A Note From the Editor

Welcome to the 55th issue of Analog Dialogue.

My hope is that 2021 will bring us toward normality, and that a COVID vaccine will become globally available. Even with a vaccine, the next challenge will be to ensure a large enough supply, first for at-risk individuals and caregivers, people working with the public such as teachers and bus drivers, and then for the rest of us. My hope further includes that we learn from this pandemic and recognize that coming challenges can be addressed through open discussion, tolerance, learning from science, and acting accordingly. In that spirit, I wish you all a good start to 2021. Stay healthy, be encouraged, and act with determination and hope.

Back to the articles from Analog Dialogue.

There is some good news: over the coming years, high sample rate analog-to-digital converter (ADC) and digital-to-analog converter (DAC) technology will usher in a wideband digital receiver architectural evolution. These new devices will maintain the excellent linearity, noise performance, and dynamic range of legacy lower rate digital converters. The workhorse superheterodyne tuner will give ground to direct sample and direct conversion architectures. Adaptive spectral tuning will continue to shift from the RF to the digital signal processing realm. This sea change in RF front-end architecture will enable size, weight, power, and cost (SWaP-C) benefits manifesting as higher receive and transmit channel counts at lower cost per channel, in the same or smaller form factors as today. Anticipating the coming era of digital receivers with multi-octave bandwidth, this article discusses new challenges and considerations when designing for best-in-class dynamic range.

Every electronic engineer is familiar with the triangle. This symbol stands for one of the most used devices in the analog domain: the operational amplifier. But, wait a minute–isn’t the same symbol also used to represent a comparator or an instrumentation amplifier? Correct. So what’s the difference, and how can it be identified in a schematic? There are about 700 op amps, 122 comparators, and 63 in-amps to select from. This article takes a closer look at the triangle symbol and what to be cautious of when choosing the right part.

EMI from switching regulators is broken down into radiated and conducted emissions (CE). Conducted emissions can be further classified into two categories: common-mode (CM) noise and differential-mode (DM) noise. EMI mitigation techniques that are effective for CM are not necessarily effective for DM, and vice versa, so identifying the source of conducted emissions can be essential. This article presents a practical method of separating CM emissions and DM emissions from the total conducted emissions. Knowing where the CM and DM noises appear on the CE spectrum enables power supply designers to effectively apply EMI suppression techniques.

One of the most ubiquitous challenges in countless industrial, automotive, instrumentation, and other applications is how to properly connect a minuscule transducer signal to an ADC for digitization and data acquisition. The transducer signal is usually weak, fragile, sometimes noisy, and may look like a very high impedance source, which can be on top of a huge common-mode voltage. None of these are conducive to an ADC input. This article proposes a recent, integrated solution that might once and for all answer an engineer’s plea for help beyond what is currently available. We detail the design steps in order to configure a complete transducer interfaced in-amp to drive an ADC input.

A current source generates a current that is independent of the voltage changes across it. The objective of this issue's StudentZone article is to investigate the use of the zero-gain concept to produce an output current that is stabilized (less sensitive) to variations of the input current level using a bipolar junction transistor and NMOS transistor.

And as we have for 55 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.