Cascode Operational AmplifierSteven Ernst, PE
This document summarizes the design of a fully differential operational amplifier and a second-order Butterworth filter using the designed op-amp. The op-amp was designed using a folded-cascode topology to meet specifications across temperature variations. Simulation results showed it met most specifications. A layout was created and tested, matching the schematic performance. A Butterworth biquad filter was also designed using the op-amp, with simulation results showing corner frequencies around the specified 22kHz point across temperatures.
A printed circuit board (PCB) is a non-conductive board that mechanically supports and electrically connects electronic components using copper tracks etched onto laminated sheets. PCBs can be single-sided, double-sided, or multilayer. They were first developed in the 1930s and are used to build circuit board assemblies, with common types including single-sided, double-sided, and multilayer boards.
The document provides an overview of analog layout design. It discusses that analog circuits require careful attention to geometry during layout due to process variations. The analog design flow includes electrical design, physical design involving layout, and fabrication/testing. Key considerations for analog layout include minimizing parasitic resistances and capacitances, reducing noise, and ensuring matching between identical components using techniques like common-centroid layout. Resistors and capacitors must be carefully laid out to minimize non-ideal effects and provide accurate values.
This document describes the implementation of a bandgap reference circuit. It begins by acknowledging those who supported the project. It then provides an abstract stating that bandgap reference circuits are used to generate stable reference voltages and currents on integrated circuits. The main goal of the project was to understand bandgap reference design and limitations, and implement a bandgap reference circuit in a 90nm CMOS technology using CADENCE.
This document compares and contrasts the basic logic cells of the Xilinx LCA and Altera FLEX FPGA architectures. It describes the evolution of the Xilinx CLB from the XC3000 through XC4000 and XC5200, which all utilize LUTs of varying sizes. The Altera FLEX architecture similarly uses a four-input LUT in its basic logic element. Both architectures are based on SRAM programming technology.
The document discusses circuit design processes and stick diagrams. It begins by introducing MOS layers and objectives of understanding stick diagrams, design rules, and layout. It then covers stick diagrams in depth, explaining that they show relative component placement and layer information through color codes as an interface between symbolic circuits and layouts. Examples of stick diagram rules, notations, and common MOS circuits are provided. Finally, it discusses design rules, explaining that they define feature sizes and spacings to interface between circuits and fabrication processes while allowing for manufacturing tolerances.
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.
Of the many ways of implementing opamp in mixed mode VLSI design, two stage design is often preferred. This presentation illustrates the design process. Download for better view as it has animations
The document discusses the structure and operation of MOS transistors. It describes the basic MOS structure which consists of a metal gate separated from a semiconductor substrate by an oxide layer. Applying a voltage to the gate can induce an inversion layer in the semiconductor to form a channel between the source and drain, allowing current to flow. The threshold voltage is the minimum gate voltage required to form an inversion layer. The document discusses n-channel MOSFETs and their characteristics in different regions of operation defined by the gate-source voltage.
This chapter discusses bipolar junction transistors. It describes the basic transistor construction with PNP and NPN types. It explains transistor operation with forward biased base-emitter and reverse biased base-collector junctions. It also discusses currents in transistors including minority and majority carriers. Different transistor configurations - common base, common emitter, and common collector - are presented along with their input/output characteristics and operating regions. Key parameters like alpha, beta, and power dissipation are also covered.
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 provides an introduction to application specific integrated circuits (ASICs). It discusses that ASICs are non-standard integrated circuits designed for a specific application. The document then categorizes ASICs into three types: full-custom ASICs which have fully customized logic and mask layers; semi-custom ASICs which use predesigned logic cells and have some customized mask layers; and programmable ASICs. Within semi-custom ASICs, the document describes standard cell based and gate array based ASICs, focusing on the differences between channeled, channelless, and structured gate arrays.
The document outlines the design procedure for a two-stage operational amplifier (op amp) in CMOS technology. It begins by listing the design inputs and outputs. It then describes the steps in designing a CMOS op amp including determining the topology, compensation method, and transistor sizes. The document provides equations for analyzing key parameters of a two-stage op amp like gain, bandwidth, and common-mode range. It concludes with an example design problem demonstrating how to use the outlined procedure to design an op amp that meets given specifications.
This document contains lecture notes on Verilog syntax and structural modeling. It discusses various Verilog concepts like commenting code, numbers and identifiers, vectors, arrays, parameters and defines, gate primitives, and hierarchy. It provides examples of modeling half adders and full adders structurally and behaviorally using primitives, modules, and always blocks. The document emphasizes choosing descriptive names and commenting code to explain the purpose or motivation behind design decisions.
1) The document describes a workshop on designing circuits using PCB Wizard software. It discusses what a printed circuit board is and different types of PCBs like single layer, double layer, and multi-layer boards.
2) It provides steps on how to design a circuit in PCB Wizard including adding components from the gallery, wiring them together, setting component values, and converting the circuit to a PCB layout.
3) An example of designing a circuit to light an LED using a thermistor is described in detail with the specific steps to build the circuit in PCB Wizard.
The document describes the design of a folded cascode operational amplifier. Key points:
- The goal is to design an op-amp with over 80dB gain, 10MHz bandwidth, 5V/us slew rate, and other specs using a folded cascode topology.
- Hand calculations are shown for determining device sizes to meet the gain, bandwidth, and slew rate specs.
- Simulation results show a gain of 17.5k, 604.7Hz bandwidth, and 3.5V/us slew rate, meeting most but not all specs.
- Analysis discusses the pros and cons of this topology, noting the difficulty of achieving high slew rate and the narrow input/
Design and implementation of 4-bit binary weighted current steering DAC IJECEIAES
A compact current-mode Digital-to-Analog converter (DAC) suitable for biomedical application is repesented in this paper. The designed DAC is binary weighted in 180nm CMOS technology with 1.8V supply voltage. In this implementation, authors have focused on calculaton of Non linearity error say INL and DNL for 4-bit DAC having various type of switches: NMOS, PMOS and transmission gate. The implemented DAC uses lower area and power compared to unary architecture due to absence of digital decoders. The desired value of Integrated non linearity (INL) and Differential non linearity (DNL) for DAC for are within a range of +0.5LSB. Result obtained in this works for INL and DNL for the case DAC using transmission gate is +0.34LSB and +0.38 LSB respectively with 22mW power dissipation.
An oscillator is an electronic circuit that produces repetitive waveforms without an external input signal. It uses positive feedback to sustain oscillations, with the frequency determined by circuit components like inductors and capacitors. Common types include sinusoidal oscillators that produce sine waves, and relaxation oscillators that produce non-sinusoidal waves like square waves. Oscillators are essential components in many electronic devices and systems to generate stable frequency signals.
System partitioning in VLSI and its considerationsSubash John
System partitioning divides a large circuit into smaller subcircuits. This allows the subcircuits to be designed independently and in parallel, speeding up the design process. Effective partitioning aims to minimize connections between subcircuits. Tool-based partitioning allows constraints to be set to generate a partitioned netlist that balances subcircuit sizes and minimizes connections between top-level blocks.
The document discusses transistor modeling for small-signal analysis. It introduces two common transistor models - the hybrid equivalent model and the re model. The re model represents the transistor with a diode and controlled current source. Important small-signal parameters for analysis are also defined, including input impedance Zi, output impedance Zo, voltage gain Av, and current gain Ai. The phase relationship between input and output signals is also addressed.
This document describes testing of a boost rectifier for a back-to-back converter used in a doubly fed induction generator wind energy system. The design of the back-to-back converter components is explained, including selection of IGBT switches, DC link capacitor, and driver circuits. A 1 kW prototype was fabricated in the laboratory. Testing was performed on the rectifier sections and showed the boosting was obtained as required. A microcontroller was used to generate PWM pulses to control the IGBTs in the boost rectifier. Experimental results demonstrated boosting of the rectified voltages for various input voltages and pulse widths.
Design of a Fully Differential Folded-Cascode Operational AmplifierSteven Ernst, PE
This document summarizes the design of a fully differential operational amplifier and a second-order Butterworth filter using the designed op-amp. The op-amp was designed using a folded-cascode topology to meet specifications across temperature variations. Simulation results showed it met most specifications. A layout was created and tested, matching the schematic performance. A Butterworth biquad filter was also designed using the op-amp, with simulation results showing corner frequencies around the specified 22kHz point across temperatures.
A printed circuit board (PCB) is a non-conductive board that mechanically supports and electrically connects electronic components using copper tracks etched onto laminated sheets. PCBs can be single-sided, double-sided, or multilayer. They were first developed in the 1930s and are used to build circuit board assemblies, with common types including single-sided, double-sided, and multilayer boards.
The document provides an overview of analog layout design. It discusses that analog circuits require careful attention to geometry during layout due to process variations. The analog design flow includes electrical design, physical design involving layout, and fabrication/testing. Key considerations for analog layout include minimizing parasitic resistances and capacitances, reducing noise, and ensuring matching between identical components using techniques like common-centroid layout. Resistors and capacitors must be carefully laid out to minimize non-ideal effects and provide accurate values.
This document describes the implementation of a bandgap reference circuit. It begins by acknowledging those who supported the project. It then provides an abstract stating that bandgap reference circuits are used to generate stable reference voltages and currents on integrated circuits. The main goal of the project was to understand bandgap reference design and limitations, and implement a bandgap reference circuit in a 90nm CMOS technology using CADENCE.
This document compares and contrasts the basic logic cells of the Xilinx LCA and Altera FLEX FPGA architectures. It describes the evolution of the Xilinx CLB from the XC3000 through XC4000 and XC5200, which all utilize LUTs of varying sizes. The Altera FLEX architecture similarly uses a four-input LUT in its basic logic element. Both architectures are based on SRAM programming technology.
The document discusses circuit design processes and stick diagrams. It begins by introducing MOS layers and objectives of understanding stick diagrams, design rules, and layout. It then covers stick diagrams in depth, explaining that they show relative component placement and layer information through color codes as an interface between symbolic circuits and layouts. Examples of stick diagram rules, notations, and common MOS circuits are provided. Finally, it discusses design rules, explaining that they define feature sizes and spacings to interface between circuits and fabrication processes while allowing for manufacturing tolerances.
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.
Of the many ways of implementing opamp in mixed mode VLSI design, two stage design is often preferred. This presentation illustrates the design process. Download for better view as it has animations
The document discusses the structure and operation of MOS transistors. It describes the basic MOS structure which consists of a metal gate separated from a semiconductor substrate by an oxide layer. Applying a voltage to the gate can induce an inversion layer in the semiconductor to form a channel between the source and drain, allowing current to flow. The threshold voltage is the minimum gate voltage required to form an inversion layer. The document discusses n-channel MOSFETs and their characteristics in different regions of operation defined by the gate-source voltage.
This chapter discusses bipolar junction transistors. It describes the basic transistor construction with PNP and NPN types. It explains transistor operation with forward biased base-emitter and reverse biased base-collector junctions. It also discusses currents in transistors including minority and majority carriers. Different transistor configurations - common base, common emitter, and common collector - are presented along with their input/output characteristics and operating regions. Key parameters like alpha, beta, and power dissipation are also covered.
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 provides an introduction to application specific integrated circuits (ASICs). It discusses that ASICs are non-standard integrated circuits designed for a specific application. The document then categorizes ASICs into three types: full-custom ASICs which have fully customized logic and mask layers; semi-custom ASICs which use predesigned logic cells and have some customized mask layers; and programmable ASICs. Within semi-custom ASICs, the document describes standard cell based and gate array based ASICs, focusing on the differences between channeled, channelless, and structured gate arrays.
The document outlines the design procedure for a two-stage operational amplifier (op amp) in CMOS technology. It begins by listing the design inputs and outputs. It then describes the steps in designing a CMOS op amp including determining the topology, compensation method, and transistor sizes. The document provides equations for analyzing key parameters of a two-stage op amp like gain, bandwidth, and common-mode range. It concludes with an example design problem demonstrating how to use the outlined procedure to design an op amp that meets given specifications.
This document contains lecture notes on Verilog syntax and structural modeling. It discusses various Verilog concepts like commenting code, numbers and identifiers, vectors, arrays, parameters and defines, gate primitives, and hierarchy. It provides examples of modeling half adders and full adders structurally and behaviorally using primitives, modules, and always blocks. The document emphasizes choosing descriptive names and commenting code to explain the purpose or motivation behind design decisions.
1) The document describes a workshop on designing circuits using PCB Wizard software. It discusses what a printed circuit board is and different types of PCBs like single layer, double layer, and multi-layer boards.
2) It provides steps on how to design a circuit in PCB Wizard including adding components from the gallery, wiring them together, setting component values, and converting the circuit to a PCB layout.
3) An example of designing a circuit to light an LED using a thermistor is described in detail with the specific steps to build the circuit in PCB Wizard.
The document describes the design of a folded cascode operational amplifier. Key points:
- The goal is to design an op-amp with over 80dB gain, 10MHz bandwidth, 5V/us slew rate, and other specs using a folded cascode topology.
- Hand calculations are shown for determining device sizes to meet the gain, bandwidth, and slew rate specs.
- Simulation results show a gain of 17.5k, 604.7Hz bandwidth, and 3.5V/us slew rate, meeting most but not all specs.
- Analysis discusses the pros and cons of this topology, noting the difficulty of achieving high slew rate and the narrow input/
Design and implementation of 4-bit binary weighted current steering DAC IJECEIAES
A compact current-mode Digital-to-Analog converter (DAC) suitable for biomedical application is repesented in this paper. The designed DAC is binary weighted in 180nm CMOS technology with 1.8V supply voltage. In this implementation, authors have focused on calculaton of Non linearity error say INL and DNL for 4-bit DAC having various type of switches: NMOS, PMOS and transmission gate. The implemented DAC uses lower area and power compared to unary architecture due to absence of digital decoders. The desired value of Integrated non linearity (INL) and Differential non linearity (DNL) for DAC for are within a range of +0.5LSB. Result obtained in this works for INL and DNL for the case DAC using transmission gate is +0.34LSB and +0.38 LSB respectively with 22mW power dissipation.
An oscillator is an electronic circuit that produces repetitive waveforms without an external input signal. It uses positive feedback to sustain oscillations, with the frequency determined by circuit components like inductors and capacitors. Common types include sinusoidal oscillators that produce sine waves, and relaxation oscillators that produce non-sinusoidal waves like square waves. Oscillators are essential components in many electronic devices and systems to generate stable frequency signals.
System partitioning in VLSI and its considerationsSubash John
System partitioning divides a large circuit into smaller subcircuits. This allows the subcircuits to be designed independently and in parallel, speeding up the design process. Effective partitioning aims to minimize connections between subcircuits. Tool-based partitioning allows constraints to be set to generate a partitioned netlist that balances subcircuit sizes and minimizes connections between top-level blocks.
The document discusses transistor modeling for small-signal analysis. It introduces two common transistor models - the hybrid equivalent model and the re model. The re model represents the transistor with a diode and controlled current source. Important small-signal parameters for analysis are also defined, including input impedance Zi, output impedance Zo, voltage gain Av, and current gain Ai. The phase relationship between input and output signals is also addressed.
This document describes testing of a boost rectifier for a back-to-back converter used in a doubly fed induction generator wind energy system. The design of the back-to-back converter components is explained, including selection of IGBT switches, DC link capacitor, and driver circuits. A 1 kW prototype was fabricated in the laboratory. Testing was performed on the rectifier sections and showed the boosting was obtained as required. A microcontroller was used to generate PWM pulses to control the IGBTs in the boost rectifier. Experimental results demonstrated boosting of the rectified voltages for various input voltages and pulse widths.
Low Power Full Adder using 9T Structureidescitation
In this paper, we propose a new 9T 1-bit full adder.
The main objective is full output voltage swing, low power
consumption and temperature sustainability. The proposed
design is more reliable in terms of power consumption, Power
Delay Product (PDP) and temperature sustainability as
compared to the existing full adder designs. The design has
been implemented 45nm technology on Tanner EDA Tool
version 13.0. The simulation results demonstrate the power
consumption, delay and power delay product at different input
voltages ranging 0.4V to 1.4V.
Use of multilevel inverters have been widely accepted as an effective solution for high power and high voltage applications. The performance of a multilevel inverter is superior to that of traditional inverters due to their advantages such as, reduced THD, less switching stress, lower EMI. Different types of topologies and modulation techniques for multilevel inverters have been discussed in the recent literature. In this paper three phase multilevel inverter based on Diode Clamped Multilevel DC Link (DC-MLDCL) and full bridge inverter has been proposed to reduce switch count and THD using multi reference based modulation techniques. The proposed multi reference modulation techniques are based on sinusoidal and third harmonic reference wave compared with U-type carrier wave. The performance parameters for the proposed DC-MLDCL inverter are analyzed in terms of THD, fundamental output line voltage and output line current for R and RL loads. The results are verified through MATLAB/simulation tool to verify the results of the proposed three phase seven level DC-MLDCL inverter .
1) The document proposes a new inverter design for Flexible AC Transmission System (FACTS) applications to improve efficiency.
2) The proposed inverter uses fewer switches than conventional cascaded H-bridge multilevel inverters, reducing switching losses. It produces 7 voltage levels using only 8 switches and 4 DC sources, whereas conventional designs require 12 switches and 3 DC sources.
3) Simulation results show that the proposed inverter produces voltage waveforms with lower harmonic content when used in a Static Synchronous Series Compensator (SSSC) FACTS controller, demonstrating its potential to improve FACTS system performance with reduced complexity.
This document presents the design of a high performance folded cascade OTA and sample and hold circuit. The OTA is designed to achieve 10-bit resolution while operating at a 28 MHz sampling frequency. Simulation results show the OTA achieves a high open loop gain of 72 dB and bandwidth of 112 MHz, with a phase margin of 73 degrees. A low resistance transmission gate switch is designed to reduce charge injection and clock feedthrough effects during sampling. The circuit is implemented in a 130 nm CMOS technology.
Three Phase Seven-level Triple Voltage Booster Switched-Capacitors based Mult...IRJET Journal
This document describes a proposed three-phase seven-level triple voltage booster switched-capacitor multilevel inverter with minimal components. The proposed inverter configuration uses a single DC source and only six switching components per phase leg to produce a seven-level output voltage waveform from line to line. It features built-in capacitor voltage balancing and a voltage boosting capability of three times the input voltage. Simulation results demonstrate the feasibility and effectiveness of the proposed inverter topology compared to existing multilevel inverter configurations.
Design a Low Power High Speed Full Adder Using AVL Technique Based on CMOS Na...IOSR Journals
Abstract: Power and delay optimization is a very crucial issue in low voltage applications. In this paper, we present a design of Full Adder circuit using AVL techniques for low power operation. The approach for the design is based on XOR/XNOR & Transmission gate for single bit as hybrid design .By using this approach Full Adder is being designed using 12 transistors. We can reduce the value of total power dissipation by applying the AVLG (adaptive voltage level at ground) technology in which the ground potential is raised and AVLS (adaptive voltage level at supply) in which supply potential is increased. The main aim of the design is to investigate the power, Propagation Delay and Power delay Product for low voltage Full Adder for the proposed design style. The simulation results show that there is a significant reduction in power consumption for this proposed cell with the AVL technique. The circuit is designed using 65 nanometer CMOS technology and simulated using MicroWind and DSCH Ver. 3.1 Keywords: Full Adder, AVL Techniques, Low Power, VLSI, High Performance
Application of SVM Technique for Three Phase Three Leg Ac/Ac Converter TopologyIOSR Journals
This paper presents a simulation of a three-phase three-leg AC/AC converter topology using nine IGBTs and space vector pulse width modulation (SVM) technique. The proposed topology reduces the number of switches compared to conventional back-to-back and matrix converters. Simulation results show the converter provides sinusoidal input and output voltages with unity power factor under constant frequency and variable frequency operation. Experimental results from a 5kVA prototype verify the validity of the proposed scheme.
Physical designing of low power operational amplifierDevendra Kushwaha
The document provides details about a master's thesis project to design a novel low power operational amplifier. It begins with an introduction to operational amplifiers, describing their basic structure and ideal characteristics. The literature review discusses previous work on designing low power and low noise operational amplifiers using techniques like current driven bulk, Miller compensation, and class AB amplifiers. Key inferences from the literature are that most work has been done on 120nm CMOS technology, noise can be reduced by adjusting transconductance, and cascoded structures provide better gain than cascaded structures. The document outlines the scope of work, methodology, expected outcomes, and software requirements for the thesis project.
Analysis of 7-Level Cascaded & MLDCLI with Sinusoidal PWM & Modified Referenc...IJMTST Journal
This document compares the performance of a 7-level cascaded multilevel inverter and a 7-level multilevel DC link inverter (MLDCLI) using sinusoidal PWM and modified reference PWM control techniques. Simulation results show that the 7-level MLDCLI with modified reference PWM produces the highest fundamental output voltage with the lowest total harmonic distortion. The MLDCLI topology requires fewer switches and components than other multilevel inverter topologies as the number of voltage levels increases, making it advantageous for higher level designs.
Modified T-type topology of three-phase multi-level inverter for photovoltaic...IJECEIAES
In this article, a three-phase multilevel neutral-point-clamped inverter with a modified t-type structure of switches is proposed. A pulse width modulation (PWM) scheme of the proposed inverter is also developed. The proposed topology of the multilevel inverter has the advantage of being simple, on the one hand since it does contain only semiconductors in reduced number (corresponding to the number of required voltage levels), and no other components such as switching or flying capacitors, and on the other hand, the control scheme is much simpler and more suitable for variable frequency and voltage control. The performances of this inverter are analyzed through simulations carried out in the MATLAB/Simulink environment on a threephase inverter with 9 levels. In all simulations, the proposed topology is connected with R-load or RL-load without any output filter.
A Simulation Based Analysis of Lowering Dynamic Power in a CMOS Inverteridescitation
With the increase in demand of high fidelity
portable devices, there is more and more emphasis laying
down on the development of low power and high performance
systems. In the next generation processors, the low power
design has to be incorporated into fundamental computation
units, such as adder. CMOS circuit design plays a crucial role
in designing of these computation units (like adder and
multiplier) so if there is any optimal way to reduce the power
dissipation in CMOS circuits then it will directly lower down
the power dissipation of other circuits and logic gates as well.
In this paper we have studied and analyzed different
techniques to reduce the dynamic power of CMOS circuit
with the help of performing simulation on some significant
factors (i.e device characteristics) of respective circuitry
designs by using Cadence-Virtuoso tool.
The document provides an overview of physical design in VLSI. It discusses the VLSI design flow including specification, schematic design, layout, floorplanning, routing, and fabrication. It then describes layout considerations such as layers, design rules, DRC checks, and LVS checks. Examples of CMOS inverter, NAND and NOR gate layouts are shown. Optimization techniques for transistor sizing and drain connections are also covered. Different logic styles like pseudo-NMOS, dynamic CMOS, and domino logic are explained.
This document provides an overview of the physical design process for integrated circuits. It discusses the steps from schematic design to layout, including floorplanning, placement, routing, and design rule checking. Sample schematics and layouts are shown for basic gates like inverters, NAND gates, and transmission gates. Guidelines are provided for layout optimization to improve performance and density. The layout process involves translating the schematic into distinct layers and ensuring design rules are followed with respect to dimensions, spacing, and connectivity between layers.
Write your own generic SPICE Power Supplies controller modelsTsuyoshi Horigome
This document discusses writing generic SPICE models for power supply controllers. It begins by explaining that exact SPICE models may not exist or be compatible with the user's simulator. The solution is to write a generic model and adapt it to the specific controller. It then provides examples of using behavioral (B) elements to model nonlinear functions like comparators and logic gates in different simulators like ISspice, PSpice, and AWB. Guidelines are given for writing models step-by-step, including using subcircuits and descriptive names. Finally, it discusses modeling a constant frequency current mode PWM controller as an example application.
- A Wilkinson power divider is a three-port microwave device that divides input power equally between two output ports while isolating the ports from one another.
- The document describes designing Wilkinson power dividers at 3 GHz using both lumped element and distributed element simulations in HFSS.
- Key steps include calculating component values, laying out transmission lines, and simulating to validate equal power division between ports and isolation between outputs.
Analysis and design_of_a_low-voltage_low-power[1]Srinivas Naidu
The document presents an analysis of the delay characteristics of dynamic comparators. It analyzes the delay of conventional dynamic and double-tail comparators, deriving analytical expressions showing the impact of various design parameters on delay. A new dynamic comparator is then proposed based on modifying the circuit of a conventional double-tail comparator to strengthen positive feedback, reducing delay time. Simulation results on the proposed comparator show significantly reduced power consumption and delay compared to conventional designs, enabling higher clock frequencies at lower supply voltages.
Design of High-Speed Dynamic Double-Tail ComparatorIJERDJOURNAL
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A SYSTEMATIC RISK ASSESSMENT APPROACH FOR SECURING THE SMART IRRIGATION SYSTEMS
CMOS Operational Amplifier Design
1. ELEC 4609 A1O - Integrated Circuit Design & Fabrication
Op-Amp Design Project
45NM CMOS OP-AMP DESIGN
April 11, 2019
Rashad Alsaffar - 101006781
Carleton University
Department of Electronics
2. Op-Amp Report Rashad Alsaffar - 101006781
1 Introduction
The purpose of this project was to explore schematic and layout design approaches of an opera-
tional amplifier using 45nm SOI CMOS process within Cadence Virtuoso, operating from a 1.2V
supply. Analog integrated circuit introduces new techniques for schematic-level simulation of indi-
vidual MOSFET performance and contribution to the final product. Layout can be explored through
several mediums as we will explore.
The following schematic was built within Cadence Virtuoso, detailing the multiple stages of the
operational amplifier, including bias, differential-input, gain and output buffering stages:
Figure 1: Two-Stage Op-Amp Schematic-View Design [1]
Each transistor within the schematic above played a dedicated role within its stage. The transistor
sizing dimensions were provided and implemented into Cadence within the table below:
Figure 2: Two-Stage Op-Amp Original FET Dimensions [1]
Unfortunately simulation errors were experienced using said values provided in the figure above, and
instead alternative values were utilized for FET dimensions (see Figure 18 in the attached Appendix),
utilizing variables WR = 7nm and L = 200nm.
3. Op-Amp Report Rashad Alsaffar - 101006781
2 Schematic Design
The gdpk045 library was utilized, providing nmos1v and pmos1v components translating to NMOS
and PMOS devices, respectively. The two-stage op-amp display from Figure 1 was implemented
within Cadence as a fully operational schematic:
Figure 3: Implemented Two-Stage Op-Amp Schematic
All transistor sizing is visible within the schematic above, as well as the names of each device in
correlation with the pre-conceived schematic within Figure 1.
Initially body effect was negated by connecting the bulk of each device to their relative source. Un-
fortunately, this could not be implemented within layout or within the IC fabrication/manufacturing
stages due to the limitations of poly and metal materials. Instead, the bulk connections of each
device were connected properly to one of the power lines, VDD or VSS; NMOS device bulk connec-
tions were established through VSS and PMOS device bulk connections were established through VDD.
Confirmation of the finalized schematic by a TA allowed for the procedure of symbol generation
and simulations via testbenches using ADE L Spectre tools.
Figure 4: Implemented Two-Stage Op-Amp Test Bench
4. Op-Amp Report Rashad Alsaffar - 101006781
The middle figure was the generated symbol of the op-amp with designated power lines VDD and
VSS, differential inputs Vin+ and Vin−, as well as a circuit output VOUT .
Supplied test benches within ADE L provided several testing conditions for four simulations: Voffset,
Open-Loop Gain, Risetime (10%-90%) and Falltime (10%-90%). Simulation conditions provided
functioning simulations for risetime and falltime test benches, while the remaining two would be
tested using ADE XL tools.
Figure 5: Op-Amp Risetime (10%-90%) Spectre Simulation
Figure 6: Op-Amp Falltime (10%-90%) Spectre Simulation
5. Op-Amp Report Rashad Alsaffar - 101006781
The simulation plots above characterize an approximate device risetime of 0.4µs and approximate
device falltime of 60ns. The provided plots above however characterize transient test benches under
nominal conditions, i.e. NN, 1.2V, 25◦
C
Advanced ADE XL simualtion tools were required to test the device across fast and slow performance
speeds as characterized by the table below; variations include supply voltage and temperature:
Figure 7: Two-Stage Op-Amp PVT Variations [1]
Multiple temperature conditions were considered when simulating PVT variations within ADE XL.
The original test benches within ADE L were imported within the enhanced design environment and
new test simulations were performed in detail below:
Figure 8: Two-Stage Op-Amp PVT Data Simulations
Important device parameters of the op-amp can be found in the figure above, including Voffset, open-
loop gain, unity-gain bandwidth (UGBW), phase margin and power dissipation. The table below
identifies the particular values characterized by the device response:
Figure 9: Two-Stage Op-Amp PVT Data Simulations (Condensed)
Circuit performance is in fact very dependant on temperature and environmental effects. Progression
of the device will now scale into layout design.
6. Op-Amp Report Rashad Alsaffar - 101006781
3 Layout Design
We will discuss the multitude of techniques involved with Analog CMOS IC design, including device
orientation, matching, parasitic compensation, fingers, etc.
3.1 Transistor Layout Structure
It is important for the MOSFET devices to have multiple contacts across the source and drain, so
as to avoid micro-fractures and parasitic resistance within the device.
Analog transistor devices with a large W
L
ratio may experience unwanted parasitic capacitance be-
tween bulk connections. To negate this effect, transistors can be split into multiple ”fingers” in order
to compensate for the total width of the device whilst reducing parasitic capacitance.
The figure below details the nmos1v layout design obtained from the gdpk045 library. The transis-
tor above provides a width of 3µm. This is quite large, however the transistor can be ”shrunk” by
providing multiple fingers, three in particular, with each finger width providing W
3
= 1µm.
Figure 10: Wide Analog Transistor Fingers Demonstration
The particular example above demonstrates 1
3
bulk-parasitic capacitance reduction between the
source and drain of the transistor.
3.2 Matching
Matching is one of the most important considerations in Analog CMOS IC design. Layout designers
aim to ”match” transistors. This is apparent particularly when trying to match gate-source voltage
VGS across a differential pair, or matching current across a current mirror.
Matching can present itself in the form of device orientation, interconnections, matching metal con-
nections, and reduction of unwanted parasitic capacitance/resistance.
3.2.1 Dummy Elements
Passive components can be matched by providing ”dummy elements”; added layers that have no
layout functionality or electrical connections. The purpose of including them is to provide symme-
try within an environment of components, improving the reliability and yield of the chip during
fabrication. For example, dummies can be utilized as shorted transistors.
7. Op-Amp Report Rashad Alsaffar - 101006781
3.3 Layout Methods
Two particular analog layout design methods will be discussed in detail pertaining to the layout
design of our op-amp.
3.3.1 Interdigitated Devices
A common example we will examine is matching two transistors with a common node:
Figure 11: Common-node Transistor Setup
The process gradint is almost evenly distributed between split-up devices A and B; we will say each
possess four fingers. The combined eight elements can be interdigitated into the following forms:
AABBAABB or ABBAABBA
3.3.2 Common-Centroid Devices
Using the same transistor configuration as described in Figure 11 (now using two finger), an al-
ternative design method known as common-centroid layout can be utilized. Its advantages are the
multitude of patterns/device organization and compensated process gradients.
It is important for devices organized in this manner to follow certain design rules including sym-
metry to both x and y axes, dispersion of elements within the ”array” whilst orienting the array
elements properly and making it as compact as possible.
A & B represent the active poly layer correlating to the respected transistor device. The follow-
ing figures below translate the interdigitated and common-centroid representations in the form of
a layout (note metal connections are not drawn to scale nor do they represent proper design rules,
strictly for presentation):
Figure 12: Interdigitated Layout Example Figure 13: Common-Centroid Layout Example
8. Op-Amp Report Rashad Alsaffar - 101006781
3.4 Stacked Layout
One of the most important stages of analog layout design is the setup of a stacked layout diagram.
Multi-finger common-width transistor devices can be ”stacked”.
The original schematic displayed in Figure 1 can be utilized for the stacked layout procedure. Com-
mon devices can be grouped together within the same stack; equivalent sizes must be considered for
critical transistors.
3.5 Stick Diagram
A stick diagram is composed of single poly line fingers with indicated drain and source connections.
This ”stick-like” figure can expand within multi-transitor schematics which we will use to break down
our op-amp.
Assuming the width of MOSFETs A and B within the schematic characeterized in Figure 11, the
stick diagram would correspond below:
Figure 14: Mult-Transistor Stick Diagram
3.6 Top Level Floorplan
A top level floorplan can be constructed from the given transistor sizes. As instructed we were allowed
to change the number of fingers per transistor while making sure each device’s W
L
ratio remained
the same. Due to unknown W
L
ratios from the used transistor values involved with the generated
simulation, i.e. Appendix tabulated values, and instead the values detailed in Figure 2 were used as
a starting point for a floorplan generation.
Figure 15: Schematic Grouping of Transistors for Top Level Floorplan
9. Op-Amp Report Rashad Alsaffar - 101006781
The image above details the grouping of transistors based on transistor type and dependency on
mirroring devices. This may not have been the most appropriate approach, however I will detail the
entire procedure and briefly discuss an alternative grouping method.
Several calculations were put into place to manipulate the existing values of the transistor dimen-
sions. As previously mentioned, transistor length/width as well as finger size could change as long
as the W
L
ratio remained the same. To ensure this, careful consideration was taken to provide an
equivalent amount of fingers across each side of the floorplan.
The figure below details the newly defined transistor dimension values:
Figure 16: Updated Values of Transistor Dimensions for Top Level Floorplan
The initial design decision had been to establish a common-centroid orientation across the entire
layout; symmetry conditions were established to mimic the particular layout finger placements.
It should be noted that the transistors connected to the compensation capacitor and bias resis-
tor, as well as devices involved with the structuring of the output buffer stage were all attached
separately. Consideration was taken with regards to the placement of each device within the floor-
plan. The output buffer devices were stationed at the top and bottom rows of the floor plan while
the remaining devices were placed on opposite sides attached to their relevant stage (device Q15
within the bias stage and device Q16 within the common-source gain stage).
Initially the first step was to assign 12 fingers to each of the devices within the differential pair (Q1
and Q2), as well as making it the center-point of the entire layout, i.e. establish common-centroid
symmetry matching with respect to the differential pair. Each device was assigned 12 fingers as per
its original standard. From this point on the top row of PMOS devices and bottom row of NMOS
devices (see grouping in Figure 15) were grouped and were set to total the same number of fingers
as the differential pair. Careful consideration was taken with regards to devices established within
a current mirror being identical, devices within a following stage having a larger number of fingers
than devices in prior stages, etc.
Devices involved within current mirrors shared equivalent dimensions and finger quantity. It was
important that critical devices involved within current mirrors were identical with each other. Inter-
digitated layout techniques were primarily used for the isolated differential pair.
10. Op-Amp Report Rashad Alsaffar - 101006781
In between the four symmetric 4-finger transistors were pairs that were cut down in finger size to
equal a total of 12 on the top and bottom row. The output buffer pair was a noticeable opportunity
for symmetry above and below the floorplan.
The main design decisions involved with the calculations surrounded the initial floorplan group-
ing as displayed in Figure 15. The detailed image below displays the full floorplan below:
Figure 17: Final Top Level Floorplan
3.7 Alternative Floorplan Design
As previously mentioned, there were slight issues involved with the original floorplan process. For
example, it was a challenge to distribute an equal number of fingers towards the devices within
each group of transistors, particularly with an uneven number of transistors between the NMOS and
PMOS row.
An alternative method would be further examination of the W
L
ratios of each device, as well as
a common factor between groups of transistors that can be used to determine the appropriate dis-
tribution of fingers among the grouped devices.
3.8 Layout Results
Initially the layout had been attempted using the updated transistor dimension values as seen in the
Appendix. Unfortunately, this caused many issues with regards to layout generation and editing.
Sizing and proper orientation was very small, and therefore this attempt was avoided.
Future plans are to enhance the initial floorplan and produce a functioning analog CMOS IC layout.
Layout design with original values would have to be considered due to the shortcomings I faced
during layout generation.
11. Op-Amp Report Rashad Alsaffar - 101006781
4 References
[1]: R. Amaya, ”Op-Amp Project v4”, 4609 IC Design and Fabrication, Accessed link:
https://culearn.carleton.ca/moodle/pluginfile.php/2959298/mod resource/content/2/ELEC4609 OpAm
5 Appendix
5.1 Alternate Transistor Sizing
Figure 18: Two-Stage Op-Amp Schematic Transistor Alternative Dimensions