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My name is chinthapatla yashwanth My parents Chinthapatla Prabhakar & chinthapatla Jayashree My hometown is Nagarkurnool. I did polytechnic after tenth grade. At the time, Inter joined everyone, but I joined the polytechnic ece branch to be specific. After completing polytchnic I joined b.tech, I am currently doing m.tech. This is the detail of my read. Blogger will help me to share more with you in the future. Thanks
My name is chinthapatla yashwanth My parents Chinthapatla Prabhakar & chinthapatla Jayashree My hometown is Nagarkurnool. I did polytechnic after tenth grade. At the time, Inter joined everyone, but I joined the polytechnic ece branch to be specific. After completing polytchnic I joined b.tech, I am currently doing m.tech. This is the detail of my read. Blogger will help me to share more with you in the future. Thanks
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| Yashwanth in 2019 Journal provides a dynamic high-quality international forum for original papers and tutorials by academic, industrial, and other scholarly contributors in VLSI Design. The development of microelectronics spans a time which is even lesser than the average life expectancy of a human, and yet it has seen as many as four generations. Early 60’s saw the low density fabrication processes classified under Small Scale Integration (SSI) in which transistor count was limited to about 10. This rapidly gave way to Medium Scale Integration in the late 60’s when around 100 transistors could be placed on a single chip. It was the time when the cost of research began to decline and private firms started entering the competition in contrast to the earlier years where the main burden was borne by the military. Transistor-Transistor logic (TTL) offering higher integration densities outlasted other IC families like ECL and became the basis of the first integrated circuit revolution. It was the production of this family that gave impetus to semiconductor giants like Texas Instruments, Fairchild and National Semiconductors. Early seventies marked the growth of transistor count to about 1000 per chip called the Large-Scale Integration. By mid-eighties, the transistor counts on a single chip had already exceeded 1000 and hence came the age of Very Large Scale Integration or VLSI. Though many improvements have been made and the transistor count is still rising, further names of generations like ULSI are generally avoided. It was during this time when TTL lost the battle to MOS family owing to the same problems that had pushed vacuum tubes into negligence, power dissipation and the limit it imposed on the number of gates that could be placed on a single die. The second age of Integrated Circuits revolution started with the introduction of the first microprocessor, the 4004 by Intel in 1972 and the 8080 in 1974. Today many companies like Texas Instruments, Infineon, Alliance Semiconductors, Cadence, Synopsys, Celox Networks, Cisco, Micron Tech, National Semiconductors, ST Microelectronics, Qualcomm, Lucent, Mentor Graphics, Analog Devices, Intel, Philips, Motorola and many other firms have been established and are dedicated to the various fields in "VLSI" like Programmable Logic Devices, Hardware Descriptive Languages, Design tools, Embedded Systems etc. In 1980’s hold-over from outdated taxonomy for integration levels. Obviously influenced from frequency bands, i.e. HF, VHF, and UHF. Sources disagree on what is measured (gates or transistors) SSI – Small-Scale Integration (0-102) MSI – Medium-Scale Integration (102 -103) LSI – Large-Scale Integration (103 -105) VLSI – Very Large-Scale Integration (105 - 107) ULSI – Ultra Large-Scale Integration (>= 107) VLSI Technology, Inc. was a company which designed and manufactured custom and semi-custom ICs. The company was based in Silicon Valley, with headquarters at 1109 McKay Drive in San Jose, California. Along with LSI Logic, VLSI Technology defined the leading edge of the application-specific integrated circuit (ASIC) business, which accelerated the push of powerful embedded systems into affordable products. The company was founded in 1979 by a trio from Fairchild Semiconductor by way of Synertek - Jack Ballet to, Dan Floyd, and Gunnar Wetlesen - and by Doug Fairbairn of Xerox PARC and Lambda (later VLSI Design) magazine. Alfred J. Stein became the CEO of the company in 1982. Subsequently VLSI built its first fab in San Jose; eventually a second fab was built in San Antonio, Texas. VLSI had its initial public offering in 1983 and was listed on the stock market as (NASDAQ: VLSI). The company was later acquired by Philips and survives to this day as part of NXP Semiconductors. The first semiconductor chips held two transistors each. Subsequent advances added more and more transistors, and, as a consequence, more individual functions or systems were integrated over time. The first integrated circuits held only a few devices, perhaps as many as ten diodes, transistors, resistors and capacitors, making it possible to fabricate one or more logic gates on a single device. Now known retrospectively as small-scale integration (SSI), improvements in technique led to devices with hundreds of logic gates, known as medium-scale integration (MSI). Further improvements led to large-scale integration (LSI), i.e. systems with at least a thousand logic gates. Current technology has moved far past this mark and today's microprocessors have many millions of gates and billions of individual transistors. At one time, there was an effort to name and calibrate various levels of large- scale integration above VLSI. Terms like ultra-large-scale integration (ULSI) were used. But the huge number of gates and transistors available on common devices has rendered such fine distinctions moot. Terms suggesting greater than VLSI levels of integration are no longer in widespread use. As of early 2008, billion-transistor processors are commercially available. This is expected to become more commonplace as semiconductor fabrication moves from the current generation of 65 nm processes to the next 45 nm generations (while experiencing new challenges such as increased variation across process corners). A notable example is NVidia’s 280 series GPU. This GPU is unique in the fact that almost all of its 1.4 billion transistors are used for logic, in contrast to the Itanium, whose large transistor count is largely due to its 24 MB L3 cache. Current designs, as opposed to the earliest devices, use extensive design automation and automated logic synthesis to lay out the transistors, enabling higher levels of complexity in the resulting logic functionality. Certain high-performance logic blocks like the SRAM (Static Random-Access Memory) cell, however, are still designed by hand to ensure the highest efficiency (sometimes by bending or breaking established design rules to obtain the last bit of performance by trading stability) [citation needed]. VLSI technology is moving towards radical level miniaturization with introduction of NEMS technology. A lot of problems need to be sorted out before the transition is actually made.
Integration improves the design, lowers the parasitic, which means higher speed and lower power consumption and physically smaller. The Integration reduces manufacturing cost - (almost) no manual assembly. The course will cover basic theory and techniques of digital VLSI design in CMOS technology. Topics include: CMOS devices and circuits, fabrication processes, static and dynamic logic structures, chip layout, simulation and testing, low power techniques, design tools and methodologies, VLSI architecture. We use full-custom techniques to design basic cells and regular structures such as data-path and memory. There is an emphasis on modern design issues in interconnect and clocking. We will also use several case-studies to explore recent real-world VLSI designs (e.g. Pentium, Alpha, PowerPC Strong ARM, etc.) and papers from the recent research literature. On-campus students will design small test circuits using various CAD tools. Circuits will be verified and analyzed for performance with various simulators. Some final project designs will be fabricated and returned to students the following semester for testing. Very-large-scale integration (VLSI) is the process of creating integrated circuits by combining thousands of transistor-based circuits into a single chip. VLSI began in the 1970s when complex semiconductor and communication technologies were being developed. The microprocessor is a VLSI device. The term is no longer as common as it once was, as chips have increased in complexity into the hundreds of millions of transistors. The first semiconductor chips held one transistor each. Subsequent advances added more and more transistors, and, as a consequence, more individual functions or systems were integrated over time. The first integrated circuits held only a few devices, perhaps as many as ten diodes, transistors, resistors and capacitors, making it possible to fabricate one or more logic gates on a single device. Now known retrospectively as "small-scale integration" (SSI), improvements in technique led to devices with hundreds of logic gates, known as large-scale integration (LSI), i.e. systems with at least a thousand logic gates. Current technology has moved far past this mark and today's microprocessors have many millions of gates and hundreds of millions of individual transistors. At one time, there was an effort to name and calibrate various levels of large-scale integration above VLSI. Terms like Ultra-large- scale Integration (ULSI) were used. But the huge number of gates and transistors available on common devices has rendered such fine distinctions moot. Terms suggesting greater than VLSI levels of integration are no longer in widespread use. Even VLSI is now somewhat quaint, given the common assumption that all microprocessors are VLSI or better. As of early 2008, billion-transistor processors are commercially available, an example of which is Intel's Montecito Itanium chip. This is expected to become more commonplace as semiconductor fabrication moves from the current generation of 65 nm processes to the next 45 nm generations (while experiencing new challenges such as increased variation across process corners). Another notable example is NVIDIA’s 280 series GPU. This microprocessor is unique in the fact that its 1.4 Billion transistor count, capable of a teraflop of performance, is almost entirely dedicated to logic (Itanium's transistor count is largely due to the 24MB L3 cache). Current designs, as opposed to the earliest devices, use extensive design automation and automated logic synthesis to lay out the transistors, enabling higher levels of complexity in the resulting logic functionality. Certain high- performance logic blocks like the SRAM cell, however, are still designed by hand to ensure the highest efficiency (sometimes by bending or breaking established design rules to obtain the last bit of performance by trading stability). The original business plan was to be a contract wafer fabrication company, but the venture investors wanted the company to develop IC (Integrated Circuit) design tools to help fill the foundry. Thanks to its Caltech and UC Berkeley students, VLSI was an important pioneer in the electronic design automation industry. It offered a sophisticated package of tools, originally based on the 'lambda-based' design style advocated by Carver Mead and Lynn Conway. VLSI became an early vendor of standard cell (cell-based technology) to the merchant market in the early 80s where the other ASIC-focused company, LSI Logic, was a leader in gate arrays. Prior to VLSI's cell-based offering, the technology had been primarily available only within large vertically integrated companies with semiconductor units such as AT&T and IBM. VLSI's design tools eventually included not only design entry and simulation but eventually cell-based routing (chip compiler), a data path compiler, SRAM and ROM compilers and a state machine compiler. The tools were an integrated design solution for IC design and not just point tools, or more general-purpose system tools. A designer could edit transistor-level polygons and/or logic schematics, then run DRC and LVS, extract parasites from the layout and run Spice simulation, then back- annotate the timing or gate size changes into the logic schematic database. Characterization tools were integrated to generate Frame Maker Data Sheets for Libraries. VLSI eventually spun off the CAD and Library operation into Compass Design Automation, but it never reached IPO before it was purchased by Avanti Corp. VLSI's physical design tools were critical not only to its ASIC business, but also in setting the bar for the commercial EDA industry. When VLSI and its main ASIC competitor, LSI Logic, were establishing the ASIC industry, commercially- available tools could not deliver the productivity necessary to support the physical design of hundreds of ASIC designs each year without the deployment of a substantial number of layout engineers. The companies' development of automated layout tools was a rational "make because there's nothing to buy" decision. The EDA industry finally caught up in the late 1980s when Tangent Systems released its Tan Cell and Tan Gate products. In 1989, Tangent was acquired by Cadence Design Systems (founded in 1988). Unfortunately, for all VLSI's initial competence in design tools, they were not leaders in semiconductor manufacturing technology. VLSI had not been timely in developing a 1.0 µm manufacturing process as the rest of the industry moved to that geometry in the late 80s. VLSI entered a long-term technology partnership with Hitachi and finally released a 1.0 µm process and cell library (actually more of a 1.2 µm library with a 1.0 µm gate). As VLSI struggled to gain parity with the rest of the industry in semiconductor technology, the design flow was moving rapidly to a Verilog HDL and synthesis flow. Cadence acquired Gateway, the leader in Verilog hardware design language (HDL) and Synopsys was dominating the exploding field of design synthesis. As VLSI's tools were being eclipsed, VLSI waited too long to open the tools up to other fabrications and Compass Design Automation was never a viable competitor to industry leaders. Meanwhile, VLSI entered the merchant high speed static RAM (SRAM) market as they needed a product to drive the semiconductor process technology development. All the large semiconductor companies built high speed SRAMs with cost structures VLSI could never match. VLSI withdrew once it was clear that the Hitachi process technology partnership was working. ARM Ltd was formed in 1990 as a semiconductor intellectual property licensor, backed by Acorn, Apple and VLSI. VLSI became a licensee of the powerful ARM processor and ARM finally funded processor tools. Initial adoption of the ARM processor was slow. Few applications could justify the overhead of an embedded 32- bit processor. In fact, despite the addition of further licensees, the ARM processor enjoyed little market success until they developed the novel 'thumb' extensions. Ericsson adopted the ARM processor in a VLSI chipset for its GSM handset designs in the early 1990s. It was the GSM boost that is the foundation of ARM the company/technology that it is today. Only in PC chipsets, did VLSI dominate in the early 90s. This product was developed by five engineers using the 'Mega cells" in the VLSI library that led to a business unit at VLSI that almost equaled its ASIC business in revenue. VLSI eventually ceded the market to Intel because Intel was able to package-sell its processors, chipsets, and even board level products together. VLSI also had an early partnership with PMC, a design group that had been nurtured of British Columbia Bell. When PMC wanted to divest its semiconductor intellectual property venture, VLSI's bid was beaten by a creative deal by Sierra Semiconductor. The telecom business unit management at VLSI opted to go it alone. PMC Sierra became one of the most important telecom ASSP vendors. Scientists and innovations from the 'design technology' part of VLSI found their way to Cadence Design Systems (by way of Redwood Design Automation). Compass Design Automation (VLSI's CAD and Library spin-off) was sold to Avant! Corporation, which itself was acquired by Synopsys. |
