A technical discussion on analog signal processing circuits and solutions
    • Jun 25, 2013

    Knowing Where to Tap

    Jake, a respected veteran engineer in a power generation plant, retired with great congratulations and accolades. A few months later the plant suffered a major malfunction—a real meltdown with all systems involved. The engineering staff could not quickly diagnose the problem so with due urgency they called Jake for an emergency consultation. ...
    • Jun 17, 2013

    Pop Quiz!

    Put away your books and take out a sheet of paper. Each question relates to one of The Signal blogs over the past 15 months. If you have difficulty answering, click on the link to bootstrap knowledge on the topic. Answers are at the end so you can score yourself. Have fun! 1. A gain of -0.1 (inverting) amplifier… a) is very likely to...
    • Jun 11, 2013

    Settling Time

    Settling time is the time required for an op amp to respond to an input voltage step, enter and stay within specified error range of the final value. It’s important in applications that drive an a/d converter, digitizing rapidly changing inputs. But let’s look beyond the definition and focus on the character of settling waveforms. Last...
    • Jun 3, 2013

    Slew Rate—the op amp speed limit

    Slewing behavior of op amps is often misunderstood. It’s a meaty topic so let’s sort it out. Click Here to read on EDN Magazine web site. 60+ interesting The Signal topics.
    • May 21, 2013

    Grounding Principles

    In a previous blog on supply bypassing , I cautioned that poor bypassing could increase distortion of an amplifier. A reader, Walter, asked an interesting question… where should you connect the ground of a bypass capacitor to avoid problems? This raises questions regarding proper grounding techniques. Wow. Big topic, but I may be able provide...
    • May 13, 2013

    Handy Gadgets and Resistor Divider Calculations

    Handy gadgets make our engineering life easier—the little special purpose computer programs or spreadsheets that you might find or create yourself. Back in the old days, engineers used nomographs. These are graphical aids that solve common multivariable problems of all sorts. Calculators and desktop computing caused their decline so you seldom...
    • May 6, 2013

    Chopper Op Amps—are they really noisy?

    Chopper op amps offer very low offset voltage and dramatically reduce low frequency 1/f (flicker) noise. How do they do it? Here’s a quick-read on the tricks. Click Here to read on EDN Magazine site.
    • Apr 23, 2013

    Bypass Capacitors… yes, but why?

    Everyone knows that op amps should have power supply bypass capacitors located near the IC’s terminals, right? But why? Why, for example, is an amplifier more apt to oscillate without proper bypassing? The reasons will increase your understanding and awareness. Power supply rejection is an amplifier’s ability to reject variations in the...
    • Apr 16, 2013

    Rail-to-Rail Inputs—what you should know!

    Rail-to-Rail (R/R) op amps are extremely popular, especially useful with low supply voltage. You should know how R/R inputs are accomplished and understand some trade-offs. Figure 1 shows a typical dual-input R/R stage comprised of both N and P-channel transistor pairs. The P-channel FETs handle the signal through the lower portion of the common...
    • Apr 7, 2013

    Op Amps… G=1 stable & decompensated

    You have voted. Unity-gain-stable op amps won in a landslide—they’re far more popular than decompensated op amps. What’s this all about? Click Here to read on EDN Magazine site.