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analog cmos circuit


CMOS integrated technology has come to dominate analog, digital, and mixed-signal electronic circuit design. Continued improvements in device performance have overcome this traditional CMOS obstacle. The pressure to reduce system cost has favored all-CMOS solutions over systems that mix bipolar and CMOS chips or use Bi-CMOS technology 1 . In current design practice, bipolar devices are usually found only in very-high performance wired and wireless designs where extreme
device specifications — high ft, low noise, and superior matching — require high-yielding,power-efficient components
Similarly, compound semiconductor devices are used only in the case of very high speed circuits in applications running at 10GHz. At the same time, changing design practices have revolutionized the way that electronic system design is performed. At the board level, small-scale integrated circuits such as operational amplifiers have replaced discrete components because of their reduced cost. With increasing frequency these board-level designs are themselves replaced by very complex application-specific parts that are designed especially for mass-produced applications. Often these components are designed as intellectual property cores which are reused on several different chips, especially large chips that incorporate an entire System on a Chip.
One might expect that this trend would remove many engineers from the process of transistor-level design, with only a few large semiconductor companies providing pre-designed and pre-manufactured components. However, the emergence of silicon foundries has made chip-level design more accessible to engineers than ever before. These foundries act as manufacturing services for a large number of customers, making it possible for even small companies to create custom chips without the expense of a fabrication facility. Most of these foundries support only CMOS, reinforcing its dominance in electronic design.
We believe that electronics courses in undergraduate Electrical and Computer Engineering curricula must adapt to this new landscape. Specifically, these courses must follow the transition from bipolar to CMOS devices and provide exposure to transistor-level design at the chip level. To do this, the laboratory component of such a course must provide students with exposure to design at the integrated circuit level as well as with discrete components and high-level building blocks such as operational amplifiers.
Few good projects for students
Analog Multiplier using MOSFETs in the Triode Region
· Charge Pump for an IC Phase-Locked Loop (PLL)
· Low Voltage CMOS Bootstrapped Switch for a Sample-and-Hold Circuit
· Operational Amplifier with Cascode Output Stage
· Operational Amplifier with Class AB Output Stage
· Operational Amplifier with Constant gm Biasing
· High-Speed CMOS Phase Detector with Deadband Suppression for an IC PLL
· Ring-Oscillator based Voltage-Controlled Oscillator Design for an IC PLL