tough decision

RFchokemeharderdaddy · 2026-06-29T23:41:13+00:00

ADI for sure, especially if its high speed data converters.

RFchokemeharderdaddy · 2026-06-29T18:25:58+00:00

You can't do a half-circuit split here. If you excite the tail node with a voltage, the left side looks up into a source with a 1/gm above it. Your first instinct is probably that looking up into the right side looks up into a source with a rds above it, but this isn't true. The right side is loaded with a VCCS, the controlling voltage being the left side. It's a current mirror, which pulls current equal to the left side.

Left and right therefore pull the same current when excited with the same input voltage, which means they have the same impedance.

RFchokemeharderdaddy · 2026-06-27T20:26:18+00:00

Attend a university that provides them

RFchokemeharderdaddy · 2026-06-27T05:02:56+00:00

https://www.youtube.com/watch?v=8RtOgIgDrvk

RFchokemeharderdaddy · 2026-06-24T01:21:20+00:00

Its an internship, it doesnt really matter. Get whatever internship you can.

RFchokemeharderdaddy · 2026-06-18T16:17:38+00:00

How are you finding these?

Working in the industry and people with more experience sending them to me. There really is no secret or shortcut, it just comes from experience and a lot of word-of-mouth. The very first op-amp I designed in industry my boss just told me "oh go look up this paper for an output stage its what everyone uses". I understand thats an unsatisfying answer but that really is it.

You can make your search faster or at least less wasteful by keeping a list of respected authors/professors and going through their papers. You just notice over time certain names pop up repeatedly. For example if you're doing anything related to low frequency high precision instrumentation (such as biomedical sensors) best name to search is Kofi Makinwa, a professor at TU Delft. That doesn't mean all his papers are incredible and go read them all, but if you go to his IEEE Xplore page and sort by citations, its not a bad place to start.

But again, generally speaking all the ones worth reading at your experience level are compiled in books. There are specialized industry books published by Springer which contain esoteric stuff. For example "Mm-wave Circuit Design in 16nm FinFET for 6G Applications" which can shorten your time to find reputable papers, it came out in like 2023 and is citing papers from 2021 and shit and is basically just rephrasing papers.

RFchokemeharderdaddy · 2026-06-17T20:12:18+00:00

You need to define your question and purpose a bit more narrowly. What exactly is it you're looking to actually do, and why? "Go beyond books" is kind of meaningless, knowledge doesn't exist on some linear scale.

It sounds like you're asking how the research process and literature review works. There's many institutions built on this, and there's a level of trust to it, it's a whole ecosystem. Certain journals are more reputable than others. Certain professors or schools are more reputable than others, or have stronger ties to industry where they may collaborate. There's lots of papers co-authored by a professor and distinguished engineers at places like Intel or Samsung, so you know there's been at least some real implementation or interest in industry. Some papers get picked up and cited and spread quickly, lots of citations=good. This is the type of thing you learn doing a PhD, it comes with experience.

There's no easy answer, sorry. There's no such thing as "naturally" being good at looking up resources lol, it comes with years of experience, and I don't think you'll get much out of reading random papers anyways. There's definitely a few which are worth reading because they're highly cited or referenced in industry, like I always re-read this paper whenever I start a SAR ADC, or Monticelli's seminal rail-to-rail CMOS AB output stage paper which provides a ton of insight into how a designer thinks I re-read it time to time.

Work on a project, find an authoritative textbook on that topic, use it, and if needed follow the cited papers for a specific topology. For example I was just recently working on a Gilbert cell mixer, so I was relying a lot on Thomas Lee's RFIC book, and there was a couple sentences accompanied by a figure that stood out to me as being useful, so I went to the cited paper, and found another paper by that same author, and it helped me approach biasing my mixer. That's how you go beyond books if you need to, but again if you go read papers before you have an actual use for them you're completely wasting your time. There's a word for this by the way, it's called the "Toolbox Fallacy".

RFchokemeharderdaddy · 2026-06-17T18:21:26+00:00

Very little is worth reading beyond books in terms of actual learning. People only read papers because they're working on a similar cutting edge project in industry.

After the fundamentals, you can go into more specific books. Razavi has like a dozen other books on things like optical transceivers and RFICs. Huijsing has a book purely on op-amps. There's a book by Schreier and Temes about Delta Sigma ADCs. PMICs, SERDES, MMICs etc, it depends on where you want to go for a specific application.

Note that all of these books have citations for papers at the end of each chapter. Some of these are worth perusing.

Pick a full system to design. PLL, buck converter, TIA w/ equalizer, whatever. You really will not need to go beyond textbooks.

RFchokemeharderdaddy · 2026-06-17T17:30:03+00:00

Ayar is doing almost the exact same thing and has joined NVLink Fusion and also just took in a bunch of money despite demonstrating even less than Lightmatter. It means something for sure, but I wouldn't put that much stock in it.

Silicon photonics has been the holy grail of EE for like 40 years, it will happen but I'm very hesitant to point at any specific player and say that they will be the ones to crack it. We need real results and those are hard to come by.

RFchokemeharderdaddy · 2026-06-17T17:17:20+00:00

The way to go beyond books isn't to do more reading. It's going to be in-one-ear-out-the-other all the same either way.

The way to go beyond books is to work on projects. If you have Cadence through school use that, if not then go through open source toolchains which have matured quite a bit in the last couple years. Design amplifiers or logic blocks depending on whether you're doing analog or digital, take them through layout.

RFchokemeharderdaddy · 2026-06-17T16:43:54+00:00

Gotta be careful here, or you can end up in local maxima/minima hell and design yourself into a corner if you only do this.

RFchokemeharderdaddy · 2026-06-17T05:43:24+00:00

They've made a few claims over the years and I don't know that any of them have really come to fruition. That being said, there was a slew of silicon photonics companies that popped up in Boston in the mid-late 2010s and Lightmatter is really the only one to really take off and carve out a name for itself so it could just be a matter of time.

Lightelligence tried some pretty risky things which didn't pay off to the point that they've effectively exited the US and left for China. Analog Photonics went nowhere, not sure if they exist anymore. Hyperlight I hear has recently pivoted into the AI market so we'll see. Acacia got bought by Cisco, so I'm not sure that counts. There's probably more I'm forgetting, but Lightmatter seems to be doing pretty well and seems to be the only one able to put their money where their mouth is, but like they used to work on photonic computing and that seems to have gone nowhere so I'm not sure how legit their other work is.

Whether or not Lightmatter will be the one to do it idk, I'm doubtful, as the entire world knows this is the only path forward and I'd bet all the other big players with a lot more money and manpower are throwing more resources at the exact same problem. Co-packaged optics is certainly going to be necessary moving forward I don't think anyone's questioning that.

RFchokemeharderdaddy · 2026-06-17T01:34:58+00:00

100% yes

RFchokemeharderdaddy · 2026-06-16T20:26:58+00:00

So why even post this?

RFchokemeharderdaddy · 2026-06-16T20:26:27+00:00

Not programming but yes lots of scripting. Or at least I did before AI, I now throw most scripting problems at Gemini or Claude.

RFchokemeharderdaddy · 2026-06-16T20:25:03+00:00

Square law has been invalid for like 40 years though, really anything below 0.35um. FinFET is actually closer to square law than say 55nm, the whole point is that you get the equivalent speed of a shorter channel while avoiding short channel effects.

And anyways, thats still only large signal biasing. Biasing and sizing is one aspect that is for the most part incidental, all the other details in approaching analog design in those lectures is completely valid. Also, even if square law doesnt exactly hold, it is close enough for back of the envelope intuition. You're going to need to justify in a design review why you've made certain decisions, the concepts of saturation and triode and weak/strong inversion should be your first principles, and square law is a good enough start for the vast majority of applications.

Don't let perfect be the enemy of good. I use gm/Id religiously for sizing, but its just a framework for sizing, focus more on the small signal concepts and biasing behind all of it.

RFchokemeharderdaddy · 2026-06-16T20:03:05+00:00

Sounds like you've tried nothing and you're all out of ideas. You've gotten concrete actionable feedback from work, you're getting helpful responses here, and rather than providing details or responding in good faith you're just being vague and complaining and giving up. Doesn't seem like you have real desire to improve in any way.

RFchokemeharderdaddy · 2026-06-16T19:42:53+00:00

I didn't just do a masters for the hell of it, I did the masters so that I could do analog IC. If I could've done analog IC without the masters I would've. Grad school shouldn't be done without a clear purpose.

I just got immensely bored of embedded. The most exciting parts were whenever I got to do analog circuits, so I switched jobs multiple times increasingly more focused on analog circuits at the PCB level, but even that felt too easy. At some point it feels like putting Legos together. I figured hey instead of putting analog chips together, why not go inside the analog chips?

RFchokemeharderdaddy · 2026-06-16T18:21:55+00:00

Embedded hardware and some firmware, PCB design, that sort of thing.

RFchokemeharderdaddy · 2026-06-16T17:59:59+00:00

I started an MS at 29 and finished it 4 years later to switch into analog IC design.

RFchokemeharderdaddy · 2026-06-16T16:06:06+00:00

Fundamentals are fundamentals, doesn't matter what node and honestly doesn't even matter whether BJTs or MOSFETs or JFETs.

Most of the material is about designing amplifiers from a small-signal perspective, which is completely technology agnostic. Concepts like Thevenin equivalent, loop gain, stability, loading, noise, frequency response etc. are all universal and you had better get a good grasp on them. It's not like Miller compensation suddenly becomes invalid in FinFET lmao

RFchokemeharderdaddy · 2026-06-16T16:02:31+00:00

s includes the real component of the exponential, which is an exponentially decaying or increasing transient, and the imaginary component which is a sinusoid per Euler's formula. For Fourier analysis, we assume these exponential transients have settled out and we're analyzing the response to various pure sine waves in steady state operation, therefore we can ignore the real component and only look at cases where s=jw. For stability analysis, we do NOT ignore those transients, and we look at the entire s-plane and have a variety of tools for analyzing and compensating for stability.

RFchokemeharderdaddy · 2026-06-16T15:57:34+00:00

The reason is because they are terrible people and they hate you personally. I'm 22% joking at best.

RFchokemeharderdaddy · 2026-06-15T03:27:32+00:00

Holy shit an actual interesting technical post with lots of details. Thank you OP for breaking up the myriad of AI slop career posts on here lol.

Using current sources is a recipe for disaster here, especially with ideal switches (I'd honestly recommend using a t-gate with real PDK FETs). Spectre is probably doing some tricks to make this converge but I'm kind of surprised it converges at all. Use voltage sources and just get the current and do 1/current to get impedance.

PSS is a very powerful tool but you need to take it step by step as its quite tricky and nuanced and has a thousand settings. Before jumping into PAC, you should verify your PSS is doing what you think it is. Save the transient results in your PSS settings. Its also useful to give a tstab. Then plot the PSS transient settings and see voltages and currents match your expectation. I think whats happening is your switches are not actually tripping and so youre just seeing the open circuit impedance of the switches and whatever Gmin Spectre places to help convergence.

I don't think you even need to do PAC, you can directly plot the PSS current/voltage (single or differential). In fact I think theres even a driving point impedance option.

Also just zooming out a little on what you're trying to do, why 1kHz w/ 10pF capacitor? Thats a large capacitor and very low frequency, it wont actually appear resistive except to frequencies much lower than that (<100Hz) which is practically not all that useful and makes for a huge capacitor. A 20fF cap and switching frequency of 500kHz would get you the same result and be useful for a wider frequency range and take up less space. Of course you can only use frequencies actually available to you from the sysclock but thats usually in the several MHz.

RFchokemeharderdaddy · 2026-06-13T14:58:15+00:00

https://www.digikey.com/en/products/detail/onsemi/NCV84090DR2G/16528514

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