Analog Hotspot

Hi Bob! I have been reading and enjoying your stuff for many years! In this case (see "What's All This C-R Stuff, Anyhow?" Sept. 1, 2006, p. 18), I would say that capacitance has varied, not with frequency, but instead with applied potential. Various materials, especially ceramics, vary capacitance with applied voltage. (Yeah, but only a few percent... /rap) If we give cap time to charge up some, its capacitance can vary dynamically. (There ...

I can't believe it took me so long to write this column. I designed some good, low-frequency phase-locked loops (PLLs) about 33 years ago and wrote them up but never got it published. When I moved from Philbrick to National 30 years ago, I got some good voltage-to-frequency converters going, using the new LM331. I also wrote application note AN-210 (still in print) about 1978, which you can see at ...

Some fascinating developments have reverberated within the world of audio this year (see "Multichannel Audio, DDS Keep DACs Humming" at www.electronicdesign.com, ED Online 11763). For one thing, the trend toward more channels in home-entertainment systems has somewhat reversed itself, thanks to ever-more sophisticated algorithms for "virtualizing" speakers. A certain "spousal acceptance factor" worked against installing all of the speakers that came with a 5.1...

The QF1D512 SavFIRe configurable finite impulse response (FIR) filter chip can follow any analog-to-digital converter (ADC) in industrial monitoring applications like vibration sensing, flow measurement and leak detection, medical patient monitoring and diagnostics, seismic, and sonar. Drawing the "Sav" part of its name from "simple and versatile," this Quickfilter chip also can be used as a co-processor device for controllers that have embedded ADCs. Its companion...

Do you believe that the real analog engineering shortage is at the PhD level? Ken Connor (RPI): Not exactly. There is indeed a shortage of people who can do real analog design. This has been the case for years. Students get jobs as BS grads, but only if they already have some good practical experience. I see the trend as companies hiring grads who know something. We have been very lucky and recently hired two analog-circuit...

This job description comes from True Circuits' HR Req: MSEE required, PhD preferred with 5+ years experience in mixed-signal IC design, with emphasis on analog design Experience with several analog/mixed-signal IC development cycles including design, simulation, layout, and testing Knowledge of PLLs, DLLs, oscillators, SERDES, I/Os, controllers, and high-speed digital circuits ...

"Good analog engineers require mentoring. The best are the guys who fooled around with electronics on their own before they went to college." "Since I am the only ‘analog engineer’ and we cannot afford to buy another one, I spend about 10 to 20 hours a week handling the analog design tasks." "There isn’t a high demand for just analog engineers. I’ve noticed that most industries now want an engineer who knows...

Is there a shortage of analog engineers? Some industry data suggests there is. But when Electronic Design asked its readers earlier this year if their organization is having difficulty finding qualified analog engineers, more than half said they do not. In fact, 1620 of the 2354 readers (69%) said that they perceived no shortage. So while there may be a shortage, it clearly doesn't affect all companies equally. Possibly, that's because most engineers today deal exclusively with the...

Based on your submissions, designers everywhere face the same challenges— producing more functionality-while maintaining an elegant design. The latest project at Intelix, the Audisey Series Athena, exemplifies these demands. Available later this year, the Athena provides microphone preamplification, input DSP, true matrix mixing, output DSP, and amplification all in a 3U chassis. It uses a DSP/Class D amplification module, which is the heart of the project. ...

Microcontrollers continue to shrink in size and cost. For example, Microchip's latest six-and eight-pin PIC10Fs have a footprint of only 2 by 3 mm, which is 30% less than a SOT-23 package (Fig. 1). Many discretes are larger than these devices. Because of an on-chip oscillator, these microcontrollers can utilize all of the pins except for the power and ground pins for peripherals. This is critical when the number of I/O pins...

What do you call a family of 900-kHz, selectable-gain amplifiers that provide a gain-select pin in place of a negative-input pin? Microchip Technology calls it the MCP6G0x family, with single, dual, single with chip select, and quad models. The company offers these devices as drop-in replacements for op amps, as microcontroller-controlled amplifiers, or as standalone gain blocks. The MCP6G0x amplifiers operate from 1.8 to 5.5 V with a 110-µA quiescent...

One challenge in using delta-sigma analog-to-digital converters (ADCs) is that their input sampling currents can overwhelm high source impedances or low-bandwidth, micropower signal conditioning circuits. Last year, Linear Technology came up with an "Easy-Drive" family of delta-sigmas that addressed this problem by balancing the ADC's input currents (see the figure). The latest member of this family, the 24-bit LTC2498,...

Power-One has gained an ally for its Z-One digital intermediate bus architecture (IBA) standard. Micrel's MIC68000 family of linear regulators are interoperable with Power-One's Z-One point-of-load converters (POLs) and ZM7300 digital power managers. Until now, power-system designers could use only Power-One's switching POLs to take advantage of the Z-One concept. The virtue of Z-One digital IBA has always been its comprehensive control of POL sequencing, tracking, and slew rate,...

Michael J. Therien, a professor of chemistry at the University of Pennsylvania, is taking a colorful approach to the chip density barriers that threaten to repeal Moore's Law. As conventional semiconductor technology reaches its natural limits, Therien believes that the future of high-speed electronics lies in "electrically jumpy" molecules known as chromophores. A chromophore is the part of a molecule that's responsible for its color. When light hits a chromophore, it excites an...

Recently, people in various publications have been pointing out that using an ordinary op amp in a Sallen-Key filter can cause problems. A typical op-amp circuit, as shown in Figure 1, can have a frequency response that rolls off nicely above 1 kHz, at 12 dB per octave, down to ?40 or ?50 dB. Then the response may roll back up or stay flat at higher frequencies. If you choose a fast op amp with high Ib, you might choose low...

Functionality is converging on platform devices as they become our primary conduits for voice, data, and video. This increase in functionality drives the need for more integration in both digital and analog ICs. From a process technology perspective, digital's demands are relatively straightforward: deliver more bits per area by taking advantage of advances in lithography. Analog's demands are more complex, as analog encompasses the RF interface, data conversion, and...

Hi Bob: In today's Wall Street Journal, there's a full article on A4 concerning hydraulic hybrids. It was developed by the EPA, which has a small lab. UPS trucks are being used for testing, but garbage trucks will be the first commercial use. (I wonder what the standard "driving cycle" is for a UPS truck. It must be quite different from the EPA cycle for cars. Many parts of that cycle might have a lot of stopandgo, but not all—not to mention the typical garbage...

Conventional wisdom (and your neighborhood venture capitalist) says you can't go to market with a new product until you have a business plan, a second mortgage, an offshore manufacturing contract, and sales projections that guarantee 20% return on investment (for the VC). But here's a wireless product that an engineer with a day job worked up on his home workbench in his spare time. He then productized and released it to a domestic manufacturer that markets it through a small...

A resistor is a resistor, and a capacitor is a capacitor, right? Maybe, and maybe not. I'm doing some research in audio circuits. I've heard all the scientific claims that if two circuits measure the same, they ought to sound the same. This claim is refuted by the observation that they don't sound the same. That's a pretty convincing rebuttal. I gotta believe it. I'm an analog and measurement guy. If somebody says some audio circuits don't sound the same, I bet...

Input crossover distortion has long been the bane of rail-to-rail op amps. The input stage for most R-R amps consists of p-and n-channel differential pairs (Fig. 1a). The result is that the stage's offset voltage varies with the common-mode input voltage. The nonlinearity as the input signal passes through the crossover point limits the amplifier's total harmonic distortion (THD) (Fig....