Author Topic: Why is the 741 op amp still produced?  (Read 19663 times)

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Offline Kleinstein

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Re: Why is the 741 op amp still produced?
« Reply #25 on: September 19, 2020, 04:18:50 pm »
There are still a few circuits a round that are made for the 741. There is a lab supply kit (often from China) with TL081 OPs tortured with too much supply because the original circuit was made for the 741 that can stand a higher supply.

For a slightly improved version of the LM358 with less cross over distortion, there is the MC33172 - faster and less distortion, but otherwise similar.

The 741 was just so popular that there is still some demand and it is no magic in making them, even though they are not the cheapest to make and the supply current is rather high for the performance.
 

Offline Rick Law

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Re: Why is the 741 op amp still produced?
« Reply #26 on: September 19, 2020, 06:51:49 pm »
There are posts about "right to repair" now and again.  Right to repair means nothing if parts are not available.  So from that perspective, the longer they can keep making that same something, the better it is for the consumer.
 

Offline Rah_H

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Re: Why is the 741 op amp still produced?
« Reply #27 on: September 19, 2020, 07:18:14 pm »
741 are used in analog function generators. I have a MCP SG1639A 3MHz Analog Function Generator/Counter which has multiple 741s in it complete with IC socket. Old school ICs are still used in a lot of Chinese lab equipment because they are proven to work and are profitable. It doesn't matter if the technology is 30 years old, it is going to serve someone's purpose. So why change it?
 

Offline floobydust

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Re: Why is the 741 op amp still produced?
« Reply #28 on: September 19, 2020, 08:55:57 pm »
It's gotten ridiculous that semi manufacturers optimize one or two things, roll out a new part number. Do we really need 5,000 different op-amps and the hours spent looking at datasheets to find the best part- which ends up being massively overpriced kills the BOM cost, or has long lead-times.

Why is a LM358 $0.15 but a better part over 10x the cost? Do they have more gold-pressed latinum inside?
An op-amp that has true competition has a reasonable price. Multiple-sourced 741, 358, 4558 is also why they are still alive.
 

Offline Kleinstein

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Re: Why is the 741 op amp still produced?
« Reply #29 on: September 19, 2020, 09:51:30 pm »
One problem leading to so many OP variants is that they often behave different in the details. There are quite a few parameters to look at and not always is there a clear better or worse. There are cases when one wants some input bias current (especially a defined sign and order of magnitude). Also faster is not always better.
So the problem is that there is usually no 100% replacement / upgrade. Even if it works in 99.9% of cases it can't replace the original. There are plenty of OP versions that are not really needed any more: e.g. TL082 if there are TL072 (tighter noise specs) at essentially the same price and sometimes even cheaper.

With the serious distributors they even make a difference between the same part from different source (e.g. 741 or LM358 from several vendors with essentially identical specs).

Usually one has a few personal favorites in the head / drawer, so one knows if they are sufficient. One may later change to a more suitable/specific OP (e.g. lower cost), but one may also skip that step. The 741 is likely still in some peoples favorites  / known by hart list. So even if not the best part it is still used. The best 741 substitute is probably still a 741 from a different source.
 
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Offline schmitt trigger

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Re: Why is the 741 op amp still produced?
« Reply #30 on: September 20, 2020, 03:48:20 pm »
The 741 is one of those products that established a standard in its category. It is like the 6L6

And let’s not forget that ubiquitous double triode, the 12AX7/ ECC83.
 

Online NiHaoMike

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Re: Why is the 741 op amp still produced?
« Reply #31 on: September 20, 2020, 06:17:08 pm »
I haven't seen a 741 "in the wild" in a very long time, but I did see lots of 4580s and whatnot on sound cards until digital became the norm.

I suspect a lot of "classic" opamps like the 741 and LM386 are still used in music production specifically for their less than perfect audio qualities.

There are plenty of OP versions that are not really needed any more: e.g. TL082 if there are TL072 (tighter noise specs) at essentially the same price and sometimes even cheaper.
That was once done to sell the parts that fail to qualify as the superior version, but nowadays with much more mature processes, I suspect most of the "inferior" parts are simply remarked to meet demand.
And let’s not forget that ubiquitous double triode, the 12AX7/ ECC83.
We can thank the audiophiles for that. Of course, they're not really after better audio quality when they use tubes, they're after making it sound like the way they remembered it back in the day.
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Offline David Hess

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Re: Why is the 741 op amp still produced?
« Reply #32 on: September 20, 2020, 09:02:52 pm »
The 741 might have been a big deal in its day, but things have moved on. Nowadays we have a zillion different op amps to choose from, ranging from similar to vastly improved performance.

How many of those parts have a maximum supply voltage of 44 volts and a maximum differential input voltage of 30 volts?  These things make the 741 easy to use at higher supply voltages.

There are parts with those characteristics which are significant improvements over the 741, but they are several times more expensive, and even they are 30+ years old.

Things are even worse when you consider the equally old 301A which supports external compensation and clamping unlike anything modern.
 

Offline David Hess

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Re: Why is the 741 op amp still produced?
« Reply #33 on: September 20, 2020, 09:05:58 pm »
Why is a LM358 $0.15 but a better part over 10x the cost? Do they have more gold-pressed latinum inside?
An op-amp that has true competition has a reasonable price. Multiple-sourced 741, 358, 4558 is also why they are still alive.

The 358/324 were optimized from the start for small die size which is why dual and quad parts were even possible.  Improved replacements for them like the LT1013/LT1014 are optimized for performance and are huge in comparison.
 

Offline julian1

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Re: Why is the 741 op amp still produced?
« Reply #34 on: September 21, 2020, 01:49:25 am »
What I find odd, is that there are >8000 op-amp variations available, all trying to exploit vanishingly small and segmented market niches. But it's really hard to find common matched npn/pnp pairs (on the same substrate) in order to implement current mirrors, long tail pairs, differential amps - which are the building blocks of analog circuits and those op-amps. I only know a couple of inexpensive parts bcm846 bcm857, unless I completely fail at parameterized search.     
 

Offline David Hess

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Re: Why is the 741 op amp still produced?
« Reply #35 on: September 21, 2020, 03:41:48 am »
It would sure be nice to have transistors arrays built on the modern 36 volt complementary bipolar process used for rail-to-rail precision parts, high slew rate voltage feedback operational parts, and current feedback operational amplifiers.  For a while after Linear Technology released resistor arrays based on their thin film resistor process, I hoped they would release transistor arrays but they never did, and they discontinued their LT1088 thermal RMS converter.

THAT Corporation sells matched quad transistor arrays in both polarities intended for audio applications which might have acceptable availability, but they are not cheap.

National used to make the LM389 which was an LM386 class audio amplifier plus three uncommitted NPN transistors which was a useful and inexpensive source for matched monolithic transistors.
 

Online EEVblog

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Re: Why is the 741 op amp still produced?
« Reply #36 on: September 21, 2020, 04:37:33 am »
Simple, it's a known quantity and industry standard used by countless engineers for generations.
When you ask "why is it still used", think instead "what would replace it". Better yet, set up a poll and see what results you get, I guarantee there will not be a consensus on an answer.
That non-consensus is why the 741 is still the jellybean opamp choice.
 

Offline floobydust

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Re: Why is the 741 op amp still produced?
« Reply #37 on: September 21, 2020, 05:36:39 am »
Why is a LM358 $0.15 but a better part over 10x the cost? Do they have more gold-pressed latinum inside?
An op-amp that has true competition has a reasonable price. Multiple-sourced 741, 358, 4558 is also why they are still alive.

The 358/324 were optimized from the start for small die size which is why dual and quad parts were even possible.  Improved replacements for them like the LT1013/LT1014 are optimized for performance and are huge in comparison.

I think the main driver is op-amp cost. They can be a huge hit to your BOM costs.

Linear Tech is top quality and extremely expensive.  LT317AT is USD$5.00 and LM317T-DG $0.77 that's a monster difference.
LT1013CN8  USD$5.75 16wk lead-time when it's out, I've had to wait that.
LM358PE4 $0.36 and never out of stock. I don't see the silicon area as the cost multiplier of 16x although I'm not an expert on the process and die sizes. Sure the LT1013 eliminated the PNP O/P tranny and added a bunch of others to crank up the gain. Kudos to LT for having the balls to update the old dog op-amps. I'd pay double or triple the price but no more.
 

Offline David Hess

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Re: Why is the 741 op amp still produced?
« Reply #38 on: September 21, 2020, 08:50:55 am »
Simple, it's a known quantity and industry standard used by countless engineers for generations.
When you ask "why is it still used", think instead "what would replace it". Better yet, set up a poll and see what results you get, I guarantee there will not be a consensus on an answer.
That non-consensus is why the 741 is still the jellybean opamp choice.

The 741 also has better specifications than many similarly priced but modern parts, like its common mode rejection.

Sure the LT1013 eliminated the PNP O/P tranny and added a bunch of others to crank up the gain. Kudos to LT for having the balls to update the old dog op-amps. I'd pay double or triple the price but no more.

The LT1013 is second sourced from TI so has reached a reasonable price.

In production quantities, real precision parts like the LT1097 are a deal.
 

Offline SeanB

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Re: Why is the 741 op amp still produced?
« Reply #39 on: September 21, 2020, 10:23:16 am »
Biggest user is Aerospace, simply because the darn things are rugged, reasonably reliable, are available in rad hard versions, and also are the part that is certified for this application.  gotten them and abused them, and they are rugged, even when using them with 44 volt power rails, so they would be able to output 30V peak to peak, replacing some dead OP20 amplifiers, though i did add the TO100 heatsinks to them to keep them cool, unlike the OP20's, which had cooked nicely.

Yes for general purpose use at lower voltages there are better parts, but for industrial logic with not much required frequency wise, and with a truly big common mode range hard to beat, plus they will survive transients that would kill other opamps, simply because the die is so large.
 

Offline rdl

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Re: Why is the 741 op amp still produced?
« Reply #40 on: September 21, 2020, 02:59:45 pm »
If you've spent hundreds or thousands of hours testing, possibly over several years, to qualify something, then you really don't want to have to do that again because some component is no longer available. This is true no matter what industry you work in or what type of product you make.
 

Offline alsetalokin4017

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Re: Why is the 741 op amp still produced?
« Reply #41 on: September 21, 2020, 04:44:42 pm »
I just bought 20 of them last week. Way overpriced at about 40 cents US each, but fast and free delivery and I didn't have to leave the house to go get them. They are marked like real ST  UA741CN and look genuine on the outside. But I wouldn't know how to tell a fake except if it flat out didn't work, and my intended use case is very undemanding, I hope. I am still playing around with that Chaos Oscillator circuit from another thread. I first built it up with 2 358 chips but the original was done with 4 discrete single-chip opamps, not specified in the paper, but odds are they used 741.

Also I have a bunch of vintage equipment, like my main bench power supply and an IEC signal generator, that has them scattered around in the circuitry in various places. I only had 2 remaining in my IC tin so I went ahead and ordered a handful to play with and for spares.
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Offline magic

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Re: Why is the 741 op amp still produced?
« Reply #42 on: September 21, 2020, 05:34:51 pm »
They are marked like real ST  UA741CN and look genuine on the outside. But I wouldn't know how to tell a fake except if it flat out didn't work, and my intended use case is very undemanding, I hope.
One annoying sort of fakes are LM358 with false markings. Some are normal duals and likely to burn if you plug them into a single socket, others are rewired internally to work as singles. The latter can be spotted by having nothing connected to the offset null pins. A few people already scratched their heads over excessive bias current, noise or crossover distortion in what was supposed to be a TL07x or NE553x.
 

Offline VooDust

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Re: Why is the 741 op amp still produced?
« Reply #43 on: September 21, 2020, 05:43:15 pm »
The 741 might have been a big deal in its day, but things have moved on. Nowadays we have a zillion different op amps to choose from, ranging from similar to vastly improved performance. I can’t remember the last time I saw one in a piece of equipment. And no one with a grip on reality designs them into new products. And even in the case of repairs for old equipment there would surely be modern substitutes available. And get this - I was looking at the TI 741 data sheet and it says the 741 “feature(s) improved performance over industry standards like the LM709.” The LM709 might indeed have been an industry standard fifty years ago but it’s a bit of a stretch to still refer to it as that. We’re in the age of GPUs with 28.3 *billion* transistors. It’s time the 741 was put to bed. It’s fine to read all about it from a historical point of view. That great, but I think school textbooks should stop using it as an example as if it were a mainstream device. But what to replace it with? Over to you.

Yeah it would be great if they stopped writing these "what are the essential op-amps" type blog posts where the 741 ranks on top. I would have gladly paid 50 cents more and get something that works rail to rail, thank you. For beginners anyways.
 

Offline peter-h

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Re: Why is the 741 op amp still produced?
« Reply #44 on: September 21, 2020, 08:49:40 pm »
One would not design-in a 741 today, or anytime since about 1975, but it would be wrong to say the LM358 (which I've been using since c. 1975) replaces the 741 because - for a start - the output voltage swing is very different.

There are rail to rail (on both input and output) op-amps but they are quite expensive. I have just done a design which needs to achieve 16 bit DC precision and a lot of the op-amps cost around $2 each.

As a general comment, the world has moved many years ago from generic (and cheap, multi sourced) parts to high performance (and expensive, single sourced) parts. A clever designer will use the former, and they still exist. A lazy designer will use the latter, and keeps firms like Linear Technology in business :)
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Online Wolfgang

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Re: Why is the 741 op amp still produced?
« Reply #45 on: September 21, 2020, 08:59:55 pm »
One would not design-in a 741 today, or anytime since about 1975, but it would be wrong to say the LM358 (which I've been using since c. 1975) replaces the 741 because - for a start - the output voltage swing is very different.

There are rail to rail (on both input and output) op-amps but they are quite expensive. I have just done a design which needs to achieve 16 bit DC precision and a lot of the op-amps cost around $2 each.

As a general comment, the world has moved many years ago from generic (and cheap, multi sourced) parts to high performance (and expensive, single sourced) parts. A clever designer will use the former, and they still exist. A lazy designer will use the latter, and keeps firms like Linear Technology in business :)

I would agree that the 358s/324s cannot replace the 741s in case crossover distortion is a big issue, but in other cases the advantages are obvious:
- 2/4 instead of one in a single case
- more current
- negative rail included in input and output, thats often enough.
- cheaper
- slightly faster
- lower voltage operation possible (>2.5V)

So, 741 for repair/replace/legacy systems business - why not. New stuff ? Never.
 

Offline Tomorokoshi

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Re: Why is the 741 op amp still produced?
« Reply #46 on: September 21, 2020, 09:26:00 pm »
Let's just say that I made the mistake of using op-amps from Microchip. Once.
 

Offline james_s

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Re: Why is the 741 op amp still produced?
« Reply #47 on: September 21, 2020, 09:40:25 pm »
Let's just say that I made the mistake of using op-amps from Microchip. Once.

I've used them a few times, they worked fine, it was very non-critical applications though. Curious what problems you experienced?
 

Offline coppice

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Re: Why is the 741 op amp still produced?
« Reply #48 on: September 21, 2020, 10:00:41 pm »
The 741 might have been a big deal in its day, but things have moved on. Nowadays we have a zillion different op amps to choose from, ranging from similar to vastly improved performance. I can’t remember the last time I saw one in a piece of equipment. And no one with a grip on reality designs them into new products. And even in the case of repairs for old equipment there would surely be modern substitutes available. And get this - I was looking at the TI 741 data sheet and it says the 741 “feature(s) improved performance over industry standards like the LM709.” The LM709 might indeed have been an industry standard fifty years ago but it’s a bit of a stretch to still refer to it as that. We’re in the age of GPUs with 28.3 *billion* transistors. It’s time the 741 was put to bed. It’s fine to read all about it from a historical point of view. That great, but I think school textbooks should stop using it as an example as if it were a mainstream device. But what to replace it with? Over to you.
The world needs a lot of simple glue chips to sit between the big chips. Time was when 2 input gates only came in packs of 4. These days you can buy a small pack with just one gate in it, responding to the common modern need for just a single gate here and there as glue between complex chips. Billions and billions of simple low performance op-amps are used each year. However, if you ask someone at TI to recommend a simple low performance cheap op-amp they'll probably recommend an LMV321, or an LMV324 is you need several amps. Note than the LM321 is about as old as the 741, but most people use the more flexible LMV321 derivative these days. Nobody recommends a 741 any more, but a lot are still used in equipment whose design hasn't changed for decades.
 

Offline Zero999

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Re: Why is the 741 op amp still produced?
« Reply #49 on: September 22, 2020, 09:58:59 am »
However, if you ask someone at TI to recommend a simple low performance cheap op-amp they'll probably recommend an LMV321, or an LMV324 is you need several amps. Note than the LM321 is about as old as the 741, but most people use the more flexible LMV321 derivative these days. Nobody recommends a 741 any more, but a lot are still used in equipment whose design hasn't changed for decades.
How is the LMV321 more flexible, than the old LM321? It has some advantages: lower power consumption, bias currents and a rail-to-rail output, but the fact it only works up to 5.5V, rather than 30V, severely limits its applications, making it inflexible compared to the old LM321.
 


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