Page 12 Friday, January 18, 2002 8:58 AM in .NET Integration EAN13 in .NET Page 12 Friday, January 18, 2002 8:58 AM Page 12 Friday, January 18, 2002 8:58 AM using .net vs 2010 toprint ean-13 for web,windows application Java Projects INTRODUCTION 1 . the first practical MO EAN-13 Supplement 2 for .NET S integrated circuits were implemented in PMOS-only logic and were used in applications such as calculators. The second age of the digital integrated circuit revolution was inaugurated with the introduction of the first microprocessors by Intel in 1972 (the 4004) [Faggin72] and 1974 (the 8080) [Shima74].

These processors were implemented in NMOS-only logic, which has the advantage of higher speed over the PMOS logic. Simultaneously, MOS technology enabled the realization of the first highdensity semiconductor memories. For instance, the first 4Kbit MOS memory was introduced in 1970 [Hoff70].

These events were at the start of a truly astounding evolution towards ever higher integration densities and speed performances, a revolution that is still in full swing right now. The road to the current levels of integration has not been without hindrances, however. In the late 1970s, NMOS-only logic started to suffer from the same plague that made high-density bipolar logic unattractive or infeasible: power consumption.

This realization, combined with progress in manufacturing technology, finally tilted the balance towards the CMOS technology, and this is where we still are today. Interestingly enough, power consumption concerns are rapidly becoming dominant in CMOS design as well, and this time there does not seem to be a new technology around the corner to alleviate the problem. Although the large majority of the current integrated circuits are implemented in the MOS technology, other technologies come into play when very high performance is at stake.

An example of this is the BiCMOS technology that combines bipolar and MOS devices on the same die. BiCMOS is used in high-speed memories and gate arrays. When even higher performance is necessary, other technologies emerge besides the already mentioned bipolar silicon ECL family Gallium-Arsenide, Silicon-Germanium and even superconducting technologies.

These technologies only play a very small role in the overall digital integrated circuit design scene. With the ever increasing performance of CMOS, this role is bound to be further reduced with time. Hence the focus of this textbook on CMOS only.

. Issues in Digital Inte grated Circuit Design Integration density and performance of integrated circuits have gone through an astounding revolution in the last couple of decades. In the 1960s, Gordon Moore, then with Fairchild Corporation and later cofounder of Intel, predicted that the number of transistors that can be integrated on a single die would grow exponentially with time. This prediction, later called Moore s law, has proven to be amazingly visionary [Moore65].

Its validity is best illustrated with the aid of a set of graphs. Figure 1.2 plots the integration density of both logic IC s and memory as a function of time.

As can be observed, integration complexity doubles approximately every 1 to 2 years. As a result, memory density has increased by more than a thousandfold since 1970. An intriguing case study is offered by the microprocessor.

From its inception in the early seventies, the microprocessor has grown in performance and complexity at a steady and predictable pace. The transistor counts for a number of landmark designs are collected in Figure 1.3.

The million-transistor/chip barrier was crossed in the late eighties. Clock frequencies double every three years and have reached into the GHz range. This is illus-. Page 13 Friday, January 18, 2002 8:58 AM Section 1.2 Issues in Digital Integrated Circuit Design 64 Gbits 1010 109 108 Number of bits per chip 256 Mbits 107 106 105 104 64 Mbits *0.08 m Human memory Human memory Human DNA Human DNA 4 Gbits 1 Gbits 0.15 m 0.15-0.2 m 0.25-0.3 m 0.35-0.4 m 0.5-0.6 m Book Book 16 Mbits 4 Mbits 0.7-0.8 m 1.0-1.2 m 1 Mbits 256 Kbits 1.6-2.4 m 64 Kbits Encyclopedia Encyclopedia 2 hrs CD Audio 2 hrs CD Audio 30 sec HDTV 30 sec HDTV Page Page 1970 1980 1990 Year 2000 2010 (a) Trends in logic IC complexity Figure 1.2 (b) Trends in memory complexity Evolution of integration complexity of logic ICs and memories as a function of time. trated in Figure 1.4, which plots the microprocessor trends in terms of performance at the beginning of the 21st century. An important observation is that, as of now, these trends have not shown any signs of a slow-down.

It should be no surprise to the reader that this revolution has had a profound impact on how digital circuits are designed. Early designs were truly hand-crafted. Every transistor was laid out and optimized individually and carefully fitted into its environment.

This is adequately illustrated in Figure 1.5a, which shows the design of the Intel 4004 microprocessor. This approach is, obviously, not appropriate when more than a million devices have to be created and assembled.

With the rapid evolution of the design technology, time-to-market is one of the crucial factors in the ultimate success of a component..
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