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Principle Of Logical Effort
The method of logical effort, a term coined by Ivan Sutherland and Bob Sproull in 1991, is a straightforward technique used to estimate delay in a CMOS circuit. Used properly, it can aid in selection of gates for a given function (including the number of stages necessary) and sizing gates to achieve the minimum delay possible for a circuit. Derivation of delay in a logic gate Delay is expressed in terms of a basic delay unit, ''Ï„'' = ''3RC'', the delay of an inverter driving an identical inverter without any additional capacitance added by interconnects or other loads; the unitless number associated with this is known as the normalized delay. (Some authors prefer define the basic delay unit as the fanout of 4 delay—the delay of one inverter driving 4 identical inverters). The absolute delay is then simply defined as the product of the normalized delay of the gate, ''d'', and ''Ï„'': :d_ = d \cdot \tau In a typical 600-nm process ''Ï„'' is about 50 ps. For a 250-nm process, ''Ï ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ivan Sutherland
Ivan Edward Sutherland (born May 16, 1938) is an American computer scientist and Internet pioneer, widely regarded as a pioneer of computer graphics. His early work in computer graphics as well as his teaching with David C. Evans in that subject at the University of Utah in the 1970s was pioneering in the field. Sutherland, Evans, and their students from that era developed several foundations of modern computer graphics. He received the Turing Award from the Association for Computing Machinery in 1988 for the invention of Sketchpad, an early predecessor to the sort of graphical user interface that has become ubiquitous in personal computers. He is a member of the National Academy of Engineering, as well as the National Academy of Sciences among many other major awards. In 2012 he was awarded the Kyoto Prize in Advanced Technology for "pioneering achievements in the development of computer graphics and interactive interfaces". Biography Sutherland's father was from New Zeal ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bob Sproull
Robert Fletcher "Bob" Sproull (born c. 1945) is an American computer scientist, who worked for Oracle Corporation where he was director of Oracle Labs in Burlington, Massachusetts. He is currently an adjunct professor at the College of Information and Computer Sciences, at the University of Massachusetts Amherst. Biography While working towards his B.A. in physics at Harvard College in 1967, Sproull met Ivan Sutherland. Together, they worked on head-mounted displays, which led the way for 3-dimensional virtual reality. Sproull received his master's degree in Computer Science from Stanford University in 1970, and Doctorate in Computer Science from Stanford in 1977. Sproull worked as a researcher for Xerox Palo Alto Research Center from December 1973 to August 1977. While at Xerox PARC, he worked on the design of the Alto personal computer, the first laser printers, page description languages and the initial PC-type operating systems. In 1973, Sproull and William M. Newman ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Delay Calculation
Delay calculation is the term used in integrated circuit design for the calculation of the gate delay of a single logic gate and the wires attached to it. By contrast, static timing analysis computes the delays of entire paths, using delay calculation to determine the delay of each gate and wire. There are many methods used for delay calculation for the gate itself. The choice depends primarily on the speed and accuracy required: :*Circuit simulators such as SPICE may be used. This is the most accurate, but slowest, method. :*Two dimensional tables are commonly used in applications such as logic synthesis, placement and routing. These tables take an output load and input slope and generate a circuit delay and output slope. The values of the tables are usually computed using circuit simulators in a procedure referred to as ''characterization'' or ''standard cell characterization''. A common file format for storing the lookup tables is the ''Liberty'' format. :*A very simple mo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
CMOS
Complementary metal–oxide–semiconductor (CMOS, pronounced "sea-moss", ) is a type of metal–oxide–semiconductor field-effect transistor (MOSFET) fabrication process that uses complementary and symmetrical pairs of p-type and n-type MOSFETs for logic functions. CMOS technology is used for constructing integrated circuit (IC) chips, including microprocessors, microcontrollers, memory chips (including CMOS BIOS), and other digital logic circuits. CMOS technology is also used for analog circuits such as image sensors (CMOS sensors), data converters, RF circuits (RF CMOS), and highly integrated transceivers for many types of communication. The CMOS process was originally conceived by Frank Wanlass at Fairchild Semiconductor and presented by Wanlass and Chih-Tang Sah at the International Solid-State Circuits Conference in 1963. Wanlass later filed US patent 3,356,858 for CMOS circuitry and it was granted in 1967. commercialized the technology with the trademark "COS-MO ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fanout Of 4
In digital electronics, Fan-out of 4 is a measure of time used in digital CMOS technologies: the gate delay of a component with a fan-out of 4. Fan out = Cload / Cin, where :Cload = total MOS gate capacitance driven by the logic gate under consideration :Cin = the MOS gate capacitance of the logic gate under consideration As a delay metric, one FO4 is the delay of an inverter, driven by an inverter 4x smaller than itself, and driving an inverter 4x larger than itself. Both conditions are necessary since input signal rise/fall time affects the delay as well as output loading. FO4 is generally used as a delay metric because such a load is generally seen in case of tapered buffers driving large loads, and approximately in any logic gate of a logic path sized for minimum delay. Also, for most technologies the optimum fanout for such buffers generally varies from 2.7 to 5.3. A fan out of 4 is the answer to the canonical problem stated as follows: Given a fixed size inverter, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Parasitic Delay
Parasitism is a close relationship between species, where one organism, the parasite, lives on or inside another organism, the host, causing it some harm, and is adapted structurally to this way of life. The entomologist E. O. Wilson has characterised parasites as "predators that eat prey in units of less than one". Parasites include single-celled protozoans such as the agents of malaria, sleeping sickness, and amoebic dysentery; animals such as hookworms, lice, mosquitoes, and vampire bats; fungi such as honey fungus and the agents of ringworm; and plants such as mistletoe, dodder, and the broomrapes. There are six major parasitic strategies of exploitation of animal hosts, namely parasitic castration, directly transmitted parasitism (by contact), trophicallytransmitted parasitism (by being eaten), vector-transmitted parasitism, parasitoidism, and micropredation. One major axis of classification concerns invasiveness: an endoparasite lives inside the host' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stage Effort
Stage or stages may refer to: Acting * Stage (theatre), a space for the performance of theatrical productions * Theatre, a branch of the performing arts, often referred to as "the stage" * ''The Stage'', a weekly British theatre newspaper * Stages Repertory Theatre, a theatre company in Houston, Texas Music * Stage, an American band featuring Ryan Star * ''Stage'', a 2002 book and DVD documenting Britney Spears' Dream Within a Dream Tour Albums * ''Stage'' (David Bowie album), 1978 * ''Stage'' (Great White album), 1995 * ''Stage'' (Keller Williams album), 2004 * ''Stage'', by Mónica Naranjo, 2009 * ''The Stage'' (album), by Avenged Sevenfold, or the title song (see below), 2016 * ''Stages'' (Cassadee Pope album), 2019 * ''Stages'' (Elaine Paige album), 1983 * ''Stages'' (Eric Clapton album), 1993 * ''Stages'' (Jimi Hendrix album), 1991 * ''Stages'' (Josh Groban album), 2015 * ''Stages'' (Melanie C album), 2012 * ''Stages'' (Triumph album), 1985 * ''Stages'' (Ve ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Power MOSFET
A power MOSFET is a specific type of metal–oxide–semiconductor field-effect transistor (MOSFET) designed to handle significant power levels. Compared to the other power semiconductor devices, such as an insulated-gate bipolar transistor (IGBT) or a thyristor, its main advantages are high switching speed and good efficiency at low voltages. It shares with the IGBT an isolated gate that makes it easy to drive. They can be subject to low gain, sometimes to a degree that the gate voltage needs to be higher than the voltage under control. The design of power MOSFETs was made possible by the evolution of MOSFET and CMOS technology, used for manufacturing integrated circuits since the 1960s. The power MOSFET shares its operating principle with its low-power counterpart, the lateral MOSFET. The power MOSFET, which is commonly used in power electronics, was adapted from the standard MOSFET and commercially introduced in the 1970s. The power MOSFET is the most common power semicond ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
CMOS Inverter
In digital logic, an inverter or NOT gate is a logic gate which implements logical negation. It outputs a bit opposite of the bit that is put into it. The bits are typically implemented as two differing voltage levels. Description The NOT gate outputs a zero when given a one, and a one when given a zero. Hence, it inverts its inputs. Colloquially, this inversion of bits is called "flipping" bits. As with all binary logic gates, other pairs of symbols such as true and false, or high and low may be used in lieu of one and zero. It is equivalent to the logical negation operator (¬) in mathematical logic. Because it has only one input, it is a unary operation and has the simplest type of truth table. It is also called the complement gate because it produces the ones' complement of a binary number, swapping 0s and 1s. The NOT gate is one of three basic logic gates from which any Boolean circuit may be built up. Together with the AND gate and the OR gate, any function in binary m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Elmore Delay
Elmore delay is a simple approximation to the delay through an RC network in an electronic system. It is often used in applications such as logic synthesis, delay calculation, static timing analysis, placement and routing, since it is simple to compute (especially in tree structured networks, which are the vast majority of signal nets within ICs) and is reasonably accurate. Even where it is not accurate, it is usually faithful, in the sense that reducing the Elmore delay will almost always reduce the true delay, so it is still useful in optimization. Elmore delay can be thought of in several ways, all mathematically identical. *For tree structured networks, find the delay through each segment as the R (electrical resistance) times the downstream C (electrical capacitance). Sum the delays from the root to the sink. *Assume the output is a simple exponential, and find the exponential that has the same integral as the true response. This is also equivalent to ''moment matching' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Digital Electronics
Digital electronics is a field of electronics involving the study of digital signals and the engineering of devices that use or produce them. This is in contrast to analog electronics and analog signals. Digital electronic circuits are usually made from large assemblies of logic gates, often packaged in integrated circuits. Complex devices may have simple electronic representations of Boolean logic functions. History The binary number system was refined by Gottfried Wilhelm Leibniz (published in 1705) and he also established that by using the binary system, the principles of arithmetic and logic could be joined. Digital logic as we know it was the brain-child of George Boole in the mid 19th century. In an 1886 letter, Charles Sanders Peirce described how logical operations could be carried out by electrical switching circuits.Peirce, C. S., "Letter, Peirce to A. Marquand", dated 1886, '' Writings of Charles S. Peirce'', v. 5, 1993, pp. 541–3. GooglPreview See Burks, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
