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A simple CMOS Operational Amplifier

Integrated circuit design, or IC design, is a subset of electrical engineering, encompassing the particular logic and circuit design techniques required to design integrated circuits, or ICs. ICs consist of miniaturized electronic components built into an electrical network on a monolithic semiconductor substrate by photolithography. Image File history File links Size of this preview: 800 × 420 pixelsFull resolution (1204 × 632 pixel, file size: 50 KB, MIME type: image/gif) CMOS Op-amp (dual-stage) Created by me for a VLSI course. ... Image File history File links Size of this preview: 800 × 420 pixelsFull resolution (1204 × 632 pixel, file size: 50 KB, MIME type: image/gif) CMOS Op-amp (dual-stage) Created by me for a VLSI course. ... Electrical Engineers design power systems… … and complex electronic circuits. ... Boolean logic is a complete system for logical operations. ... The process of circuit design can cover systems ranging from national power grids all the way down to the individual transistors within an integrated circuit. ... An integrated circuit (IC) is a thin chip consisting of at least two interconnected semiconductor devices, mainly transistors, as well as passive components like resistors. ... An electronic component is a basic electronic building block packaged in a discrete form with two or more connecting leads or metallic pads. ... This article or section does not adequately cite its references or sources. ... Something that is monolithic is something created in one piece, resembling a monolith such as an obelisk. ... A semiconductor is a solid whose electrical conductivity can be controlled over a wide range, either permanently or dynamically. ... Photolithography is a process used in semiconductor device fabrication to transfer a pattern from a photomask (also called reticle) to the surface of a substrate. ...

IC design can be divided into the broad categories of digital and analog IC design. Digital IC design is used to produce components such as microprocessors, FPGAs, memories (RAM, ROM, and flash) and digital ASICs. Digital design focuses on logical correctness, maximizing circuit density, and placing circuits so that clock and timing signals are routed efficiently. Analog IC design also has specializations in power IC design and RF IC design. Analog IC design is used in the design of op-amps, linear regulators, phase locked loops, oscillators and active filters. Analog design is more concerned with the physics of the semiconductor devices such as gain, matching, power dissipation, and resistance. Fidelity of analog signal amplification and filtering is usually critical and as a result, analog ICs use larger area active devices than digital designs and are usually less dense in circuitry. A digital system is one that uses discrete values (often electrical voltages), especially those representable as binary numbers, or non-numeric symbols such as letters or icons, for input, processing, transmission, storage, or display, rather than a continuous spectrum of values (ie, as in an analog system). ... Wikipedia does not yet have an article with this exact name. ... Microprocessors, including an Intel 80486DX2 and an Intel 80386 A microprocessor (abbreviated as µP or uP) is an electronic computer central processing unit (CPU) made from miniaturized transistors and other circuit elements on a single semiconductor integrated circuit (IC) (aka microchip or just chip). ... A field-programmable gate array or FPGA is a gate array that can be reprogrammed after it is manufactured, rather than having its programming fixed during the manufacturing — a programmable logic device. ... Look up RAM, Ram, ram in Wiktionary, the free dictionary. ... Read-only memory (usually known by its acronym, ROM) is a class of storage media used in computers and other electronic devices. ... A USB flash drive. ... The acronym ASIC, depending on context, may stand for: Application-specific integrated circuit ASIC programming language Australian Securities and Investments Commission This is a disambiguation page — a navigational aid which lists pages that might otherwise share the same title. ... It has been suggested that this article or section be merged with Radio waves. ... An operational amplifier or op-amp is an electronic circuit module (normally built as an integrated circuit, but occasionally with discrete transistors or vacuum tubes) which has a non-inverting input (+), an inverting input (-) and one output. ... In electronics, a linear regulator is a voltage regulator based on a transistor operating in its linear region. That transistor acts like a variable resistor. ... Many electronic systems use internal clocks which are required to be phase-aligned to and/or frequency multiples of some external reference clock. ... Oscillation is the periodic variation, typically in time, of some measure as seen, for example, in a swinging pendulum. ... An example of high-pass active filter. ...

Modern ICs are enormously complicated. A large chip, as of 2006, may well have more transistors than there are people on Earth. The rules for what can and cannot be manufactured are also extremely complex. An IC process as of 2006 may well have more than 600 rules. Furthermore, since the manufacturing process itself is not completely predictable, designers must account for its statistical nature. The complexity of modern IC design, as well as market pressure to produce designs rapidly, has led to the extensive use of automated design tools in the IC design process. Design Rule Checking or Check(s) (DRC) is the area of Electronic Design Automation software that determines whether a particular chip design satisfies a series of recommended parameters called Design Rules. ... A graph of a Normal bell curve showing statistics used in educational assessment and comparing various grading methods. ... PCB Layout Program Electronic design automation (EDA) is the category of tools for designing and producing electronic systems ranging from printed circuit boards (PCBs) to integrated circuits. ...

Fundamentals

Integrated circuit design involves the creation of electronic components, such as transistors, resistors, capacitors and the metallic interconnect of these components onto a piece of semiconductor, typically silicon. A method to isolate the individual components formed in the substrate is necessary since the substrate silicon is conductive and often forms an active region of the individual components. The two common methods are p-n junction isolation and dielectric isolation. Attention must be given to power dissipation of transistors and interconnect resistances and current density of the interconnect, contacts and vias since ICs contain very tiny devices compared to discrete components, where such concerns are less of an issue. Electromigration in metallic interconnect and ESD damage to the tiny components are also of concern. Finally, the physical layout of certain circuit subblocks is typically critical, in order to achieve the desired speed of operation, to segregate noisy portions of an IC from quiet portions, to balance the effects of heat generation across the IC, or to facilitate the placement of connections to circuitry outside the IC. Photo of transistor types (tape measure marked in centimeters) Transistor in the SMD form factor The transistor is a solid state semiconductor device used for amplification and switching. ... An ideal resistor is a component with an electrical resistance that remains constant regardless of the applied voltage or current flowing through the device. ... Various types of capacitors A capacitor is a device that stores energy in the electric field created between a pair of conductors on which equal but opposite electric charges have been placed. ... The term connection (also rendered connexion - this alternative spelling is now generally considered old-fashioned, but it was the house style of The Times of London until at least the late 1970s) has various uses, including: An act of connecting two or more physical entities in a physical sense or... It has been suggested that Silicons ranking be merged into this article or section. ... It has been suggested that Wafer prober be merged into this article or section. ... p-n junction isolation is a method used to electrically isolate electronic components, such as transistors, on an integrated circuit (IC) by surrounding the components with reverse biased p-n junctions. ... The term connection (also rendered connexion - this alternative spelling is now generally considered old-fashioned, but it was the house style of The Times of London until at least the late 1970s) has various uses, including: An act of connecting two or more physical entities in a physical sense or... Contacts can refer to: Contact Short form for collection of contact information Contact lens This is a disambiguation page — a navigational aid which lists other pages that might otherwise share the same title. ... In PCB design, via refers to a pad with a plated hole that connects copper tracks from one layer of the board to other layer(s). ... Electromigration is the transport of material caused by the gradual movement of the ions in a conductor due to the momentum transfer between conducting electrons and diffusing metal atoms. ... To meet Wikipedias quality standards, this article or section may require cleanup. ...

Design steps

A typical IC design cycle involves several steps:

1. Feasibility study and die size estimate
2. Functional verification
3. Circuit design
4. Circuit simulation
5. Floorplanning
6. Design review
7. Layout
8. Layout verification
9. Layout review
10. Design For Test and Automatic test pattern generation
11. Design for manufacturability (IC)
12. Mask data preparation
13. Wafer fabrication
14. Die test
15. Packaging
16. Device characterization
17. Tweak (if necessary)
18. Datasheet generation

Functional verification, in electronic design automation, is the task of verifying that the logic design conforms to specification. ... “Spiciness” redirects here. ... Integrated circuit layout, also known IC layout or IC mask layout is the representation of an integrated circuit in terms of planar geometric shapes that correspond to shapes actually drawn on photomasks used in semiconductor device fabrication. ... Design-for-Test Design for Test (also known as Design for Testability, or DFT for short) is a methodology commonly employed during the design of integrated circuits. ... // Introduction ATPG, or Automatic test pattern generation is an electronic design automation tool that attempts to find an input (or test) sequence that, when applied to a digital circuit, enables testers to distinguish between the correct circuit behavior and the faulty circuit behavior caused by a particular fault. ... Achieving high-yielding designs in the state of the art, ULSI technology has become an extremely challenging task due to the miniaturization as well as the complexity of leading-edge products. ... Mask data preparation is the step that translates an intended set of polygons on an integrated circuit layout into a form that can be physically written by the photomask writer. ... NASAs Glenn Research Center cleanroom. ... NASAs Glenn Research Center cleanroom. ... Integrated circuit packaging is the final stage of semiconductor device fabrication per se, followed by IC testing. ...

Digital design

Roughly speaking, digital IC design can be divided into three parts

• ESL design: This step creates the user functional specification. The user may use a variety of languages and tools to create this description. Examples include a C/C++ model, SystemC, SystemVerilog Transaction Level Models, Simulink and Matlab.
• RTL design: This step converts the user specification (what the user wants the chip to do) into a register transfer level (RTL) description. The RTL specifies, in painstaking detail, exactly what every bit of the chip should do on every clock cycle.
• Physical design: This step takes the RTL, and a library of available logic gates, and creates a chip design. This involves figuring out which gates to use, defining places for them, and wiring them together.

Note that the second step, RTL design, is responsible for the chip doing the right thing. The third step, physical design, does not affect the functionality at all (if done correctly) but determines how fast the chip operates and how much it costs. Due to technical limitations, C# redirects here. ... C++ (pronounced see plus plus, IPA: ) is a general-purpose, high-level programming language with low-level facilities. ... SystemC is often thought of as a hardware description language like VHDL and Verilog, but is more aptly described as a system description language, since it exhibits its real power during transaction-level modeling and behavioral modeling. ... SystemVerilog is a combined Hardware Description Language and Hardware Verification Language based on extensions to Verilog. ... Transaction-level modeling (TLM) is a high-level approach to modeling digital systems where details of communication among modules are separated from the details of the implementation of functional units or of the communication architecture. ... Simulink, running a simulation of a thermostat-controlled heating system Simulink® is a block library tool for modeling, simulating and analyzing dynamic systems. ... MATLAB is a numerical computing environment and programming language. ... Register transfer level description (RTL), also called register transfer logic is a description of a digital electronic circuit in terms of data flow between registers, which store information between clock cycles in a digital circuit. ...

RTL design

This is the hardest part, and the domain of functional verification. The spec may have some terse description, such as encodes in the MP3 format or implements IEEE floating-point arithmetic. Each of these innocent looking statements expands to hundreds of pages of text, and thousands of lines of computer code. It is extremely difficult to verify that the RTL will do the right thing in all the possible cases that the user may throw at it. Many techniques are used, none of them perfect but all of them useful – extensive logic simulation, formal methods, hardware emulation, lint-like code checking, and so on. Functional verification, in electronic design automation, is the task of verifying that the logic design conforms to specification. ... MPEG-1 Audio Layer 3, more commonly referred to as MP3, is a popular digital audio encoding format. ... The IEEE Standard for Binary Floating-Point Arithmetic (IEEE 754) is the most widely-used standard for floating-point computation, and is followed by many CPU and FPU implementations. ... Logic simulation is the use of a computer program to simulate the operation of a digital circuit. ... In computer science and software engineering, formal methods are mathematically-based techniques for the specification, development and verification of software and hardware systems. ... Hardware emulation is the process of imitating the behavior of one piece of hardware (typically a system under design) with another piece of hardware, typically a special purpose emulation system. ... Lint is a computer programming tool that performs the lexical and syntactic portions of the compilation with substantial additional checks, noting when variables had been used before being set, when they were used as a datatype other than that of their definition, and numerous other programming errors. ...

A tiny error here can make the whole chip useless, or worse. The famous Pentium FDIV bug caused the results of a division to be wrong by at most 61 parts per million, in cases that occurred very infrequently. No one even noticed it until the chip had been in production for months. Yet Intel was forced to offer to replace, for free, every chip sold until they could fix the bug, at a cost of $475 million (US). On October 30, 1994, Professor Thomas Nicely who was then at Lynchburg College reported a bug in the Pentium floating point unit. ... Intel Corporation (NASDAQ: INTC, SEHK: 4335), founded in 1968 as Integrated Electronics Corporation, is an American multinational corporation that is best known for designing and manufacturing microprocessors and specialized integrated circuits. ...

Physical design

Here are the main steps of physical design. In practice there is not a straightforward progression - considerable iteration is required to ensure all objectives are met simultaneously. This is a difficult problem in its own right, called design closure. Design closure is the process by which a VLSI design is modified from its initial description to meet a growing list of design constraints and objectives. ...

• Floorplanning: The RTL of the chip is assigned to gross regions of the chip, input/output (I/O) pins are assigned and large objects (arrays, cores, etc.) are placed.
• Logic synthesis: The RTL is mapped into a gate-level netlist in the target technology of the chip.
• Placement: The gates in the netlist are assigned to nonoverlapping locations on the die area.
• Logic/placement refinement: Iterative logical and placement transformations to close performance and power constraints.
• Clock insertion: Balanced buffered clock trees are introduced into the design.
• Routing: The wires that connect the gates in the netlist are added.
• Postwiring optimization: Remaining performance(Timing Closure), noise(Signal Integrity), and yield(Design For Manufacturability) violations are removed.
• Design for manufacturability: The design is modified, where possible, to make it as easy and efficient as possible to produce. This is achieved by adding extra vias or adding dummy metal/diffusion/poly layers wherever possible while complying to the design rules set by the foundry.
• Final checking: Since errors are expensive, time consuming and hard to spot, extensive error checking is the rule, making sure the mapping to logic was done correctly, and checking that the manufacturing rules were followed faithfully.
• Tapeout and mask generation: the design data is turned into photomasks in mask data preparation.

Definition: The act of designing a birds eye view of a structure (eg: house). ... Logic synthesis is a process by which an abstract form of desired circuit behavior (typically register transfer level (RTL) or behavioral) is turned into a design implementation in terms of logic gates. ... Placement is an essential step in electronic design automation - the portion of the physical design flow that assigns exact locations for various circuit components within the chip’s core area. ... In a synchronous digital system, the clock signal is used to define a time reference for the movement of data within that system. ... Routing is a crucial step in the design of integrated circuits. ... Timing Closure is the process by which an FPGA or a VLSI design is modified to meet its timing requirements. ... Achieving high-yielding designs in the state of the art, ULSI technology has become an extremely challenging task due to the miniaturization as well as the complexity of leading-edge products. ... Formal equivalence checking process is a part of Electronic Design Automation, commonly used during the development of digital integrated circuits, to formally prove that two representations of a circuit design exhibit exactly the same behavior. ... Design Rule Checking or Check(s) (DRC) is the area of Electronic Design Automation software that determines whether a particular chip design satisfies a series of recommended parameters called Design Rules. ... In electronics, tape-out is the name of the final stage of the design of an integrated circuit such as a microprocessor, the point at which the description of a circuit is sent for manufacture. ... As used in photolithography, a photomask is typically a transparent fused quartz blank covered with a pattern defined with chrome metal as the absorbing film. ... Mask data preparation is the step that translates an intended set of polygons on an integrated circuit layout into a form that can be physically written by the photomask writer. ...

Analog design

Before the advent of the microprocessor and software based design tools, analog ICs were designed using hand calculations. These ICs were basic circuits, op-amps are one example, usually involving no more than ten transistors and few connections. An iterative trial-and-error process and "overengineering" of device size was often necessary to achieve a manufacturable IC. Reuse of proven designs allowed progressively more complicated ICs to be built upon prior knowledge. When inexpensive computer processing became available in the 1970s, computer programs were written to simulate circuit designs with greater accuracy than practical by hand calculation. The first circuit simulator for analog ICs was called SPICE (Simulation Program with Integrated Circuits Emphasis). Computerized circuit simulation tools enable greater IC design complexity than hand calculations can achieve, making the design of analog ASICs practical. The computerized circuit simulators also enable mistakes to be found early in the design cycle before a physical device is fabricated. Additionally, a computerized circuit simulator can implement more sophisticated device models and circuit analysis too tedious for hand calculations, permitting Monte Carlo analysis and process sensitivity analysis to be practical. The effects of parameters such as temperature variation, doping concentration variation and statistical process variations can be simulated easily to determine if an IC design is manufacturable. Overall, computerized circuit simulation enables a higher degree of confidence that the circuit will work as expected upon manufacture. An operational amplifier or op-amp is an electronic circuit module (normally built as an integrated circuit, but occasionally with discrete transistors or vacuum tubes) which has a non-inverting input (+), an inverting input (-) and one output. ... “Spiciness” redirects here. ... This article does not cite any references or sources. ... NASAs Glenn Research Center cleanroom. ... Monte Carlo methods are algorithms for solving various kinds of computational problems by using random numbers (or more often pseudo-random numbers), as opposed to deterministic algorithms. ... Achieving high-yielding designs in the state of the art, ULSI technology has become an extremely challenging task due to the miniaturization as well as the complexity of leading-edge products. ...

Coping with variability

A challenge most critical to analog IC design involves the variability of the individual devices built on the semiconductor chip. Unlike board-level circuit design which permits the designer to select devices that have each been tested and binned according to value, the device values on an IC can vary widely which are uncontrollable by the designer. For example, some IC resistors can vary ±20% and β of an integrated BJT can vary from 20 to 100. To add to the design challenge, device properties often vary between each processed semiconductor wafer. Device properties can even vary significantly across each individual IC due to doping gradients. The underlying cause of this variability is that many semiconductor devices are highly sensitive to uncontrollable random variances in the process. Slight changes to the amount of diffusion time, uneven doping levels, etc. can have large effects on device properties. Look up Bin on Wiktionary, the free dictionary Bin can refer to: Any container for storing any kind of material or items, usually with a large opening at the top so that contents can easily be removed, often with a lid. ... A bipolar junction transistor (BJT) is a type of transistor. ... In vector calculus, the gradient of a scalar field is a vector field which points in the direction of the greatest rate of change of the scalar field, and whose magnitude is the greatest rate of change. ...

The design techniques necessary to reduce the effects of the device variation are:

• Using the ratios of resistors, which do match closely, rather than absolute resistor value.
• Using devices with matched geometrical shapes so they have matched variations.
• Making devices large so that statistical variations becomes an insignificant fraction of the overall device property.
• Segmenting large devices, such as resistors, into parts and interweaving them to cancel variations.
• Using common centroid device layout to cancel variations in devices which must match closely (such as the transistor differential pair of an op amp).

Fortunately for IC design, the absolute values of the devices are less critical than the identical matching of device performance. However, this fabrication variability forces certain design techniques and prevents the use of other design techniques familiar to the board-level designer. An operational amplifier or op-amp is an electronic circuit module (normally built as an integrated circuit, but occasionally with discrete transistors or vacuum tubes) which has a non-inverting input (+), an inverting input (-) and one output. ...

Tools and vendors

Some of the popular electronic design automation tools are circuit simulation, logic synthesis, place and route, and design rule checking. The four largest companies^{[citation needed]} selling these tools are Cadence, Synopsys, Mentor Graphics, and Magma Design Automation. PCB Layout Program Electronic design automation (EDA) is the category of tools for designing and producing electronic systems ranging from printed circuit boards (PCBs) to integrated circuits. ... “Spiciness” redirects here. ... Logic synthesis is a process by which an abstract form of desired circuit behavior (typically register transfer level (RTL) or behavioral) is turned into a design implementation in terms of logic gates. ... Place and Route is a stage in design of: Printed circuit boards at which components are graphically placed on the board and the wires drawn between them. ... Design Rule Checking or Check(s) (DRC) is the area of Electronic Design Automation software that determines whether a particular chip design satisfies a series of recommended parameters called Design Rules. ... Cadence Design Systems, Inc (Nasdaq: CDN, NYSE: CDN) is an electronic design automation (EDA) software company, founded in 1988 by the merger of SDA Systems and ECAD. As of 2004, Cadence is the worlds largest supplier of electronic design technologies and engineering services. ... Synopsys, Inc. ... Mentor Graphics, Inc (NASDAQ: MENT) is a US-based multinational corporation dealing in electronic design automation (EDA) for electrical engineering and electronics, as of 2004, ranked third in the EDA industry. ... Magma Design Automation, Inc (Nasdaq: LAVA) is an electronic design automation (EDA) software company, founded in 1997, located in Santa Clara, California. ...

See also

• Electronic design automation
• IEEE Transactions on Computer-Aided Design of Integrated Circuits and Systems

PCB Layout Program Electronic design automation (EDA) is the category of tools for designing and producing electronic systems ranging from printed circuit boards (PCBs) to integrated circuits. ... IEEE Transactions on Computer-Aided Design of Integrated Circuits and Systems, often abbreviated IEEE TCAD or IEEE Transactions on CAD, is a technical journal devoted to the design, analysis, and use of computer programs that aid in the design of integrated circuits and systems. ...

References

• Electronic Design Automation For Integrated Circuits Handbook, by Lavagno, Martin, and Scheffer, ISBN 0-8493-3096-3 A survey of the field of electronic design automation, one of the main enablers of modern IC design.

PCB Layout Program Electronic design automation (EDA) is the category of tools for designing and producing electronic systems ranging from printed circuit boards (PCBs) to integrated circuits. ...

External links

• CAD – IEEE Transactions on Computer-Aided Design of Integrated Circuits and Systems