1st Qtr 2011
(c) 2011 Design/Analysis Consultants, Inc.
Newsletter content may be copied in whole or part if attribution
to DACI and any referenced source is prominently displayed with the copied material
This Issue: NEWS BITE: Astronomer Discovers Giant Eye Staring At Earth! / DESIGN MASTER: New Pricing Structure / COMPONENTS: The Most Popular Op Amps? It’s A Secret! / CONCEPTUAL DESIGN: Look At The Big Picture / COOKING & MEASUREMENTS: Why Engineers Get It Right
NEWS BITE: Astronomer Discovers Giant Eye Staring At Earth!
The Helix Nebula, “Hubble’s Best Photos” by Lauren Effron, Discovery News
DESIGN MASTER™: New Introductory Pricing Structure
Effective for 2011, we’re changing our introductory price structure for DM to a flat fee of $85/copy, single user ($25 for upgrades), and providing modeling packages in DMX template format at an added charge. DMX is a DM feature that allows expertly-designed “fill in the blanks” templates to be used for thorough and efficient worst case analysis. Click here for details.
With the introductory pricing structure, DM will only be supported via email, and only with regard to DM operation, not circuit or part modeling. For those who may need help with modeling, please see DM V8’s expanded help content, and refer to the available DMX templates. If more extensive assistance is required, please contact us with regard to a DM training seminar, or for the provision of custom circuit or part models.
Offer expires 30 April 2011.
We were looking for some guidance in building up op amp models for our DMX templates, so we asked several major semiconductor vendors this question: “What are your most popular op amps?” Surprisingly, although the technical contacts said they would like to provide the data, they couldn’t; their sales departments considered the data proprietary, due to competition concerns.
Therefore it seems our alternative is to create our own “favorite” lists. If you have some preferred op amp (or other analog IC) part numbers that you would like to share with the DM design community, please send them in. We’ll post them in future issues of this newsletter. The data will also provide guidance for our development of part models.
In the 12 December 2010 issue of Electronic Design, Louis E. Frenzel discusses some modern versions of the ubiquitous 555 timer IC (“And You Thought The 555 Timer Was Dead?“).
In that article, Mr. Frenzel also refers back to an earlier article of his , in which he asks, in essence: why in the world does the 555 timer still exist? (“The 555: Best IC Ever Or Obsolete Anachronism?“, 12 Dec 2007, Electronic Design).
Might we suggest an answer? The 555 provides a simple common function in an elegant low-cost manner. This does not mean it is always the best solution (Mr. Frenzel mentions some alternatives), but it certainly is an attractive option, particularly for circuits that don’t contain a uP.
I suspect that Mr. Frenzel was deliberately being provocative to stimulate conversation, particularly with his implication that all modern products contain a uP. If that were true, then yes, why add a part when the uP can provide the timing capability for free? But a huge number of products do not contain uPs, because they simply don’t need uPs. In fact, avoiding a uP has additional advantages in addition to cost avoidance, including better reliability (by keeping things simple), and by eliminating radiated emissions noise. We have saved some of our customers a lot of money by showing how a dirt-cheap non-uP circuit can achieve the functions they need, while also avoiding the noise issues that would require EMC compliance certification.
Mr. Frenzel quotes from a 1997 article, “…the 555 is dated mainly because it is no longer compatible with the mostly low-voltage (less than 5 V) circuits in use today. Furthermore, it consumes excessive power compared to today’s circuits.” But this ignores the fact that the 555 has been continuously reincarnated over the years with better performance, operating at lower voltages and current, and available in various modern packages.
From a broader perspective, we think it’s important to stand back and look at the big picture during the concept design phase. We shouldn’t just indulge our prejudices, and grab the parts and designs we’re familiar with. Rather, we should ask: what’s the optimum design? Among other considerations, this means we need to challenge our assumption that newer means better. Maybe, maybe not. There are lots of situations where older-technology designs are much better for certain applications — all things considered — than their modern counterparts. A few examples:
- 4000 series CMOS: these senior ICs are great solutions for low cost, low speed, noisy industrial applications.
- Mechanical relays: ancient, but like the 555, continuously modernized, and still the best solutions for numerous higher power industrial designs.
- Older IC technologies in general: lower cost, less EMC issues, and less susceptibility to electromigration, which is becoming a significant concern with modern minimal-geometry ICs.
COOKING & MEASUREMENTS: Why Engineers Get It Right
“Cooking is awesome because it’s applied science. Biology, chemistry, physics, they all come into play when you’re cooking. I don’t know that I necessarily do anything specialized. I know that some of my more particular habits come out when I’m cooking. I very rarely cook meat, for instance, without a thermometer. I know there are these old-school cooks who would turn their noses up at me because they can tell by giving their roast a touch or by poking it in the right spot and seeing what color the juices are, they can tell when it’s ready to come out of the oven. Well, I can tell when it’s ready to come out of the oven when it’s the right temperature and that is okay with me. You know, my bread—before I invested in a thermometer, sometimes it was too dry and sometimes it was gummy in the middle, but now it’s right every time. I use a kitchen scale for almost everything. If you think about a cup of flour: If I measure the cup of flour it may weigh 4 ounces; if you measure your cup of flour, it may weigh 5 ounces, because the flour is compressible. So you achieve a degree of precision when you measure things that way. Nothing drives me crazier than when you look at a recipe and they call for 1 large onion. I’m guessing that one large onion in Texas is massively different that one large onion in southeast Missouri. You know I can get an onion from the store here that weighs almost a pound. I have no idea if that’s what they meant. So my life got substantially more precise when I was able to start making notes, you know—this much onion worked, this much onion didn’t.”
–April Woods, as quoted in “Geeks Cooking: April Woods, the Hungry Engineer,” an interview by Susan Hassler in IEEE Spectrum
Posted on February 1, 2011, in Concept Design, Design Master, Design Master Expert Assistant, Electronic Components, Electronics Part Models, Measurements, Op Amps and tagged 4000 CMOS, 555 Timer, Concept Design, Cooking, Engineering Thinking, Op Amps, Relays. Bookmark the permalink. Leave a comment.