Archive for the 'Analog synthesis' Category

If you are reading this, you may have had thoughts on blogging yourself, or perhaps you already are a blogger. One of the most valuable lessons that I have learned from writing a blog is how it can be be used for creating and publicizing my personal “brand”. Personal branding is a way to demonstrate the unique expertise and value that you can provide, to potential employers as well as to colleagues in your profession.

I was first introduced to the topic of personal branding in an article for which I was interviewed by EDN magazine; Life after layoffs: How to move forward after a job loss. Since then I have been asked to share my experience as a blogger with others, most recently at a career networking group hosted by Right Management here in Silicon Valley. My “Top 10 ways to attract subscribers to your blog” may be helpful to you in developing your own personal brand through blogging. You can view the slide show of my presentation here: Developing Your Personal Brand Through Blogging.

-Mike

Hello Everyone,

This blog just celebrated its 6-month anniversary on March-28th, so I thought it might be interesting to stop and take a look at a Top-10 list of the most-read articles so far.

Using “post views” as a measure of popularity (i.e. how often someone clicked on a given post’s URL), here is the ranking of most often-viewed articles since the inception of Analog Insights on Sept-28th, 2007:

1. More on analog synthesis and the non-cognescenti

2. Red Herrings: separating the truth from the hype in SPICE verification tools

In a 3-way tie:

3. … Because digital design is so easy!

4. A few random notes from ISSCC

5. How to subscribe to my blog

Followed by:

6. Design Verification. Analog… meet digital. Digital… meet analog.

7. AMS Verification at DVCon – Part II

8. Hierarchy and Isomorphism in Fast-SPICE simulators

9. AMS Verification at DVCon – part I

10. Reports of the Death of AMS SoCs are Greatly Exaggerated

Is there anything that we can glean from this? Here are my thoughts, but as always – let me know if you agree… disagree… all opinions are welcome.

The one thing that the top 2 articles have in common is that, in each of them, I attempted to debunk myths and dispel misinformation that is all too prevalent in hyped-up EDA marketing campaigns. I believe that you – my readers – will only come back here if you are getting information that is truthful and relevant to your work in analog design and verification. No hype here!

In analog synthesis and the non-cognescenti I addressed the misguided notion that analog design needs to become more like digital, by pointing out that the natures of analog and digital design are so fundamentally different that the tools required are different as well. It is unfortunate that there are so many industry voices still out there in the media and blogosphere that just don’t get that. As in the 2nd most article that I discuss below, this sort of thing distracts from the real issues we should be addressing. The cognoscenti… those of you who actually do analog design… you get it. Thanks for making that article #1!

In Red Herrings, the topic was FastSPICE simulation – where I addressed marketing campaigns that treat EDA tools like they belonged in a beer commercial… taste great/less-filling.. that sort of thing. That article has been up at the top of the most-viewed list from the day it posted, so that tells me that you all want the truth about how the tools we (EDA) provide can help you solve your problems, and not differentiation through labeling that is better left in the supermarket aisles.

How to subscribe to my blog quickly jumped up to the top 5. Thanks to my colleague Karen Bartleson who publishes The Standards Game, for linking to that article on her blog. I hope that you are checking out the other blogs on this site as well, and that the subscription techniques that I described are helping you to keep up to date.

It was good to meet many of you at the recent SNUG R&D night, and hear in person about the issues in AMS design and verification that are important to you. Here is one of the pics from SNUG (used with the kind permission of Ron Ploof – Synopsys’ New Media Evangelist, SNUG San Jose 2008). On the left is my colleague Godwin Maben, author of the Low Power blog.

Let me know any ideas you have that will make this more helpful to you.

-Mike
AMS Verification SNUG Analog design

Hi All,
I’ve written about this several times already (… Because digital design is so easy! and More on analog synthesis and the non-cognescenti), but it must make for some provocative headlines to perpetuate these “black magic” myths about analog design. With the ongoing demise of the print media, I suppose that I can’t blame them for stirring up some controversy. If you don’t get readers you don’t get advertisers. If you don’t get advertisers you are out of a job!

I was recently interviewed for another article on DACezine titled Automating Analog Design, Is it really a black art or just a red herring? - by Geoffrey James. It’s not a bad article, and Geoffrey even “borrowed” the title of one of my blog articles here: Red Herrings: separating the truth from the hype in SPICE verification tools. Imitation is a sincere form of flattery… right? And my “Red Herring” article has proven to be the most popular of all my posts here. As of the date of this post, it’s actually tied with the “non-cognoscenti” article for most viewed. I take that as a good indication of the type of articles you all are interested in reading. Thanks for checking them out.

But back to this “black magic” nonsense. As I have said before, I wish the editors and writers would get out a dictionary to see for themselves what a derogatory description of analog design that is. Black magic? Evil spirits? Demon worship? Voodoo?? I like to think that I have a pretty good sense of humor, but to all of us who struggled through multiple semesters of physics, circuit analysis and design, analog and digital signal processing theory, control systems, e-mag, etc… etc… that could be taken as an insult! Does anybody know where the Hogwarts Academy for Analog Design is?

Analog designers have to survive some of the most difficult course and lab work in all of electrical engineering, and then – once we graduate – we have to regularly endure often brutal design reviews by our peers. I’d love to participate in an editorial review that would mirror some of the reviews I had to deal with back in my design days. Now that would be fun! Why,  it was enough to drive me into marketing!

So (in the DACezine article) Gary Smith says, in regards to the so-called “problem” in automating analog design – that “the good news is the old farts are retiring and the new analog guys are willing to use tools.” Now, I’m not sure if I qualify as an old fart yet… but I am not planning on retiring any time soon, and you can be sure that I will continue to address the real issues in analog design and verification, and to speak up for all the hard work and talent that goes into making one an analog designer.

Now where the heck did I put my wizard’s cap?

- Mike
black magic analog design analog synthesis automation old farts

I received some good comments to my previous post (… Because digital design is so easy!) from Rich at Silicon Canvas, which I would like to follow up on. I get pretty passionate about this topic, and my reply to him was getting so long that I think it is better to place it here as a separate post.

Rich points out that overall analog design productivity has improved substantially due to advances in EDA tools, with schematic-driven layout as a prime example. I couldn’t agree more! Schematic-driven layout (SDL) is a great example of the productivity improvements brought about by analog EDA. I just wish I had SDL when I was designing my IC layouts by pushing polygons. (No.. I never actually had to cut rubylith!)

One key point I am trying to make though, is that EDA-enabled analog synthesis IS here, if you just understand that the process of implementing an analog design is fundamentally different than digital design. All the NC (Non-Cognoscenti) pundits don’t seem to get that.

The critics can only think of tools like Design Compiler. Digital synthesis maps RTL and gates to cells in a library. I could just as easily argue that digital synthesis is not REALLY synthesis, because someone had to design the cell library at the transistor level. Hmmm… designing the transistors… now that sounds familiar! I have yet to look at a chip photomicrograph and see a single line of RTL code… have you?

When I was architecting our synthesis methodology at Antrim, this was my starting point and our motto… do not compare analog synthesis to digital, because there is no Boolean algebra for analog. The philosophy I followed was to look at what analog designers do, find ways to make it more repeatable and reusable, while automating the most tedious tasks. Prior art at the time was mostly made up of academic attempts to create analog design compilers for Op-Amps… not particularly useful. Thinking of the solution without first asking what the problem is is not a recipe for success.

Analog EDA is the field of developing tools to increase analog designer productivity. Thinking of synthesis in terms of compilation does not equal finished silicon, for analog or digital designs. Ultimately it’s all about the transistors, and the flows to get there for analog and digital designs are necessarily different.

-Mike
analog synthesis design compiler non-cognoscenti

If that popular game show ever has a category called EDA MYTHS, I expect this to be right up there for the Double Jeopardy round.

(Although, based on my experience in a failed startup… maybe Final Jeopardy?)

Remember, you must pose your answer in the form of a question…

Contestant> “I’ll take EDA MYTHS for $1000, Alex.”

Alex> For $1000, the answer is … Because digital design is so easy!

Contestant> “Why is analog design so hard?”

Alex> You are CORRECT!

I don’t know why, but for some reason over the past several months there seems to be a fixation in the EDA press on questions like “Why is analog design so difficult?”, or “Why is analog design black magic?” which I already commented on in one of my earlier blog posts back in October. You don’t see analog designers asking these questions, so why is this type of question so popular with the analog non-cognoscenti?

Mike’s DEFINITION:

Analog non-cognoscenti: One who has never actually done an analog design and has no expert knowledge of the subject.

These questions are typically being posed to EDA industry marketers, who are also typically not experienced in analog design, to defend why “analog tools aren’t successful’” as Ed Sperling claimed in his recent DACezine article.

The problem, as I see it, is confusion caused by how easy digital design is. With digital synthesis you can create a working chip with no circuit knowledge; all you have to do is write some code. Why isn’t analog design this way? What’s wrong with all you EDA companies?

Or, since there have been several noteworthy failures of Analog Synthesis startups (mine was Antrim)… “Are Analog Designers Secret Luddites?; the question that Geoffrey James poses in his DACezine article?

I was interviewed for that last article, but was told that the topic was going to be “Way too Small: Will SoC and Mixed Signal be Incompatible?”
(My previous post here “Reports of the Death of AMS SoCs are Greatly Exaggerated”, puts the 1^st question to bed because you can find numerous examples of 90nm, 65nm, and even 45nm AMS SoCs being presented at the upcoming ISSCC in San Francisco.)

Obviously, that’s a very different issue than the author’s allegation that it’s a “fact that EDA vendors have so far lagged in helping analog designers”.
(I addressed that accusation in my blog on Analog design is NOT black magic… but it is VERY hard as well).

But back to the analog synthesis question… what is synthesis anyway? Well, m-w.com says that synthesis is “the composition or combination of parts or elements so as to form a whole”. So let’s not forget that somewhere, someone created a circuit for all those logic gates that populate a cell library in the digital synthesis flow. And the truth is that digital design hasn’t required circuit design expertise for a long… long time, going back to at least 7400 TTL logic days and probably even earlier. Some circuit designer built those chips too, so that the digital designers could “synthesize” their PCB.

I think that the problem with all the NC (non-cognoscenti) thinking is this:

There is no Boolean Algebra for Analog!

Digital design is by definition easier than analog design, now there is a FACT. You can perform digital design with Boolean logic, simple rules and tables like Karnaugh maps. I’m sorry, but analog design does not work that way and it never will!

However, there is in fact an analog synthesis process that is performed in hundreds of companies every day, and guess what… it’s enabled by some very powerful EDA tools. The EDA industry has not “lagged in helping analog designers”. That’s just nonsense!

The EDA industry has facilitated orders of magnitude increases in analog designer productivity. If that wasn’t true there would be no consumer electronics industry today. Nobody could afford the time it would have taken twenty years ago to design the mixed-signal devices at the heart of today’s cell-phones and iPods.

I think it was very interesting to read, in Ed Sperling’s DACezine article, that “the biggest problem (at National Semiconductor) is simulation”. When I first started doing analog design, my synthesis process lacked the ability to simulate complete circuits like PLLs, and ADCs. Today’s SPICE and Fast-SPICE tools can handle these types of circuits routinely, and in a small fraction of the time it would have taken back then. Simulate a circuit with tens of thousands of transistors? (or maybe more)… you’d have to be nuts to try that twenty years ago. But, just as Design Compiler is now inextricably a key to the digital synthesis process, SPICE and Fast-SPICE is at the very core of the analog synthesis process.

And designs get bigger and faster, and more issues come with each new generation of nanometer processes. So we must constantly make our simulators go faster while analyzing more complicated device models efficiently, increasing capacity for more parasitics and layout effects, in order to keep up with designer’s requirements. It’s the same for digital as it is for analog. Bigger. Faster. (Dare I say cheaper.. ouch!).

So my final word (today) to the NC folks is that EDA has facilitated analog synthesis. It’s just not the same as digital synthesis. It shouldn’t be, and it never will be.

Let’s focus on the real problems, rather than propose solutions in search of problems. The EDA industry hasn’t failed to help analog designers. Custom analog design is not a “plague”. Analog designers are doing amazing things, and analog EDA tools are a key part of that.

I hope to see many of you at ISSCC to hear about all the latest mind-boggling transistor-level innovations, from the minds of the analog cognoscenti!

-Mike

analog design digital design black magic non-cognescenti boolean algebra ISSCC synthesis Karnaugh maps