Analog Design Not Dead

I’m not much of a party person but there are occasions when one’s presence is required – and some parties can even be fun if you keep an open mind about it. (Just beware of an open bar on an empty stomach, that can be deadly.) At one party, I asked one of the guests what he did: ‘I’m an astrophysicist’ he said. I guess I looked astonished because he added’Well, someone has to do it.’ True enough. (See the movie Star Men for a nice take on that.)

Anyway, if someone asks me at a party what kind of electronics I do I may say ‘analog circuit design’, and then the response might be ‘I thought analog had been replaced by digital’. Well, no.

Those comments have come back to me as I’ve been sweating over various analog circuits for the last few weeks. The PSM-101 power supply has a major analog circuit, the scopes have preamps and signal generators, the curve tracer is full of analog circuits. One of our products in development has 18 op-amps and a bunch of discrete transistors. Op-amps have greatly simplified analog circuit design. I’m old enough to remember when the one of the first integrated circuit op-amps (the Fairchild uA709) arrived at our workplace. It came in a jewel box and cost about $100. Everyone was terrified of using it. That’s changed over the years: one of our op-amp favorites, the TL074, is under a buck for a quad op-amp package. But analog circuit design is more than plugging an op-amp and some discrete components into a circuit board. We struggled for over an hour one evening to find the source of a mysterious offset, which turned out to be op-amp bias current (a rookie mistake on my part).

Microprocessor systems are easier to get working, and to do something significant with relatively modest circuit design effort and some programming. So the world is full of Arduinos and other Fruity Computers doing wonderful things, much of it accomplished by beginners – which is great stuff. (Beware, however, computer coders: big programs are not just bigger small programs: they are qualitatively different. You need to plan and design them.) But if you want to be a designer of electronic systems, you need to know both: digital *and* analog. For one thing, you need to be able to choose: sometimes one op-amp can replace hundreds of lines of computer code — and work better. Other times, you need the flexibility of software to reduce the demands on the analog circuitry.

It takes some time to become an analog circuit designer. Analog design is a nice mix of theory and practice. There is always new stuff to learn, which is one of the attractions. It helps to like tinkering with circuits (the best way to learn) and to be endlessly curious.

That said, this is a great time to do analog circuit design: loads of information on the web, readily accessible parts catalogs and suppliers, free circuit simulators, inexpensive components, and terrific instruments for your workbench. Go for it.

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