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Multisim 11 is the latest version of its circuit simulation software, with specialized editions for both hands-on learning and professional circuit design. The easy-to-use Multisim software delivers a graphical approach that abstracts the complexities of traditional circuit simulation, helping educators, students and engineers employ advanced circuit analysis technology. The academic edition of Multisim 11 incorporates specialized teaching features and is complemented by circuits textbooks and courseware. This integrated system helps educators engage students and reinforce circuit theory with an interactive, hands-on approach to investigating circuit behavior. Multisim 11 Professional helps engineers optimize circuit designs, minimize errors and reduce prototype iterations. When combined with the new NI Ultiboard 11 layout and routing software, Multisim provides engineers a cost-effective, end-to-end prototyping platform. Its integration with NI LabVIEW measurement software also helps engineers define custom analyses to improve design validation…

Breadboarding a new circuit is a key skill and an important step in many projects—especially early on, when you need to move wires around and substitute components. But that very flexibility also makes it easy to knock wires out. Eventually, if your project is a keeper, you’re going to want something with a bit more permanence. Printed circuit boards (PCBs) solve all those shortcomings. But most people don’t even consider translating a one-off project into a PCB design. For one thing, PCB fabrication has traditionally been expensive, viable only in commercial quantities. (One alternative is to do it yourself with etches and silk screens, a messy and time-consuming process.) Also, there are technical constraints involved with PCB designs that are daunting to the casual hobbyist. But it turns out that nowadays you can produce a professional PCB very inexpensively.

Three-dimensional microchip designs are making their way to market to help pack more transistors on a chip as traditional scaling slows down. By stacking logic chips on top of one another other or combining logic chips with memory or RF with logic, chipmakers hope to sidestep Moore's Law, increasing the functionality of smartphones and other gadgets not by shrinking a chip's transistors but the distance between them. "There's a big demand for smaller packages in the consumer market, especially for the footprint of a mobile phone, or for improving the memory bandwidth of your GPU," says Pol Marchal, a principal scientist of 3-D integration at European microelectronics R&D center Imec. On 9 February, at the IEEE International Solid-State Circuits Conference (ISSCC), in San Francisco, Imec engineers presented some key design challenges facing 3-D chips made by stacking layers of silicon circuits using vertical copper interconnects called through-silicon vias (TSVs). These design constraints will have to be dealt with before TSVs can be widely used in advanced microchip architectures, Marchal says.

With the introduction of the WEBENCH Online Design Environment in 1999, National Semiconductor made it possible for design engineers to create a reliable power supply circuit over the internet in minutes. The user specified the circuit performance and the WEBENCH Toolset delivered. Today, WEBENCH Designer creates and presents all of the possible power, lighting, or sensing circuits that meet a design requirement in seconds. This enables the user to make value based comparisons at a system and supply chain level before a design is committed. This expert analysis is not possible anywhere else.

Harmonic balance (hB) analysis is a method used to calculate the nonlinear, steady-state frequency response of electrical circuits. It is extremely well-suited for designs in which transient simulation methods prove acceptable, such as dispersive transmission lines in which circuit time constants are large compared to the period of the simulation frequency, as well as for circuits that have a large number of reactive components. In particular, harmonic balance analysis works extremely well for microwave circuits that are excited with sinusoidal signals, such as mixers and power amplifiers...

The design of a generator system requires many hours of detailed planning with the goal of creating an extremely reliable backup power source. Properly installed, the system will deliver the intended level of reliability. However, if incorrectly wired, the system can become a problem for both the owner and the manufacturer. While the generator installation can be handled by a range of people, from a trained technician to the typical homeowner, wiring mistakes can occur. Installation includes working with 120 VAC split phase, 240 V line voltage, along with low-voltage signals below 50 V. A small and easily made mistake, such as miswiring high voltage to low voltage, will destroy sensitive electronics quickly and may render the equipment inoperable. Thus, a resettable overcurrent and overvoltage solution capable of handling line voltage, electrostatic discharge (ESD), electrical fast transients (EFT), and current surge is required to protect low voltage interface circuits against this problem.

LED luminaires require precise power and heat management because LEDs convert most of the electrical energy they receive into heat rather than light. Without adequate thermal management, this heat can degrade the LED's life span and affect color output. Also, LEDs can fail short because they are silicon devices, so they may require fail-safe backup in the form of overcurrent protection. Resettable PPTC (polymeric-positive-temperature-coefficient) circuit-protection devices have demonstrated their effectiveness in a variety of LED-lighting applications. Like traditional fuses, they limit current after they exceed specified limits. However, unlike fuses, PPTC devices can reset after the fault clears and the power cycles.

This article features an example chapter from a new *Hot-off-the-Press* book on FPGA Design that just recently hit the streets in August 2010. This chapter is reproduced here with the kind permission of the publisher – Springer. This book -- FPGA Design: Best Practices for Team-Based Design -- describes best practices for successful FPGA design. It is the result of the author’s meetings with hundreds of customers on the challenges facing each of their FPGA design teams. By gaining an understanding into their design environments, processes, what works and what does not work, key areas of concern in implementing system designs have been identified and a recommended design methodology to overcome these challenges has been developed.

Simple mathematical analysis shows that the best answer to address this problem is to  select a CR ratio QGD/QGS1 that is less than 1. Other factors to consider for preventing C dv/dt induced turn-on include low driver-sinking impedance (<1 Ώ), a FET design with intrinsically low RG, an externally-applied G-S capacitor and Q2 packages that minimize parasitics and voltage ringing.

Ted Marena of Lattice Semiconductor Corp., points out that designers of digital systems are familiar with implementing the 'leftovers' of their digital design by using FPGAs and CPLDs to glue together various processors, memories, and standard function components on their printed circuit board. In addition to these digital functions, FPGAs and CPLDs can also implement common analog functions using an LVDS input, a simple resistor capacitor (RC) circuit and some FPGA or CPLD digital logic elements to create an analog to digital converter (ADC).

Linear and nonlinear device models are costly and time-consuming to develop. Most compact model parameters are extracted from linear, 50-ohm S-parameters and predicting behavior under extreme nonlinear conditions or non-50 ohm terminations is unreliable. This white paper entitled "X-parameters and Beyond, AWR's Support of PHD and Nonlinear Behavioral Models," provides details on rapidly-emerging nonlinear models and measurement systems and how Thye are employed in AWR's Microwave Office high-frequency design software.

In high-end audio equipment, careful selection of resistors is one of the best ways to avoid or minimize noise and distortion in the signal path. This paper describes the noise generation in resistors manufactured using the various available resistor technologies and quantifies the noise insertion typical for each type.

A shielded transformer is a two-winding transformer, usually delta"star connected and serves the following purposes: Voltage transformation from the distribution voltage to the equipment's utilization voltage. Converting a 3-wire input power to a 4-wire output thereby deriving a separate stable neutral for the power supply wiring going to sensitive equipment. Keeping third and its multiple harmonics away from sensitive equipment by allowing their free circulation in the delta winding. Softening of high-frequency noise from the input side by the natural inductance

There are severe flaws within the Harmonic-Balance and SPICE programs now widely used. Mentioned as far back as within an abstract of Session WSO at the 2008 IEEE International Microwave Symposium: "Even though nonlinear circuit-analysis software has been in use for many years, users still have difficulty obtaining valid results with existing methods.  Recognized problems include poor accuracy, convergence difficulties, long simulation times, and unstable results (i.e., results that vary greatly with minor changes in parameters).  These problems are encountered in both harmonic-balance and time-domain simulations."

When the Arduino Duemilanove microcontroller appeared in 2005, it featured a set of female pin headers exposing most of the pins of the ATmega168 for easy hacking and for connecting accessory boards known as 'Shields'. The purpose of a shield is to provide new plug-and-play functionality to the host microcontroller, such as circuit prototyping, motion control, sensor integration, network and radio communication, or gaming interfaces, without worrying too much about the hardware implementation details. Seven years after the birth of the original Arduino, new shields keep coming out and are being cataloged on http://shieldlist.org/, a testament to the versatility of the design. It is also simple to build a DIY shield when nothing out there will meet your needs or when you want to understand how the shield concept works from the ground up.