| Category | Difficulty |
|---|---|
| HW | 7 |
| Projects | 8 |
| Exams | 6 |
This class provides an overview of analog integrated circuits, covering a number of IC designs and techniques at the transistor-level.
It covers MOSFET modes of operation, as well as its various applications. The class then shows a number of amplifier topologies and their use cases. It also covers the differential pair and the operational amplifier in great detail, among other topologies. It focuses on how to analyze and design analog circuits to meet certain specifications and constraints, showing the tradeoff between these goals.
Please note that this guide was written from Fall 2021; the assignments and material for the course may change slightly in future offerings of the course.
The official prerequisites for this course are 18-290 (Signals and Systems) and 18-320 (Microelectronic Circuits). That said, 18-290 is not a stiff prerequisite, since the concepts from that course are introduced and reviewed before they are used in 18-623. More specifically, you will see frequency response and feedback control in the context of op-amp design, but there is a lecture dedicated to reviewing these concepts first. However, 18-320 is a much more important prerequisite; familiarity with transistors and circuit design at the level of 18-320 will be very helpful for 18-623.
You will have around 5-6 homeworks throughout the semester. They involve both conceptual questions which require you to work through circuits and calculations on paper, as well as some simulation-based problems. The homeworks can be challenging but, as with most classes, be sure to start early and utilize office hours. The textbook may also be very helpful to review relevant concepts, although it can be quite dense in its analysis.
The TAs will hold lab sessions on Fridays, some of which are dedicated to helping you out with the homework. Be sure to attend those, and come with lots of questions! That is a great time to get some clarification for the homework, as well as lecture concepts in general.
Ultimately, the homeworks have a lower weight on your grade, relative to the projects and exams. However, you should still give a good effort on them -- be sure to go back and learn what you did not understand fully when doing the homework. This will help you when it comes time to tackle the projects and exams.
There are two exams in the course. The first exam covers roughly the first ten lectures, and the second exam covers roughly the next ten lectures (though the second exam depends upon material from the first).
The exams are very reflective of what is covered in the lectures and on the homeworks. As you go through each lecture, be sure to take notes on the different examples covered. Additionally, be sure to spend time reviewing the homeworks after you have completed them. Both will help prepare you for what is covered on the exams.
You may also find the textbook by Razavi, mentioned in the Resources section, to be very useful for practice problems similar to the exam problems. Lastly, make sure that you review your circuit fundamentals; knowing how to apply those skills to analyze circuits quickly can make a huge difference in finishing the exam on time.
The exams are similar in weight as the projects for your grade, so it is advised to prepare well for them.
The projects are the "meat" of this course. Through these projects, you will learn how to use Cadence for circuit simulation and layout, as well as how to approach an analog IC design task.
Consequently, you will likely spend a significant amount of time on the projects -- but hopefully, you will be learning through doing. You will be asked to meet a number of design specifications for both projects; the challenge comes in meeting all specifications, since there are often key tradeoffs in design.
The projects are done in pairs of two. Since you are working in Cadence, it can be tricky to divide responsibilities, but you should still be able to break the projects into subcomponents that you can both work on and then integrate. Additionally, both projects will have a design review, which will allow you to get feedback on your approach before you begin your implementation. Use this time to get as much advice as possible!
You will have a few short lab sessions that will catch you up on the basics of Cadence simulation and layout. However, these only show you the very basics of Cadence; you'll really start to become familiar with its tools through working on the projects. Be sure to go to office hours frequently to get help with Cadence, since you do not want to be struggling with the software once it comes time for the projects.
Also, try and figure out your workflow for Cadence early on; some folks may find it convenient to access the Cadence software on their computer, but you might find that it introduces a lot of latency with the software. If your computer is having a hard time accessing Cadence remotely, then you may just want to do your work on the physical computers that run Cadence in the labs.
Note that the projects are done over roughly the course of one month each. This may sound like a lot of time, but you will also have homeworks and exams in the course during this time - the earlier you start on the projects, the better!
This project has you build a transimpedance amplifier, which is a current-to-voltage converter. The TIA is broken into three stages: an input stage to convert the input current to a voltage, a gain stage to amplify the voltage, and an output stage to provide a buffer for the output signal. You will also create biasing circuitry for the TIA, as well as testbenches to test each part of the circuit.
Interestingly enough, you may find the first project to be much more difficult than the second project. This is because you are likely still going to be learning the basics of Cadence, as well as developing your understanding of amplifier topologies. Also, although you are given a basic topology for the TIA design, you will need to revise the design significantly in order to meet the desired specifications. As you go through your design process, be sure to go to office hours to get feedback. The course staff can help step you through the process so that you understand how to approach IC design.
That said, this project lends itself well to a divide-and-conquer approach. You and your teammate can decide who takes each component of the TIA. Then, you can slowly put the pieces together. Before you begin your work in Cadence, though, be sure to spend a large amount of time on the design. You should work out the different characteristics of your circuit before implementing it in Cadence. Use the design review to get good feedback from the professor and TAs.
This project has you build an op-amp, which you have likely used as a building block in a larger circuit from earlier electronics classes. The op-amp is broken into two stages: a differential pair stage and a high-gain amplifier stage. Like the previous project, you will also create biasing circuitry for the op-amp; testbenches are also a good idea.
You may find this project to be a bit easier than the previous one. This is because by this point, you have learned the tools of Cadence. Additionally, some of the lectures from the middle of the class actually step through how to design an op-amp to meet certain specifications. You should definitely use these slides as an aid in designing your own op-amp for this project. Like the previous project, if you are having trouble in your design approach, go to office hours! The course staff is happy to help push you in the right direction.
Similar to the previous project, work with your teammate to split up portions of the design, test them individually, and then integrate together. You will also need to do layout for this project, but that should be saved for after you have finalized your simulations; hopefully it should take much less time than the circuit design and simulation.
- Course Description
- Course textbook: Analysis and Design of Analog Integrated Circuits, 5th Edition
- Additional text by Razavi that may be useful: Design of Analog CMOS Integrated Circuits, 2nd Edition
- Professor Behzad Razavi's lectures: this playlist contains lectures on a number of topics that are relevant to 18623. Prof. Razavi has developed some amazing resources for learning IC design.