LM201

"Jamie"

** The world still uses hundreds of thousands of 6L6 tubes every year - first sold by RCA in 1936.

Now made ( in various versions) only by one Chinese factory and a couple more in Russia.

Two 6L6GCs in push-pull can output 100 watts of clean, sine wave power from a few mWs of drive.

.... Phil

The LM201 really was good - designed by Widlar. Much better than the

555.

-- Bill Sloman, Nijmegen

...

The current available part is LM201A, not quite the original, though. This part (LM101/LM201/LM301) was an early single-supply=20 op amp, common mode range included (+) power rail.

Isn't "better" here kind of meaningless? The 555 is certainly a better programmable timer than an opamp is, and AFAIK, the 555 makes a pretty crappy opamp.

Thanks, Rich

The input common mode range did include the positive rail, though National wouldn't guarantee it - read the dats sheet. It wasn't intended to be any kind of single supply part. Widlar went on to develop the single rail op amp - LM124 - and comparator - LM139 and the rather nice LM10.

The one weakness of the LM101 rgne was the absence of an internal compensation capacitor. Fairchild got there first with the decidedly inferior uA741, which - despite a truly horrid output stage - proceeded to dominate the market for years, and the LM307 never got a look in.

-- Bill Sloman, Nijmegen

The LM201 was a useful op amp back then, and there are applications - though not very many - where I'd use it today.

The 555 was always a not-very-good timing circuit bundled with a not- very-good switching transistor. It filled a gap in the market that went away around 1980, and nobody has used it in an original design since then. There are - of course - a lot of copy-cat designers who still don't know better.

If worse than pretty much any other programmable timer that you can still buy ...

and if you knew a bit more, you'd be aware that this isn't the kind of "better" that I'd be talking about.

Jamie made the mistake of calling the 555 a "good" thing, which was never true. It was a saleable thing back when Hans Camenzind invented it, but it's strength lay in the convenient combination of a just-good- enough timer with a just-good-enough NPN saturating switch transistor, and it became a legacy part around 1980. Some of us have yet to notice this.

-- Bill Sloman, Nijmegen

Alright, so if you had a requirement for a variable duty cycle (50-90%) oscillator around 30kHz, what would you use instead of a 555?

Just curious.

Grant

Slowman wouldn't. He's an unemployed (and unemployable) old hen.

t.

e

he

Depends on the application. These days there's usually a microcontroller in there somewhere. The last time I had to produce something that needed to be timed, I stuck a 32,768Hz watch crystal onto the programmable logic device I needed anyway, and used a couple of the cells to make a counter.

-- Bill Sloman, Nijmegen

it.

me

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Krw is attached to his delusions - if somewhat detached from reality. He and Rich Grise think that calling me a communist says something about me, when it actually reveals that both of them stopped processing information from the outside world sometime around 1960, back when I'd just got into university, and had got to meet a number of other people who also thought that calling people "communist" showed a certain lack of imagination.

-- Bill Sloman, Nijmegen

Which kind then?

You can't go even one post without putting in your dig, can you? You're practically indistinguishable from Thompson.

Thanks, Rich

Apparently, he'd use an LM201. >:->

Cheers! Rich

Abstract design quality - incorporating ideas that weren't then obvious to those skilled in the art. Bob Widlar's stuff was always a bit surprising and unexpected. Hans Camenzind is good but not in the Barry Gilbert and Bob Widlar class

You probably do find me practically indistinguishable from Thompson, since you - like him - are way out of touch with reality. "Getting in a dig" at someone who is silly enough to claim that I'm an "admitted communist" - which is a fatuous claim at so many levels that it is hard to know which one to start laughing at first - is more or less obligatory around here.

It is perhaps a waste of time to remind you that if you call somebody an "admitted communist" you are obliged to come up with a quote from the place where you thnk that he admitted to being a communist. You are such a flake - in the krw class - that you will never even bother to try, thus depriving us of the good laugh that would have accompanied the revelation of the moronic misunderstanding that lead you to make the bizarre claim in the first place.

-- Bill Sloman, Nijmegen

Then, how do you explain the fact that Mouser has in stock over 140,000 of them in various packages and manufacturers with prices ranging from $.18 to $.50 ready to ship at this moment? Do you think this is 1980 stock? I think not, since most of the packages were not even available back in the '80s.

As much as I respect you, Bill, I think you are terribly wrong on this subject. The device continues to be useful and is apparently designed into products today. It must be convenient for some applications you have not considered.

Cheers, John

Then, how do you explain the fact that Mouser has in stock over 140,000 of them in various packages and manufacturers with prices ranging from $.18 to $.50 ready to ship at this moment? Do you think this is 1980 stock? I think not, since most of the packages were not even available back in the '80s.

As much as I respect you, Bill, I think you are terribly wrong on this subject. The device continues to be useful and is apparently designed into products today. It must be convenient for some applications you have not considered.

Cheers, John

Oh, I meant to provide this link:

"John KD5YI"

** According to the designer of the NE555, Hans Camenzind, there are about 1 billion 555 chips sold every year - that makes it easily the world's biggest selling IC.

See interview excerpts at bottom of page.

.... Phil

Oh, that link is a beauty, Phil. Thanks!

John

** No problemo.

Da Slow Man has the hide of a Rhinoceros and about the same IQ.

.... Phil

I just did. The 555 was designed into a lot of products between the time it was introduced - early in the 1970's - and the time better gear for doing its job became available around 1980. Some of these products are still in production - legacy products - using 1970's packages. More of them have been minimally redesigned to make the printed circuit board smaller, or to take advantage of better components, but where the 555 did an adequate job, minimal redesign would just change the layout to accommodate a smaller modern package - giving us legacy designs.

Really high volume products, that get made in batches of 100,000 - like TV sets - are worth redesigning completely to shave a few cents off the component cost, but a great deal of stuff doesn't sell in enough high volume to cover the cost of a thorough-going re-design, and designing out a 555 isn't going to shave much off the component cost.

Then we've got legacy designers, who once solved a problem by designing in a 555, and are still solving the same problem today with the same circuit and a CMOS 555 in a surface mount package.

None of this makes the 555 a part that anybody ought to design in.

I've never actually designed in a 555 - I used to look at it from time to time but there was always some good reason for using something better. I've made some wrong choices, but choosing not to use a 555 isn't one of the choices that ever came back and bit me. Several of the serious designers on this group have reported similar experience. John Fields still thinks that the 555 is magic, but he isn't known for pushing the boundaries.

It's certainly convenient to re-cycle old designs. It's unlikely to give you an optimal design, but it's also unlikely to embarrass you by doing something unexpected. The 555 worked back in 1971 - which is how it got to be so popular - and it still works just as well now. Nowadays, lots of other thing work better.

-- Bill Sloman, Nijmegen