- RFIC design involves a lot of analog design which is easy to miss when you are lost in RF/mm-Wave world. What we do involves 60% analog and 40% RF design.
- Skills you need in addition to RF/mm-Wave skillset to ace RFIC interview:
- Small Signal Analysis
- Current and Voltage References
- Single and Multistage Differential Amplifiers, OTAs
- Frequency Response of Amplifiers
- Noise analysis
- Feedback, Stability Analysis
- Inverters, Level Shifters, Muxes, Switches, Combinational Login etc.
- Systematic Layout, Symmetry, Guard Rings, Shileding, Floor Planning
- We learn more Microsoft Excel than circuit design (maybe a sad truth) but data collection, analysis and automation is very important in time management and Excel would be a big help.
- In a big compnay, there are lots and lots of teams for every small task so that you focus on what you are good at:
- System team (budgets specs)
- Design team (that’s you most probably)
- Layout team (someone else does it, you guide them, you can also do if you have time…
- EM team (inductors, routings, baluns etc. you give them specs they design/optimize it
- Verification team (does RTL modelling, AMS simulations etc.)
- Reliability team (electromigration, aging, breakdown concerns)
- Process team (sets up PDKs, helps you with process)
- Bench team (sets up measurement bench and related automation)
- Test team (collects and analyze measurement data for you)
- Techncians (general purpose hardware support)
- And many more!
- Industry circuits are not descended from God:
- When we are student, we think what we do is plain basic, circuits in industry would be much more complicated. Not true.
- Everything starts simple and stays simple unless you really really have to improve upon it. Keep it stupid simple (KISS).
- Analog circuit design is not possible without insight:
- As a mm-Wave/RF IC designer, we rely lot on simulations. We lose insight and stop approaching things mathematically. DON’T DO THAT
- If you cannot meet specs, question the specs. System level solutions are more effective than heavily fine tuning a circuit.
- You work on your tiny block inside a module inside a chip. You are forever lost in optimization, debug and interface issues. There will be so many specs and corners to meet your performance that will keep your plate full. This is more true at senior to senior staff engineer level. You start taking more of a lead role after these levels.
- It’s important to learn how to use the simplest model for the job (instead of the most accurate one). Often times during design or debugging, you will be making models of things to understand. The writer itself used to make very accurate models and take pride in it, only to realize later that it had lost intuition or it has become too intimidating that no one will ever make an effort to understand it. Keep your models simple and intuitive.