Monthly Archives: June 2007

IC Friday: Dallas Semiconductor’s MAX2323E

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Today’s chip is a multi-mode CDMA low-noise amplifier/mixer (not a RS-232 tranciever as the name suggests). The source of the chip is a Motorola V60 handset. It is somewhat interesting that the chip has both round and square coils on the surface, if any IC designers are reading this and know the rationale behind it, please leave a comment.

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( max2323-max2325.pdf )

Orcad Layout has reached end-of-life

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It is now official:

 

To our valued OrCAD Layout customers:

As demonstrated in the OrCAD® product 16.0 release, Cadence® continues to invest in providing a fully scalable PCB design solution for our customers – one that grows with you as your PCB designs grow in complexity. We’ve all seen the PCB design landscape change dramatically in recent years. In order to help customers meet current market demands and maximize productivity, Cadence continues to leverage the power of its proven Allegro® PCB technology within our OrCAD product line. This allows Cadence to offer customers unique suites and technology bundles that address current and future design challenges.

This letter is intended to communicate some important developments regarding the future of Cadence OrCAD Layout. Cadence has begun the End-of-Life process for Cadence OrCAD Layout technology based products.

Please Note: Cadence OrCAD Capture, OrCAD Capture CIS, and PSpice® technology are all integral parts of Cadence’s long-term product strategy and are not affected by this notice.

Effective July 31, 2007, Cadence will no longer sell the following Cadence OrCAD Layout based technology products:

1. OrCAD Layout (PO1410)
2. OrCAD Layout Plus (PO1420)
3. OrCAD Unison PCB (PO1510)
4. OrCAD Unison Ultra (PO1530)
5. Layout Studio (PS1430)

We acknowledge that transitioning software systems is never easy and is often a juggling act between investing in learning new technologies and meeting current business priorities. EMA is committed to ensuring we do everything possible to help minimize the impact on you, wherever possible. To help ease the transition, Cadence is providing OrCAD Layout customers with multiple paths for migrating to new technology that leverages the power of Allegro PCB Editor. Learn more about the various transition path options by visiting http://www.ema-eda.com/orcadlayout.

The products entering End of Sale will be supported thru March 31, 2009. After that date, these products will no longer be supported for hot-fixes or support calls and will not be shipped on the OrCAD CD set.

If you have any questions, or would like to discuss these changes and how it may impact you, please contact your EMA Account Manager. You may also contact the EMA technical support team at 585-334-6001, Option 5, or by email at techsupport@ema-eda.com.

We remain focused on providing solutions to ensure your ongoing and future success!

Best regards,
Manny Marcano

President and CEO
EMA Design Automation

Many people saw this coming as virtually no new features have been added to Layout in the past four years, only bug fixes. Although Allegro PCB Editor is a little bit more pricey, I think its worth it, especially for high performance designs. Finally, the Layout site gives some instructions on migrating. Layout,… we have had some great times together:

  • The great and unavoidable crashes that used to occur when the user would lock the (win32) workstation running Layout
  • All the excellent times that Layout would close your design without saving if you hit CTRL-C twice instead of once
  • Layout’s inability to recognize artwork that was placed on the Global Layer (0) when creating Gerber files

How to write and present in the life sciences

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It became apparent that the National Institutes of Health have a virtual carreer center that some decent guides to presenting and publishing. Although a lot of the information there geared to publishing in scholarly journals, the lessons can be taken and applied to many fields of technical writing. Furthermore, if you are a U.S.A. resident, this is your tax money at work, so you might as well reap the benefits.

App note on using op-amps as comparators

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I am working on re-designing my isolated stimulator to work with current output instead of voltage output as it does at present. One of the associated problems is designing the output stage so that the potential between the two stimulating electrodes does not exceed a pre-set value governed by various safety and electrochemical limits. Without going into too much technical details, comparators are involved to create circuitry that will clamp the output voltage, even if it does not reach the prescribed current, at safe limits.

In the past, I have heard various views on using operational amplifiers as comparators. The general consensus is to avoid using them in that manner, however, some applications exist where cautious use can be accomplished without too much performance sacrifice. The AN-849 note, by James Bryant from Analog Devices Inc., gives a short overview of the pros and cons of this use and gives light to some subtleties that are not fully apparent.  One such issue that I did not think of from the start was including small amounts of positive feedback to increase stability.

P.S. Be sure to check “how to make sense of a data sheet“, also from Analog. The document is both informative and entertaining.

( an-849.pdf )

Linear and switching voltage regulator fundamentals from National Semi.

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I recently found this guide from National Semiconductor going over the basics of various voltage regulator designs. They go over the basics as well as some high level schematics of these designs and a couple of application notes. I skimmed over it and found it to be a decent read, I may still disagree with their points regarding the utility equivalent series resistance in shunt capacitors so I will try to post on that topic when I find more substantial information.

( voltage-regulators.pdf )

How to disable icons in the block diagram view in LabView 8.2.1

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One of my annoyances with the default settings in LabView is that it places all terminals on the front panel as icons in the block diagram view. These icons are large and tend to push stuff around when they are created automatically. Every time I have to re-install LabView, I figure out how to disable this feature only to promptly forget it. This time around I will record the simple fix to save myself time in the future. The setting can be disabled by going into the Tools -> Options screen in either the front panel or block diagram. Block Diagram is then to be selected from the left side and Place front panel terminals as icons must be unchecked from the right side. Now your block diagram is safe from bulky icons, until the next LabView upgrade that is.

IC Friday: TI’s INA116

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The chip here is the INA116 from TI (Burr Brown). This is an excellent instrumentation amplifier and a true workhorse here in the lab.  It is apparent from the layout that this is a BiCMOS and it should be noted how large the die is compared to other integrated circuits. There also many more resistors on this die than some of the other analog circuits with signs of laser trimming.

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Free lectures on mathematics from Dr. Lawrence C. Evans

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I am participating in a summer reading course on stochastic differential equations and subsequently ran across lecture notes from Dr. Evans entitled “An introduction to stochastic differential equations“.  They give a quick introduction to statistics and Brownian motion followed by stochastic integrals including the Ito formula. Finally stochastic differential equations are introduced and their applications are given. I have only looked over the first half of this in detail and found it to be pretty reasonable. Furthermore, Dr. Evans has a larger set of available publications which include lecture notes and surveys. The semi-official book for the course is “Elementary Stochastic Caculus with Finance in View” by Mikosch (typo is reproduced from inside the front cover). A review of the book will follow later when I read more of it.

Why pasta? It reminds me of a stochastic sample set. Image was found on Musable Gourmet.

( lawrence_evans_sdes.pdf )