A Note From the Editor

Welcome to the June issue of Analog Dialogue.

While reading this issue’s Rarely Asked Question (RAQ) about overvoltage and undervoltage protection, I thought about all the RAQs we have generated over the years. We have addressed over 175 rarely asked questions. In the first RAQ, written in June 2005 by James Bryant, we learned about radio frequencies (or how to get a free lunch at a very good restaurant). James was an applications manager until his retirement in the year 2009. James had written about 40 or more RAQs. I had the honor to train under his leadership in 1989. RAQs cover many interesting topics about electronics. Scan through and you’ll find topics that include capacitors, resistors, transformers, inductors, op amps, ADCs, DACs, and nearly every active or passive component. I sometimes wonder if we’ll come across a shortage of new topics, but I’ve learned that the themes are endless. If you have a suggestion for a rarely asked question, please let me know.

And now, back to the articles from the Analog Dialogue:

In Part 2 of the 3-part series, Phased Array Antenna Patterns, we discuss grating lobes and beam squint considerations, along with the impact of phase shift vs. time delay for wideband systems. In Part 1 in May, we introduced beam pointing and the array factor. Part 3, in next month’s Analog Dialogue, will discuss tapering as a method to reduce sidelobes, and also provide insight on the impact of phase shifter quantization errors.

In case you are working with conditioning-based monitoring systems, you would generally need a complete network to analyze the data (for example, the vibration data from a motor). Sometimes the analysis can be done more easily than one might think. This article describes how to use LTspice® to analyze the frequency content of vibration data in condition-based monitoring systems in order to give early warning of motor failure in industrial machinery. The article explains how to take the X, Y, and Z plane data from a spreadsheet, format it for LTspice, and then apply a Fourier transform to produce a plot of the harmonic content of the vibration data.

With careful IC selection, it is possible to produce compact, high performance power supplies for automotive applications without the usual trade-offs. That is, high efficiency, high switching frequency, and low EMI can all be achieved. The solutions shown in this article use the LT8636, a 42 VIN, 5 A continuous monolithic step-down Silent Switcher® device with a unique layout. The VIN pins are split and placed symmetrically on the IC, splitting the high frequency hot loop while mutually canceling the magnetic fields to suppress the EMI radiated emission.

This month’s RAQ poses the question: are there overvoltage (OV) and undervoltage (UV) protection devices available, especially for automotive applications? Undervoltage and overvoltage could easily occur in many applications. On an automotive supply line, ignition cranking during startup and load dumps during shutdown are common sources of voltage transients. These UV and OV transients can have significant magnitudes and will damage circuits that are not designed to operate during these extremes. Specialized UV and OV protection devices have been developed to disconnect sensitive electronics from power supply transients.

Bipolar transistors are an important component of nearly every circuit. The common-emitter configuration is the base application that every engineer should understand. Antoniu and Doug have generated a nice setup with a 2N3904 transistor, and they explain the results of the basic schematics in a simple to follow way.

And as we have for 54 years, we invite you to be part of the dialogue in Analog Dialogue. You can get in touch through our blog, Facebook page, or email. Let us know how we’re doing and what you’d like to see from us in the coming months.