Analog VLSI Design - What Happened Last Year

by Paul Latham

Last year was the first year that analog VLSI was offered at UNH. EE992 was offered in the fall and EE796/896 in the spring. EE992 is a graduate level course based on larger projects with emphasis on chip level techniques. EE796/EE896 is an introductory version with smaller projects and emphasis on basic circuit design. All of the projects involved designing integrated circuits using the  Design Automation Laboratory (DAL) CAD facilities. All of the projects are now being fabricated using MOSIS services. The finished projects will be used in next year's classes and can also be used for independent study.

Many things are best learned by doing. Integrated circuit (IC) design is one of them. This is why the central theme for both classes is class projects. With these projects, the student goes through the process of design and layout of an IC. The projects are selected by a combination of student interest and practical time/complexity limitations.

Many very instructive and realistic class projects were chosen. Projects include: a pipelined ADC, a switched capacitor delta sigma modulator, a switched current filter, a phase lock loop, a CMOS image sensor, and others.

Many of these projects are the basis of cutting edge ICs available today. For example, pipelined ADCs are used in many advanced disc drives in what is called a PRML read channel. The ADC in that application converts the analog recording signal into data. Delta sigma modulators are used in almost all CD players, DVD players, and PC sound systems. Delta sigma modulators are used to convert analog signals to and from digital data. CMOS image sensors are the new competition to CCD image sensors used in camcorders.

This year we hope to spend some lab time evaluating some of the prior year's projects. This will allow students to obtain valuable debugging experience. Next year's projects may include continuous time integrated filters, power amplifiers, switch mode power converters, adiabatic logic, and possibly active pixel CMOS image sensors. If you have any project ideas please contact me.

"Analog Integrated Circuit Design," by David A. Johns and Ken Martin, was an excellent book covering analog CMOS design. This year I hope to change to "CMOS: Circuit Design, Layout, and Simulation", by R. Jacob Baker, Harry W. Li, and David E. Boyce. This new book has a better practical feel. Also, it covers transistor level logic design. Most of today's "analog" chips have a lot of logic in them. David E. Boyce is the author of LASI, a shareware IC layout tool.

In addition to the DAL facilities, I plan to make available PC based CAD tools. These tools will include both IC design and layout tools. This should enable students to work at home as well as on campus.

I hope to offer the spring session of EE796/896 as an Internet class using Far View. This is done in hopes of allowing more off-campus students to attend.