[Engineering Feature] PACs Become Task Masters
As global pressures squeeze manufacturers, many feel the urgency to optimize equipment in their plants. Existing controls are being tossed out and replaced with modern programmable automation controllers (PACs) that deliver more processing capabilities and more network connectivity. PACs have been gaining acceptance for years, giving engineers a single platform to address a broad range of needs. These platforms include software, which eradicates the ...
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Terry Costlow
[Technology Report] Ultracapacitors Branch Out Into Wider Markets
Once the staple of brute-force power supplies and large industrial and consumer power applications, ultracapacitors are now finding their way into products of all sizes, particularly portables. Also called supercapacitors, these components are notable for capacitance values ranging into the thousands of Farads and fast charge/discharge rates. With the ability to store massive amounts of energy for long periods of time, ultracapacitors behave more like a battery ...
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Mat Dirjish
[Leapfrog: First Look] Stack Monitor Chips Without Isolation Concerns To Give Your Electric Car Some Zip
Okay, you want to design an electric car. Whatever kind of motor you decide on, you’re going to want to run it at a pretty high voltage. That means stacking many batteries in series to get to that voltage, which introduces interesting challenges in monitoring and charging circuits as potentials at the negative electrodes rise above system ground. This is not a new problem. But as long as it’s been confined to products like golf carts and nuclear submarines, ...
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Don Tuite
[Design View / Design Solution] Get Started On Your LXI-Compliant Instrument Design
The LXI Standard is an exciting communications protocol development for the testand- measurement industry. Unfortunately, members of the Consortium have been the primary writers associated with the information published regarding the LXI Standard. Since, having participated in its development, they also possess an intimate knowledge of the standard, they have also been able to quickly develop products that leverage off this technology. Thus, it...
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Paul Franklin
[Ideas For Design] Using Copper Traces As Ballast Resistors Ensures Balance
The data sheet for the LT3080 linear voltage regulator suggests using printed-circuit-board (PCB) traces for ballast resistors. Although the LT3080’s low offset voltage suits it well for this technique, it can be used for other ballast applications— for instance, for a set of bipolar transistors. For example, in the figure, ballast resistors R1 and R2 can be short lengths of copper trace. In a practical case,...
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Tom Bruhns
[Ideas For Design] Superior JFET Biasing Improves Amplifier Performance
An N-channel JFET has a low bias current when its gate is biased negative to the source. However, this requires either that the gate voltage be biased negative with respect to the source voltage or that source voltage be biased positive with respect to the gate voltage. For ac amplifier designs, gate biasing can be made self-biased by using an RC network at the source to hold the positive voltage for a period longer than the time period of the input pulse/frequency...
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Shyam Sunder Tiwari
[Ideas For Design] Rotating LED Array Emulates Marquee-Type Display
I use this display circuit to expose students to the concepts and characteristics of scanning displays. Basically, a message is delivered to the CPU (a Microchip PIC16F76) over an RS-232 interface. The message is displayed on a vertical array of eight LEDs, which are spun by a dc motor. As they spin and take on new positions, the LEDs are updated with new lines of bit patterns, producing the display. In this way, the software allows the eight LEDs to emulate an 8-by-80...
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Dennis Myer
[POV: Point Of View] PACs Address Increasing Green Monitoring Requirements
With the world’s escalating focus on climate change, ever-evolving environmental regulations, and the birth of new markets such as carbon trading, there has been a significant and rapid increase in the demands for environmental monitoring tools and the applications for which they are used. Programmable automation controllers (PACs) can solve these unique challenges. REMOTE MEASUREMENTS, NETWORKING ABILITIES To comply...
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Joel Shapiro
[Editorial] The Very Old And Very New Converge At Belgium’s IMEC
Though I’m interested in both history and technology, it’s unusual for both of those interests to be served side by side. But upon arriving in Leuven, Belgium, recently for the Interuniversity Microelectronics Centre’s (IMEC’s) annual technology review meeting, I could not help but be struck by contrasts between the very old and the very new. Leuven, the provincial capital of Flemish Brabant, is an utterly charming college town dominated by its Catholic...
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David Maliniak
[Pease Porridge] Bob's Mailbox
BOB, I’ve once again bumped into the limit of an op amp. A single op amp can provide gain or level shifting but not both at once. (I tend to disagree. A single op amp can do a lot of things. It can pat its tummy and rub its head and hop up and down on one foot and provide gain and offset. /rap) I’m feeling around for a way to do a circuit. Depending on what is happening at the time, one end or the other of the resistor may...
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Bob Pease
[TechView: Analog & Power] Fast ADC Sips Power, Simplifies Design-In
For portable applications as diverse as medical imaging units, professional video cameras, batterypowered software-defined radios, and industrial test and measurement designs, the 14-bit, 125-Msample/s LTC2261 analogto- digital converter (ADC) from Linear Technology dissipates 127 mW—less than one-third the power of alternative chips. The company acknowledges that much of the power savings arises from running the LTC2261 at 1.8 V (...
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Don Tuite
[TechView: EDA] Custom Sources Light Way To 22-nm IC Lithography
Concern is rising about the ability of today’s microlithography equipment to scale below 45-nm design rules and still print with acceptable fidelity. There are different schools of thought on how best to meet this challenge—some more hardwarecentric, others more software-centric, and still others combining elements of both. Thus, there has been a spate of announcements of late in this arena (see “IBM And Mentor Graphics Team Up On 22-nm Computational ...
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David Maliniak
[Design FAQs] Multiservice Router Clock Circuit Design Challenges
What’s a multiservice router/ switch? Multiservice routers and switches are network devices that support multiple switching and routing protocols, typically adding Multiprotocol Label Switching (MPLS) and Asynchronous Transfer Mode (ATM) switching to basic Internet protocol (IP) routing services (see the figure). From an IT-services (information ...
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Don Tuite
[Engineering Essentials] Process Technology Considerations For PHY ICs
A careful evaluation of process technology options is imperative to meet the insatiable demand for speed, features, and lower cost in data transmission and telecommunications ICs. High switching speeds, low noise and power consumption, and dense passive devices are critical needs for high-speed ICs used for physical-layer (PHY) applications. These include laser drivers and phase-locked loops (PLLs) for the transmitter and transimpedance amplifiers (TIAs) and...
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Samir Chaudry
[Engineering Essentials] Challenges Lie Ahead At The Physical Layer
The physical layer (PHY) of the Open Systems Interconnect (OSI) model conveys the bit stream—electrical impulse, light, or radio signal—through a network. In the context of the OSI model, the PHY embraces the physical as well as the signaling aspects of the interconnect. Here, we will focus just on the electrical issues. These days, designers are usually most concerned with serial signaling. This came about as data volumes increased and parallel buses just...
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Don Tuite
[EEPN In Electronic Design] Hairy Gecko Peds Hold Key To Powerful Dry Adhesives
Imagine a dry compound that can conductively bind components to a printed-circuit board without the high heat associated with various soldering processes. Or, how about an adhesive that never dries out in a vacuum—a common problem in aerospace applications? For the adventurous, imagine wearing a suit that would allow you to easily scale walls and hang from ceilings like a superhero. These fantasies may not be too far from reality as scientists look to the...
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Mat Dirjish
[EEPN In Electronic Design] Select The Right Circuit Protection For Switch-Mode Power Supplies
Switch-mode power supplies (SMPS) continue to replace linear-regulator types in a host of applications. As the need for more efficient electronics accelerates and as a result of their size, weight, and energy-saving advantages, SMPS are being widely used in applications such as LCD TV monitors, PC/ laptop displays, portable electronics chargers, printers, DVD recorders, and even automotive electronics and industrial. Yet because these new SMPS lack the...
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Stephen J. Whitney
[Lab Bench] Are Designers Making Multicore More Complicated? Or Less?
Multicore is the wave of the future, with more cores in our designs as time goes on. Some push the limits, while others creep up to a half-dozen very large cores. And then there’s the problem of programming these things. Communication lies at the heart of the matter. Memory is the key in a symmetrical multiprocessing (SMP) or non-uniform memory access (NUMA) environment. In other architectures, communication may be packet switches, FIFOs, or a host of...
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William Wong
