The Dean speaks

The Dean speaks
It is not true that Bob Pease chased me down the hall screaming, "Why use Spice if it's going to lie to you?" though the misuse of Spice IS one of his hot buttons. What he DID do was correct a misconception I had about him from his student days at MIT. He was a mountain-climbing buff, a colleague of mine (and classmate of Pease's) told me. One day Pease entered a second-story classroom through the window. "Not true!" Bob insisted. "It was a fourth-story classroom."

I'm not sure if Bob wants to duplicate that feat these days, but if we can talk about classrooms for a second, I would point out that he has certainly spent a good deal of his engineering career in front of a blackboard. It's more than the keynote he gave at last year's DesignCon; it's more than the NetSeminars he has broadcast on the Internet. His zeitgeist, his intent, is probably closer in spirit to the "Pease-o-grams" he has distributed to many of us throughout the years. I believe he is concerned - deep down, concerned - that his fellow engineers "get it right" when it comes to the design of analog circuits.

It turns out, Bob Pease is now the Dean of National Semiconductors' "Analog University" (http://www.national.com/analogu/index1.html), a web-based learning tool, formally announced March 31st. Complete with carefully structured lesson plans, reading and research assignments, and exams - along with a "faculty" made up of National's best-known application gurus, the "University" intends to be a resource for engineers who need to refresh or upgrade their knowledge of analog techniques and part types. They can take courses with National's experts online, and earn digital "Diplomas."

The broad subject areas at Analog University include power management (including heat dissipation and thermal management), amplifiers, low-voltage differential signaling (LVDS), data conversion, audio, and display interfaces. The University features frequent Planet Analog contributors like LVDS guru John Goldie and JTAG maven Brian Stearns - as well as Mr. Bob himself.

There's a mixed blessing attached to getting these lesson plans from National Semiconductor (as opposed to a non-commercial source like CalPoly or UCBerkeley, or a lower-to-the-ground-but-ostensibly-neutral seminar like those once conducted at the Analog & Mixed-Signal applications conference). In the hands of National's applications folks, I would suggest, you get some pretty solid tutorial information. But the circuit design examples (surprise! surprise!) utilize National's own parts. On the plus-side, you can see exactly how these often-generic parts (and the circuits that use them) actually behave by running them through the embedded "Webench" simulator. (It's like doing your course "lab work" online.) On the minus-side, if there are some circuit variations or different component values you need to observe in using similar part types from a competitor, you may not hear that from National.

On a lot of levels, the "Analog University" is not very different from the touring/teaching seminars sponsored by National or by competitors like Texas Instruments or Analog Devices. TI, for instance, conducts an exhaustive series of seminars around the world on analog subjects. A currently-touring seminar series on power supply design features gurus like Bob Mammano (analog hippies may remember him from Unitrode and Power General before that), who is arguably the inventor the pulse-width modulator (PWM) approach to switching power supply design.

The day-long seminar (www.ti.com/rd/powersem02) costs $95, and features topics like "Understanding and Optimizing Electromagnetic Compatibility in Switchmode Power Supplies," "Designing High Power Factor Off-Line Power Supplies," "Achieving High Efficiency with a Multi-Output CCM Flyback Supply using Self-Driven Synchronous Rectification," "Transformer and Inductor Design for Optimum Circuit Performance," "Under the Hood of Low Voltage DC/DC Converters," "Paralleling Power - Choosing and Applying the Best Technique for Load Sharing," and, inevitably, "An Introduction to TIs Newest Power Supply Components."

Apart from TI's "Knowledgebase" for Analog and Mixed-Signal Products (go to "analog knowledgebase" at www.ti.com/corp/technical_support.htm), it's not clear to me how the notes from these seminars might transition from paper handouts to web-accessible files. The information here would be extremely valuable to power supply designers - even those using generic part types. (Somebody should note: I wouldn't mind featuring some of this on PlanetAnalog.com.) But, in fairness to those engineers who spend $95 and make an effort to travel to the seminar site, the material available online and for free might not have the same depth as the material offered at the in-person seminar.

Analog Devices also sponsors seminar tours: I've been saving the dog-eared notes from one of ADI's Mixed-Signal Technology Seminars as my reference text on data conversion architectures. A current ADI seminar series on "Op Amp Applications," I'm told, features designer Walt Jung and the book version of his seminar notes is selling briskly. The book is effectively an updated version of his popular "IC Op Amp Cookbook," reflecting the changes in op amp technology we've come to know and love (e.g., higher bandwidth, tighter offsets, battery and single-supply operation). Ordinarily, the complete set of ADI's seminar notes are available for sale while the tour is under way, and then selected sections are posted to the web in pdf format when the seminar concludes. Here, because of the reputation of the author, there is a very high demand for Walt Jung's seminar notes. (Look at www.analog.com/seminar to order the new Op Amp book).

The main advantage of the Analog University is that it puts a great deal of tutorial material on analog design in one accessible place. "What National has done is put a box around it and given it a name," a competitor says, hard pressed to deny that novice analog designers will find it useful.

Both National's Analog University and TI's Analog Knowledgebase have a searchable database - frequently asked questions (FAQs) - that can be assessed with a Natural Language Interface. A query about LDOs, for example, would bring up a list of concerns associated with "low-dropout regulators." I don't want to dispute whether TI or National does a better job with "natural language" queries. Both seem to pull up a great deal of information in response to a typed query.

But National's program will respond (albeit in English) to queries typed in a foreign language. It's basically a shotgun response - the most likely answers - to a keyword query, Pease demonstrated. "What the hell is an LDO?" he typed. The system chugged for a few seconds, and then came back with roughly 180 entries under "low-dropout regulators."

There is a danger with a natural language emulator, one of National's press agents jested, in that it can take you at your word. You ask the machinery: "What the hell is an LDO?" and it responds, "Hell: a hot and crowded space..."

I wouldn't want to speculate how much voltage and current it takes to run Hell, but (who knows) maybe that'll be a seminar topic someday too.