| Category | Difficulty |
|---|---|
| HW | 3 |
| Projects | 8 |
This class provides an overview of RFICs - radio-frequency integrated circuits - at the transistor-level.
It covers the basics of RF communication systems, starting with a system-level overview of transceivers before diving deeper into the analysis of the building blocks of a transceiver. Power amplifiers, low noise amplifiers, mixers, and more are discussed, with several topologies and design examples covered. Through the projects, you learn how to balance tradeoffs for RFIC designs.
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 18-320 (Microelectronic Circuits) and 18-623 (Analog Integrated Circuit Design). 18-320 is also a prerequisite for 18-623, so you should absolutely have 18-320 completed before attempting 18-723. Although 18-623 is listed as a prerequisite, there are students who have taken both 18-623 and 18-723 together and succeeded. However, this relies upon having strong circuit design fundamentals from 18-320. Also, having 18-623 already completed will mean that you are more familiar with analog IC topologies (common source amplifiers, differential pairs, etc.) and the Cadence software. Thus, though you can take 18-623 with 18-723, it is for the best that you learn 18-623 thoroughly before taking 18-723.
There is only a single homework for the class, and no exams. The homework is in the first few weeks of the course, and correspondingly focuses on concepts in those lectures. It does not involve any simulation -- only mathematical analysis. Hopefully, it should not take too long, but be sure to go to office hours if you need to review those concepts.
This course is primarily driven by its projects, of which there are three. There are two labs in the first month of the course that will help familiarize you with Cadence, as well as the specific RF analysis tools used for this course. However, these labs are guided and should not take too much time.
Note that starting from the second month of the course onwards, the projects begin in earnest, with a project milestone every week or so. This can make it fairly difficult to keep pace with the lecture concepts, since the projects move very quickly. Be sure to use the first few weeks of class to keep pace with the lectures so that you are ready to tackle the projects, once they begin.
The projects are done in groups of two or three. These projects involve the use of Cadence for simulation and analysis of your IC designs. 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, the projects will have design reviews and presentations, which will allow you to get feedback on your approach as you work through your implementation. Use this time to get as much advice as possible!
This project builds a power amplifier, which drives an antenna to transmit RF signals for the transceiver with high gain.
In this project, you are provided the basic matching networks for the input and output of the power amplifier. You are also given the basic topology in Cadence; the main task is to go through the mathematical analysis to choose the correct component values. Additionally, you are supposed to do two designs - a single transistor design and a cascode configuration.
Because you are supposed to do two designs, it might make sense for one person to pick the single transistor design and the other to do the cascode design. The important thing is to work through and understand the mathematical analysis before trying out the implementation. Be sure to seek feedback from the professor and TA to get any clarification needed before simulating.
This project has you build a low noise amplifier, which amplifies a low-noise signal without degrading the signal-to-noise ratio. These appear at the receiver of an RF transceiver system.
For this project, you are given a basic topology to start with, but you will need to figure out the load network as well as component values for the matching networks. You are given tasks to help guide your design to produce an implementation that satisfies all of the constraints.
A good idea would be to divide the tasks between you and your teammate, so you both can do some mathematical analysis and get feedback. Then, you can both put together the implementation based on your analyses and components chosen.
This project focuses on building a frequency mixer, which takes in two input signals and outputs a signal of a new frequency. The mixer consists of a buffer for the local oscillator (LO) signal, and the mixer core which takes in the LO signal and the RF input to produce the intermediate frequency (IF) output signal.
This is perhaps the most difficult project of the three, since there are several components to the mixer that affect the performance specifications. Like the previous projects, you will have to spend some time going over your design to ensure that you meet all specifications.
Similar to the previous projects, work with your teammate to split up portions of the design, test them individually, and then integrate together. The mixer project lends itself to one teammate working on the LO buffer and the other working on the mixer core. You can design testbenches so that you can test both components with ideal inputs and outputs, before putting them together.
- Course Description
- Course textbook: RF Microelectronics, 2nd Edition
- Additional text 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 18723. Prof. Razavi has developed some amazing resources for learning IC design.