EEVBlog 1436 - The TOP 5 Jellybean OPAMPs - Page 1
Forum section: electronics / general

author: EEVblog
author_rank: Unknown
timestamp: November 10, 2021, 10:14:52 am
content: Dave looks at his TOP 5 (plus change) Jellybean OPAMP's, and explains why you need to know them.00:00 - Jellybean OPAMP's01:47 - LM35807:51 - FET Input TL071/72/7411:28 - CMOS LMV35815:17 - LM32417:23 - The LM321 is NOT a thing19:09 - Oh, all right, the LM74119:41 - RC455821:11 - The Audiophiles go WILD! The NE553222:06 - OP07 Precision OPAMP

author: T3sl4co1l
author_rank: Super Contributor
timestamp: November 10, 2021, 10:23:33 am
content: TLV2372 didn't make the list smhTim

author: Kleinstein
author_rank: Super Contributor
timestamp: November 10, 2021, 01:40:31 pm
content: The Ti datasheet for the TL07x is confusing. It includes the TL07x H series and these are totally different (CMOS) parts. It is still a good OP but a bloody cunfusing part numbering. Looks like the want to carry over the old part number and sell cheaper to make CMOS chips. They are good in some repects, but also worse than the old in other aspects. There are a few threads about this, e.g.:https://www.eevblog.com/forum/beginners/tl072-minimum-supply/msg3680230/#msg3680230The NE5534 is the single version, not the quad. Again a bit confusing numbering (like the LM2904 LM2902 for the dual and quad). The note with the need for external compensation is good however.The RC4558 is sometimes called equavalent to 741, but it is actually a quite differente OP: higher BW, lower noise,... more like half the way to the NE5532. Closer to an dual 741 is the MC1458 /1558. The RC4558 is still a good yellybeen part - wish there would be a single version (because of the lower power).The LM321 is a tricky one:often they are LM358 dies with just 1 half used. The current per OP is twice. AFAIK a few are actually single dies. SO unleess you really need a small case one could as well use the 358.There is another odd point: there was a seprate chip with LM321 part number and this was not a single OP.AFAIK there is no direct dual or even quad OP07. With the relatively high power consumption this would also no be practical. There are duals and quads from later improved versions - e.g. as my new favorite replacement OPA202 / OPA2202 / OPA4202. In the old days this was more like AD704,705/706.

author: ormaaj
author_rank: Contributor
timestamp: November 10, 2021, 02:40:58 pm
content: How did these end up being made by multiple manufacturers under the same model name? Does the mask mark expire and somehow another company either gets ahold of it or reverse engineers it from samples?Also how does it make economic sense to use masks from the 70s?? For maximum cheap, you should balance cheapest process technology with maximum parts per wafer and minimum out-of-tolerance yield loss. But each of these parts has a separate lineage of improved versions from each manufacturer. Those derivatives are unsurprisingly rarely made by more than one manufacturer. Surprisingly though, such parts rarely compete with the ancient originals on cost and somehow never manage to obsolete them. Was copying one another's model names just a trendy thing that went away by the 2000s?

author: T3sl4co1l
author_rank: Super Contributor
timestamp: November 10, 2021, 04:01:13 pm
content: I certainly don't have a complete history of multiple sourcing, but it's my understanding that, a lot of that was driven by direct military requirement. Keep in mind, silicon valley has always been closely integrated with the military-industrial complex; they are what enabled ever more advanced and compact missile guidance, RADAR, countermeasures, cryptography, etc. -- everything from bombs to bugs. So, it pays to have one spec (e.g. JEDEC 2Nxxxx series) and everyone makes parts that fit them. I don't know what the extent of systems like JEDEC really was/is, why they didn't put amplifiers in there for example (but some quite complex optos are, take 6N137 for example), but in any case, op-amps and comparators and everything else were certainly too important to pass up, plus everyone needed them for commercial purposes anyway, so why not make a copy and get your toe in the door?As for origin, I don't know if that was by licensing, copying (reverse engineering (RE)), or parallel development, and how much of each. Certainly if nothing else, some work was required to get one chip design working on another fab line, fabs were especially finicky back then (and, I would suppose, are only so much worse today -- they're just also better at abstracting it out via simulation and synthesis tools).One famous case I do know was by licensing: the only reason AMD has x86 to this day (well, to this day, who knows what else might've happened through history, right, but this is how it started anyway), is because the military insisted upon second sourcing the CPUs and so made Intel and AMD do a cross-licensing deal. That, or to address anticompetitive action? Now I can't remember... anyway, it's a well recorded part of computer history.(In contrast, Cyrix, or a couple of others I think, got the 486 by RE. So, more than just the two giants in that era of x86 history.)Tim

author: tszaboo
author_rank: Super Contributor
timestamp: November 10, 2021, 06:36:22 pm
content: I guessed right 5 of these on list before playing the video. What did I win?

author: Per Hansson
author_rank: Unknown
timestamp: November 10, 2021, 07:01:12 pm
content: Quote from: tszaboo on November 10, 2021, 06:36:22 pmA LM741

author: David Hess
author_rank: Super Contributor
timestamp: November 10, 2021, 07:55:59 pm
content: 1. The 741 obviously, although the 301A is practically the same part and more universal. There is little reason to use a 741, but the 301A has all of the same virtues and additional capabilities beyond most modern parts through its external compensation which allows clamping.2. The TL071/TL072/TL074 are the last survivors of the jelly bean JFET input parts. The National LF series JFETs were jelly bean parts in the past.3. The NE5532, or one of this variations.4. The OP-07 despite being completely obsoleted by improved parts. The virtue of the OP-07 is that it is widely second sourced making it the cheapest precision part.5. LM358/LM324 - These are dual and quad versions of the same part. The single version never became popular.Quote from: Kleinstein on November 10, 2021, 01:40:31 pmThe RC4558, like the RC4136, use a completely different topology than the 741. The 741 and 301 use cascaded NPN and PNP pairs to combine the performance of the NPN transistors with the high base-emitter breakdown voltage of the PNP transistors. The RC4558 and RC4136 use only the PNP differential pair. Besides the performance difference, the input bias current is reversed between the 741 and 4558. I am not sure if the RC4558 and RC4136 achieve small die size through transconductance reduction; the schematics do not show it but often it is left out, and the shown compensation capacitance is pretty high, although that could be marked wrong also.The 1458 is closer to a dual 741 because it uses the same NPN and PNP input stage arrangement, but the 1458 includes transconductance reduction so the internal compensation capacitor can be much smaller saving space and allowing room for a dual part. The LM348 quad 741 also uses transconductance reduction for the same reason.Quote from: Kleinstein on November 10, 2021, 01:40:31 pmThe OP-207 was a dual OP-07. If PMI made a quad OP-07, it should be in their last databook before Analog Devices bought them. I doubt a quad OP-07 was ever considered because how would offset null be brought out? The dual OP-207 was only available in a 14 pin package, and they even brought out separate power supply pins. It was probably a single die and not two OP-07 dies because of parameter matching.Linear Technology made a dual OP-07 in the form of their LT1002 which was functionally and pin compatible with the OP-207, so PMI was not the only one who saw a demand for such a part.Quote from: ormaaj on November 10, 2021, 02:40:58 pmReverse engineering was common, and then patents were either cross licensed or sometimes an implementation was made which avoided the patents. Sometimes even the same part from the same manufacturer is implemented later with a different layout.QuoteThese parts still require a 44 volt bipolar NPN process with lateral PNPs for level shifting and high base-emitter breakdown voltage, which means using the processing steps of an old process if the performance and functionality is to be comparable, and those old processes use a minimum number of mask steps making them less expensive.How much smaller is a "modern" 44 volt process compared to that? Parts like the 1458 and 348 were made much smaller on the same old process allowing dual and quads by using techniques like transconductance reduction.As far as I know, a modern 44 volt NPN process can be implemented with finer geometry, and I am sure this has been done for "modern" 44 volt precision parts, but that would have little benefit in area reduction of a 741 design with its large internal compensation capacitance.QuoteThose improved versions take just as much area to provide the same features so are not any cheaper. When I look through TI's parts, the only 741 replacements which are less expensive are parts which use less die area because of a smaller compensation capacitor allowed by transconductance reduction. The smaller "improved" 741 is the 1458.Note that one of the rare features of the 741 which is commonly not found in modern parts is wide differential input voltage range. This is difficult to duplicate on a "modern" high performance process, and parts built on a modern process with a differential input voltage range greater then about 7 volts are rare or non-existent. Offhand I cannot name any, and I have looked for them before.

author: Cerebus
author_rank: Super Contributor
timestamp: November 10, 2021, 08:06:48 pm
content: Quote from: tszaboo on November 10, 2021, 06:36:22 pmOnly third place I'm afraid, a no-expenses paid, 2 day, trip to Clacton-on-Sea (Second prize was 1 day, and 1st prize you don't have to go at all).

author: PartialDischarge
author_rank: Super Contributor
timestamp: November 10, 2021, 08:12:32 pm
content: I don't have any jellybean opamps, I just search by the required specs and select a # of possible parts for the project.In contrast to diodes or transistors, for which I have jellybean parts, opamps are so complex and have such a large # of specs that I prefer to do it this way.

author: David Hess
author_rank: Super Contributor
timestamp: November 10, 2021, 08:49:22 pm
content: Quote from: MasterTech on November 10, 2021, 08:12:32 pmSome operational amplifiers are "universal" in the sense of covering a wide range of applications. The 741 fits this because of its good performance and wide differential and common mode input range which made it "universal" compared to the previous parts it replaced. Later the 324/358 became universal for single supply applications.

author: rvalente
author_rank: Frequent Contributor
timestamp: November 10, 2021, 09:01:08 pm
content: Mates,Considering this jelly beam op amps in dual and quad versions for symmetric supply (+9V and -9V) which of them would have the lowest offset?

author: PartialDischarge
author_rank: Super Contributor
timestamp: November 10, 2021, 09:08:05 pm
content: Quote from: David Hess on November 10, 2021, 08:49:22 pmThe 741 is the opamp I learnt with and studied in college, what disqualifies it for me even in prototypes is the big size, I tend to use SOT23-5 or Soic-8. I don’t use breadboards, don’t even own one, only perfboards with thin soldered wires for the prototypes

author: rvalente
author_rank: Frequent Contributor
timestamp: November 10, 2021, 09:10:24 pm
content: Quote from: MasterTech on November 10, 2021, 09:08:05 pmI just do the same thing. 100mil perfboard, 0805 caps/resistors and enamel wire. Breadboards/protobards are terrible little devils

author: David Hess
author_rank: Super Contributor
timestamp: November 10, 2021, 09:14:46 pm
content: Quote from: rvalente on November 10, 2021, 09:01:08 pmThe only precision part listed is the OP-07.

author: Unixon
author_rank: Frequent Contributor
timestamp: November 10, 2021, 11:14:13 pm
content: Q1: What is a typical industry practice of coming up with a standard pinout across different manufacturers?Q2: Op amps that provide additional connections to internal nodes for tuning vs op amps that don't. Pros, cons, examples. Will an external circuit ever be better than on-die circuit considering part characteristic matching and temperature dependency of everything etc?

author: rvalente
author_rank: Frequent Contributor
timestamp: November 10, 2021, 11:24:46 pm
content: Generally single op amp follow tl741 pinou, dual lm358 pinout, quad lm324. Those with dual offset or shutdown have special pinouts.

author: rvalente
author_rank: Frequent Contributor
timestamp: November 10, 2021, 11:25:51 pm
content: Quote from: David Hess on November 10, 2021, 09:14:46 pm

author: cortex_m0
author_rank: Regular Contributor
timestamp: November 11, 2021, 04:54:46 am
content: Dave should have reached out to Texas Instruments for a sponsorship!I think this is a good list. A reminder that while an op-amp can be used as a comparator, but a comparator chip will often provide better results. The LM293/LM393 family is a jellybean in that group. Whoa, there's Texas Instruments againIf you need 1.8Vcc operation, MCP6L01/2/4 is my go-to. Designed to mirror the LMV324 specs IIRC. I'm not actually aware of an Op-Amp that has 1.8Vcc operation and second-sourcing.

author: David Hess
author_rank: Super Contributor
timestamp: November 11, 2021, 05:09:13 am
content: Quote from: Unixon on November 10, 2021, 11:14:13 pmIf you are big enough, then you get to decide the standard.QuoteExternal offset null capability always provides a boost in performance if used, and it provides an even larger boost in performance for precision parts because for them, it also corrects input offset voltage drift. External offset null can also be automated, and provides some unusual functionality in esoteric designs. For instance the 318 can be used as an output stage for a composite amplifier through its offset null pins with its inputs disabled. Another weird use is to inject a current into one external offset null pin to turn a precision operational amplifier into a precision temperature sensor.External compensation allows for tuning of dynamic performance which cannot easily be replicated in a part without it, but nothing modern supports it.

author: David Hess
author_rank: Super Contributor
timestamp: November 11, 2021, 05:35:22 am
content: Quote from: rvalente on November 10, 2021, 11:25:51 pmThe LT1013 and LT1014 are probably the closest to "jellybean" dual and quad precision parts because they have multiple sources now. These are precision alternatives designed by Linear Technology for the LM358 and LM324 single supply dual and quad jellybean parts.

author: Cerebus
author_rank: Super Contributor
timestamp: November 11, 2021, 11:48:44 am
content: Quote from: David Hess on November 11, 2021, 05:35:22 amNot exactly "jellybean" pricewise though - a reel of 2500 of the lowest grade of the TI second sourced ones will still set you you back £1 each, they're more like £2 each in small quantities. Still a good part for the money, in particular the long term drift in input offset voltage is better than you'll find on many much more expensive precision OPAs.

author: rvalente
author_rank: Frequent Contributor
timestamp: November 11, 2021, 01:00:59 pm
content: Quote from: Cerebus on November 11, 2021, 11:48:44 amGreat tip, this is what I was looking for, tks mate

author: tszaboo
author_rank: Super Contributor
timestamp: November 11, 2021, 01:26:45 pm
content: Quote from: David Hess on November 10, 2021, 08:49:22 pmYes, they are very good for a lot of applications. Unfortunately, there aren't many low power opamps which would be jelly bean. I mean less than 10uA, but rather 1uA Iq. The other part that I would really like to see is shunt reference, that would work with just 1uA current. I have 1-2 parts that do this, but they are relatively expensive, and no second source.

author: nctnico
author_rank: Super Contributor
timestamp: November 11, 2021, 02:03:47 pm
content: Quote from: MasterTech on November 10, 2021, 08:12:32 pmSame here. I have a whole bunch of opamps in my component database but it happens regulary that I add a different/new opamp to it due to the requirements of the circuit which doesn't fit an opamp I have used before.

author: Peabody
author_rank: Super Contributor
timestamp: November 11, 2021, 04:14:36 pm
content: I selected the MCP6041 opamp for use as a comparator in a lithium battery solar charger:https://ww1.microchip.com/downloads/en/DeviceDoc/20001669e.pdfI didn't find a comparable comparator on Digikey with a push/pull output with the same features - vanishingly small operating current (1uA or less), common mode input range extending to slightly above the upper rail, relatively cheap (although not in the jellybean class). Does anyone know of such a comparator? And in any case, the opamp is only driving a mosfet gate to let the battery power the load, or not, so switching speed isn't important. I keep seeing that you should use a comparator when you're doing the comparator function, not an opamp, but in this case I don't see why. The opamp seems to work fine. I would only like it to work at higher than 6V if possible. The circuit is shown below.

author: Kleinstein
author_rank: Super Contributor
timestamp: November 11, 2021, 04:22:15 pm
content: There is the MCP6541 - like the 1:1 comparator counterpart to the MCP6041 OP.The reason to prefer a comparator is to get a faster rise / fall time at the output. The comparator is kind of missing the compensation cap and is thus faster, like a higher BW part at the same power level.Some modern comparators have a little hystereseis. This can be good, but can also be bad.

author: Peabody
author_rank: Super Contributor
timestamp: November 11, 2021, 04:33:52 pm
content: Thanks very much. Unfortunately, that comparator's maximum operating voltage is 5.5V versus 6V for the opamp version. I think that's a deal killer for 5V panels, but will look at it. The hysteresis thing I will have to think about. With the opamp, when the source is lower than the drain, the opamp output goes low to turn on the mosfet, but even with the mosfet fully on, the output stays low, which is what's needed. I think it stays low because of the voltage drop caused by RDSon. I would need to think about how the hysteresis would affect that.

author: Cervisia
author_rank: Regular Contributor
timestamp: November 11, 2021, 07:41:00 pm
content: Quote from: cortex_m0 on November 11, 2021, 04:54:46 amMCP6001/TLV6001

author: Kleinstein
author_rank: Super Contributor
timestamp: November 11, 2021, 08:28:29 pm
content: The old LM10 was available from LT too, and it worked from 1.1 V on. It's an old one and rather extreme in the supply range as it can also work with 40 V supply.There are quite a few CMOS OPs with relatively similar properties from many manufacturers. Not the same part number, but similar performence is available. The MCP600x series is kind of similar to the LMV358 in many aspects and also very popular.

author: Unixon
author_rank: Frequent Contributor
timestamp: November 11, 2021, 09:25:04 pm
content: Quote from: David Hess on November 11, 2021, 05:09:13 amNowadays many manufacturers are equally big enough, yet packages and pinouts somehow converge.Some other parts look like they were intentionally made incompatible without a good reason.It would be great to hear from the engineers who designed this stuff when how and why particular decisions were made.Quote from: David Hess on November 11, 2021, 05:09:13 amCould you suggest a good reading on this topic? I.e. what is exactly wrong with non-compensated parts and what characteristics are modified in what way with what external circuits.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: November 11, 2021, 10:06:18 pm
content: Basically, external comp allows performance comparable to current-mode op-amps (which have high BW fairly independent of gain), while keeping the ease of use of the voltage-mode op-amp -- save for the sole exception of an additional required compensation network (typically C or R+C from the internal gain node to GND, or between two pins).When it's the internal gain node, having that exposed also opens up opportunities like joining multiple amps together to make precision limiters.But, it seems history was against that, and so we all got fixed-compensation (largely unity-gain stable) op-amps, consequently with terrible GBW-power tradeoff when high gain is required.It's not like it's that much harder to use, it's literally one or two added components per amp. Maybe a bit annoying for duals or quads; no one ever made a 10 or 12-pin DIP so you'd have duals in DIP14 at least, and so on. (Though if we're talking hypothetical alternate histories, maybe DIP10 would've caught on then, who knows.) Probably impractical as bandwidth goes up -- the physical size of the gain node begins to matter, and taking it out to a whole massive pin starts to cost a lot of performance, plus making the device more susceptible to ambient noise, or stray feedback paths. Today we have unity-gain compensated voltage-mode op-amps with GBW in the GHz, where this is absolutely a relevant factor; but back in the days of 10-100MHz GBW being fast, it wouldn't have been such an issue (and indeed, wasn't, for the devices that did function this way)."Unity gain stable" is an important term here. It means that, given the amp's dominant 90° phase shift (it looks like an integrator -- which is also to say, it's dominant-pole compensated), gain falls less than 1, at a frequency lower than additional poles, which add phase shift that would then cause it to oscillate.If the phase margin were measured at gain = 10 instead, we could accept having poles above that point (i.e., in the 1 < gain < 10 range of frequencies) and still have stable operation, but we'd have to sacrifice that we can't reduce gain below 10, i.e. we definitely can't make voltage followers for example (at least, not without hackery -- we can increase noise gain, because this is actually the figure relevant to stability; but as the name suggests, then noise goes up, and this might be worse overall). Such devices are indeed available, for example some LT families have unity, 5 and 10 gain stable parts, so you can get the extra bandwidth when you also need the gain. But, LT parts being what they are, and non-unity-gain-stable in general -- they're less common, and more expensive.I should probably explain poles as well. Taking the transfer function of the amp, in the frequency domain, H(ω) = Vout(ω) / Vin(ω), we find a normally very high (but finite) gain at DC, then at a low cutoff frequency (typically 10Hz, give or take a few decades), it changes to dropping proportionally with frequency (-20dB/dec, integrator characteristic) (this is the dominant pole). Then at, somewhere past GBW presumably, it drops more (-40dB or faster). Each transition, from flat to -20, or -20 to -40, etc., has a characteristic frequency. These are the intersection points of the asymptotes on the Bode plot (give or take). When we write out (or solve for an approximation of) the rational polynomial corresponding to this transfer function, the zeroes of the denominator polynomial arepolesof the transfer function. The poles have units of frequency (the transfer function is in the frequency domain), that being the "break frequency" where a new asymptote takes over in the Bode plot.So, it's actually rather abstract, to do with how we model a system as lumped equivalent elements (a passive RLC circuit has a corresponding rational polynomial describing its frequency response), and how we calculate it (polynomials), but at its most basic: a pole is a cutoff frequency.(And, zeroes of the numerator of the transfer function, are also zeroes of the whole thing. So, sometimes we have those, which has advantages, as when the phase shift balances out that from poles, extending phase margin (pole-zero cancellation, or lead-lag compensation); but also having consequences for stability in a feedback loop, particularly for RHP (right half-plane) zeroes, which can be inverted in a feedback loop, becoming poles, and RHP poles mean oscillation.)(Oh, and in general, poles/zeroes have complex values, so we plot them on the complex plane. A pole p = ξ + jω with positive real value ξ > 0, means the response will grow over time, i.e. diverge, i.e., is unstable or oscillating. So a "RHP" pole is generally a sign that something has gone wrong. Finally, when we plot a transfer function, we plot along the imaginary axis, s = jω = j 2 pi f.)Tim

author: David Hess
author_rank: Super Contributor
timestamp: November 11, 2021, 11:18:56 pm
content: Quote from: Unixon on November 11, 2021, 09:25:04 pmThere were at least 2 standards for placement of offset null and compensation pins, and multiple ways they worked. Some offset null pins use an adjustment to the positive supply, and some use an adjustment to the negative supply.Some parts have an alternative pinout because the die has to be rotated 90 degrees to fit inside a smaller package. Check out the SO-8 packaged LT1013/LT1078/LT1178 for an example of this. Later parts fixed this by either using a better layout or a smaller IC die, which points out that analog ICs *have* decreased in size with more advanced processes.QuoteCompensated parts have the advantage of being easier to use, but do not provide the same level of dynamic performance in a variety of circuits. Non-compensated parts are theoretically cheaper because of the area saved by not integrating compensation capacitance, and they have performance and functional advantages if the designer chooses to take advantage of them.The use of non-compensated parts is largely irrelevant today because the only common non-compensated parts are the LM301A and LM308/LT1008. Linear Technology has a few parts which support "overcompensation" but that is not the same thing.Check out datasheets for the LM301A, LM308, and LT1008 for discussions of operational amplifier external compensation.National application note 29 discusses the LM308 in general and its compensation.National linear brief 2 discusses LM301A feedforward compensation.National linear brief 4 discusses LM301A fast compensation.National linear brief 14 discusses LM308 feedforward compensation.Chapter 10 of theAnalog Devices Amplifier Applications Guide (1992)discusses how to abuse the compensation and offset null pins.

author: David Hess
author_rank: Super Contributor
timestamp: November 11, 2021, 11:49:31 pm
content: Quote from: tszaboo on November 11, 2021, 01:26:45 pmNo micropower parts were ever popular enough to reach jellybean status. In the past there were some "programmable" operational amplifiers which allowed adjusting their operating current down to micropower levels, and some of these are still available. Modern micropower parts, including references, are readily available, but none reached jellybean status and they come at a price premium.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: November 12, 2021, 01:44:11 am
content: LM13700 being the last, more or less; not so much a programmable amp (there's more proper examples of that), as, its transconductance is proportional to Iabc, so it can be used for variable gain, variable resistor, tunable filter, etc. applications, as well as low current apps.Tim

author: Unixon
author_rank: Frequent Contributor
timestamp: November 12, 2021, 10:17:18 am
content: Quote from: David Hess on November 11, 2021, 11:18:56 pmThanks. I briefly read through suggested sources and began wondering why the word 'compensation' has been adopted to describe these performance modifications.In my understanding 'compensation' means that a part is below its normal requirements and has to be modified to become normal, however, in practice this word is used to describe clearly augmentations of a part that is already normal and satisfies its declared properties into a circuit with advanced characteristics. So it is a compensation/augmentation against target performance in application and not against declared baseline performance. Well, OK, but I still think this is weird.

author: GreggD
author_rank: Regular Contributor
timestamp: November 12, 2021, 12:35:49 pm
content: Yah, "and yes you can get it in a single version of the LM324, the LM321"Well no you can't.No stock.I did get some from LCSC along with Some LMV321.And don't trust Octopart pricing of LCSC parts. Check LCSC to get accurate prices.

author: Cerebus
author_rank: Super Contributor
timestamp: November 12, 2021, 01:12:12 pm
content: Quote from: Unixon on November 12, 2021, 10:17:18 amIt's worth understanding that in this context 'compensation' is shorthand for 'frequency compensation'. That contraction is used so often that people sometimes forget to add the 'frequency' part when they are writing for instructional reasons, which can make things a bit difficult if you're not already familiar with the territory. So in all the above for 'compensation' read'frequency compensation', 'compensated' read 'frequency compensated' and so on.We'recompensatingfor the non-idealfrequency response of apracticalconcrete actual operational amplifier implementation versus anidealtheoretical operational amplifier. Theidealtheoretical operational amplifier hasinfinite bandwidth, infinite gain, infinite input impedance, zero output impedance, and zero delay.

author: ledtester
author_rank: Super Contributor
timestamp: November 12, 2021, 01:57:08 pm
content: I don't remember the exact part numbers, but I've seen CA3xxx op-amps in a lot of circuit designs. Would they also be considered a jelly-bean op-amps?

author: Kleinstein
author_rank: Super Contributor
timestamp: November 12, 2021, 02:22:16 pm
content: The CA3140 and similar were early CMOS OPs. At there time they were quite common, but not sure if there was a 2nd source. by now they are quite expensive and more a part for old circuits, nothing I would really use for a new circuit.Slightly more yellybean are the TLC271-4 (TS27x from ST) CMOS OPs for up to 16 V supply.

author: T3sl4co1l
author_rank: Super Contributor
timestamp: November 12, 2021, 03:17:13 pm
content: As I recall, there's a couple CA3xxx that are still relatively fast and cheap, RRIO or single supply, and high voltage (as in suitable for 12V supplies). Wouldn't say jellybean, but nice to have.ST has a number of very cheap amps, roughly like LM358 with improved specs; but still just a bit janky I think, or at least that's the impression I get.Or particularly at low voltages, there's a whole slew of MCP6Lxx and the like, that have excellent specs, including precision (chopper/autozero), speed, RRIO, etc. Not exactly jellybean prices though.Like, compare these with the TLV2372 I mentioned earlier -- it's high voltage (16V), average specs (like a LM358), RRIO, well behaved. Not especially cheap, but good enough to use. I consider it a jellybean, so there's some YMMV as to what someone considers to be that. Most generally, a jellybean ought to be multiple source, very cheap, and probably old; which the video examples cover, and these ones not so much. As for in-house cases or personal opinions, some of those conditions may be bent or excepted for various reasons. (Like, personally, I just like an RRIO part that I don't have to think about and Just Works.)Tim

author: Unixon
author_rank: Frequent Contributor
timestamp: November 12, 2021, 03:30:36 pm
content: Quote from: Cerebus on November 12, 2021, 01:12:12 pmWell, I understand this, but I still find confusing the following.An op amp that is not dead has non-zero frequency response and hence it could be said that it is already partially compensated up to some level.Op amps with internal compensation do only their characteristic response optimized for something, let it be unity gain stability or any other mode of operation.Op amps with pins to add external compensation circuit should be already half-compensated for some non-zero response and then we modify that response even further with an external circuit.Are these op amps capable of stable operation without any additional components or are they inherently unstable without external compensation circuit?Many old op amps have these internal nodes exposed, I have a number of them in storage but always hesitated to do any projects with them, probably because I'm a bit lazy for doing proper analysis for these weird bastards.

author: Cerebus
author_rank: Super Contributor
timestamp: November 12, 2021, 03:36:13 pm
content: Quote from: Unixon on November 12, 2021, 03:30:36 pmIt's different on a case by case basis, some are, some aren't, some are until you put more thanxnF of capacitance on the output. Hence: "Alwaysreadthe data sheet".

author: Unixon
author_rank: Frequent Contributor
timestamp: November 12, 2021, 03:37:15 pm
content: Quote from: Kleinstein on November 12, 2021, 02:22:16 pmAFAIR, CA3140 is a cool op amp for building sensors, it's not cheap but also not prohibitively expensive.I wouldn't call this one jellybean, it's rather on the top of a little mountain.

author: Unixon
author_rank: Frequent Contributor
timestamp: November 12, 2021, 03:43:10 pm
content: Quote from: T3sl4co1l on November 10, 2021, 10:23:33 amBecause there's only a list of 5, and this goes by number 6.L272 is expected be in first 10 for its inexpensive 500mA outputs.

author: MathWizard
author_rank: Super Contributor
timestamp: November 13, 2021, 12:01:59 am
content: Wow I thought the LM4558 as an audio op-amp, was a bit more special than just a dual 741, but I'm just getting to the point where I pay more attention to op-amp datasheets anyways.I even have ne5532 or whatever, but still used 4558 in my computer stereo repair

author: David Hess
author_rank: Super Contributor
timestamp: November 13, 2021, 01:34:27 am
content: Quote from: GreggD on November 12, 2021, 12:35:49 pmIn the past there were several "single" 324/358 parts from different manufacturers, but none of them remained in production. Linear Technology has a single version (LT1006) of their improved 324/358 (LT1013/LT1014), and a single (LT1077) of their micropower improved 324/358 (LT1078/LT1079). They are incredibly useful but relatively high cost.Quote from: Unixon on November 12, 2021, 03:30:36 pmThey are almost always completely uncompensated. Offhand I do not remember any exceptions but I am sure there are some weird parts.QuoteAbove some high closed loop gain, they do not require any extra compensation. For gains lower than this, external compensation must be applied which usually comes down to adding a single small capacitor.There are some operational amplifiers with "overcompensation" terminals which are unity gain stable with no external parts, but additional compensation may be added to reduce noise and increase phase margin so more difficult loads can be driven.Quote from: MathWizard on November 13, 2021, 12:01:59 amThe 741 does not quite have the full power bandwidth to support audio, but the 4558 does, so by default it became seen as an audio amplifier even though the original datasheet says nothing about audio applications, unlike parts like the LM833 which were intended for audio.Quote from: T3sl4co1l on November 12, 2021, 01:44:11 amI was referring to "programmable" operational amplifier like the Fairchild uA776 which is essentially a 741 with variable supply current from 1 to 400 microamps allowing a 20 kHz to 1 MHz gain-bandwidth product, 0.01 to 1 V/us slew rate, and 0.2 to 30 nanoamp input bias current. I think every major manufacturer had their own equivalent to something like this. Later PMI had the OP-22, and Linear Technology had a couple which should still be available.

author: Kleinstein
author_rank: Super Contributor
timestamp: November 13, 2021, 08:21:32 am
content: The NE5534 is an OP with compensation for higher gain and the option to add more to make it unity gain stable. For some reason the DS I have found is not specific about the gain needed to get away without an extra cap. Looks like 2 or 3 may do.For an OP with programmable biasing, there is the TLC271 as a relatively common type. There are / were older ones in the ICL76xx series (Intersil+Maxim), but these got crazy expensive by now. 20 years one could have nearly considered them yellybean.A slighlty improved (slightly faster and less coss over distortion - so more audio than precision like the LT1013) single LM358 similar OP is the MC33171. Not as cheap as the original LM358 and still at a moderate price.

author: Fungus
author_rank: Super Contributor
timestamp: November 14, 2021, 10:16:17 am
content: Would be interesting to see a side by side performance test of aliexpress specials vs. "real" parts for these opamps.(or at least the LM358 ("basic"), LMV358 ("R2R") and NE5532 ("audiophile") opamps)

author: robballantyne
author_rank: Newbie
timestamp: November 14, 2021, 11:39:42 pm
content: I've been making my way through the analog chapters of "Learning the Art of Electronics" (https://www.amazon.ca/Learning-Art-Electronics-Hands-Course/dp/0521177235/ref=sr_1_1?keywords=Learning+the+Art+of+Electronics&qid=1636932923&sr=8-1). It uses LF411s for most of the Op Amp hands on labs. I would have thought this "made the grade" as a Jelly Bean. It's slightly better than the LM358 in most ways but way better in terms of input current due to JFET inputs. It's also pretty available on DigiKey. It appears to be around 4x the cost of the 358. I'm just curious if it would be jelly bean but perhaps just not Top 5.Thanks,R

author: T3sl4co1l
author_rank: Super Contributor
timestamp: November 15, 2021, 01:01:02 am
content: It's certainly among the JFET jellybeans. LF353, TL072 and a few others share a similar status.Tim

author: David Hess
author_rank: Super Contributor
timestamp: November 25, 2021, 07:52:25 pm
content: I just made a connection with an obscure piece of jellybean operational amplifier history - George Erdi.I knew that George Erdi had designed the OP-07 while at PMI, and was the uncredited designer (1) of the Fairchild 725 which was the first precision integrated operational amplifier:http://analogfootsteps.blogspot.com/2014/02/guru-3-george-erdi.htmlBut he also designed the LT1006(single)/LT1013(dual)/LT1014(quad) while at Linear Technology which are an improved 358(dual)/324(quad) with precision and a class-AB output stage. Where have I run across that before?Fairchild also had a 358(dual)/324(quad) design improved with a class-AB output stage in the form of the 799(single)/798(dual)/3403(quad), (2) so I wonder if George Erdi was involved with those.Does anybody know why the 324/358 design has a class-b output stage instead of class-ab?(1) I do not know if anybody else has noticed, but Fairchild, National, and Texas Instruments made it policy not to credit engineers with their publications, while the companies started by dissident engineers from these companies like Analog Devices and Linear Technology did. PMI did not either but George Erdi also moved from PMI to Linear Technology.(2) The datasheets for these parts explicitly say the output operates down to the negative supply, but oddly enough the schematics (and specifications) show no such capability. I wonder if that was left out of the schematics to foil competitors. Maybe they never worked or were never finished.

author: Cerebus
author_rank: Super Contributor
timestamp: November 25, 2021, 10:30:34 pm
content: George Erdi was also a regular contributor to academic publications, so unlike his peers - who tended to publish mostly in the trade press or their employer's application notes - you tend to be able to find neutral information from him (i.e. designed to serve the purpose of communicating the technique rather than with the tacit understanding that the publication was to serve an employer's interests).I've found papers of his in the IEEE Journal of Solid-state Circuits and in IEEE conference proceedings.

author: David Hess
author_rank: Super Contributor
timestamp: November 25, 2021, 11:04:52 pm
content: Quote from: Cerebus on November 25, 2021, 10:30:34 pmI brought it up because it makes makes me wonder how much motivation that policy added to these critical employees leaving, and eventually forming their own company where their work would be more widely recognized.

author: mawyatt
author_rank: Super Contributor
timestamp: November 26, 2021, 02:14:45 am
content: George Erdi's designs were extraordinary, in the same class as Widlar's IMO. Think George invented the cross-coupled quad diff amp, and his input bias current canceling scheme was one of the best analog designs I'd ever come across.Agree, he deserved way more credit, same goes for Oliver Heaviside.Best,

author: David Hess
author_rank: Super Contributor
timestamp: November 26, 2021, 02:12:33 pm
content: Quote from: mawyatt on November 26, 2021, 02:14:45 amAre you referring to the thermally coupled cross-quad, like in the 725 and all later precision parts, or the linearized cross-quad?

author: mawyatt
author_rank: Super Contributor
timestamp: November 26, 2021, 02:22:42 pm
content: Quote from: David Hess on November 26, 2021, 02:12:33 pmYes, the thermally cross coupled quad used in the 725.Best,

author: David Hess
author_rank: Super Contributor
timestamp: November 26, 2021, 03:03:36 pm
content: Quote from: mawyatt on November 26, 2021, 02:22:42 pmI asked because the first time I ran across the linearized cross-quad was in a PMI application note 105, and George Erdi worked there so might have invented it also.

author: Rich S
author_rank: Newbie
timestamp: November 26, 2021, 11:51:15 pm
content: Picking the top 5 jellybean op-amps is like picking the top 5 cars. The product has diversified into so many categories, most are specialized in some ways.Horowitz & Hill did alotof work: their Art Of Electronics has many tables of their chosen favorites. As mentioned the LF411 is their preferred "teaching tool" op-amp. AoE 3rd ed., table 4.2a, is the starting place for choosing op-amps -- over 30 parts there alone. (Note: their focus is on extant parts, & not historically what has been 'popular'. So they omit the LM741. And only some of these are 'jellybeans'). Top of list, no surprise, is the LM358/LM324 - it just delivers a high bang-for-buck.While mentioning the designers behind the op-amp winners, Like George Erdi, let's mention Tom Fredericksen. He designed the quad amps LM3900, LM324, and LM339. I don't know if he designed these quads first,thenthe dual/singles; or, someone else did those & he did the quads.

author: Cerebus
author_rank: Super Contributor
timestamp: November 27, 2021, 12:49:16 am
content: Quote from: Rich S on November 26, 2021, 11:51:15 pmNo it's not, it's like picking the top fiveeconomycars. Jellybean remember, as in"inexpensive enough that you don't bother about the price of a single one, just the price of bowlfuls of them". Sospecialiseddoesn't come into it, jellybean op amps are, by their very nature, generalists. Youcando the weekly shop in a Ferrari, just as youcanuse an OPA627 to build a low bandwidth, gain of 1, buffer - but in practice neither are in the running for everyday humdrum applications.

author: David Hess
author_rank: Super Contributor
timestamp: November 27, 2021, 05:51:50 am
content: Quote from: Rich S on November 26, 2021, 11:51:15 pmNational had a whole series of LF numbered JFET parts, and I prefer them to the Texas Instruments TL series, but they are less available now so more difficult to recommend. They are or were second sourced however, and Linear Technology made improved replacements for many of them.

author: Kleinstein
author_rank: Super Contributor
timestamp: November 27, 2021, 08:59:32 am
content: The difference between LF411, LF351 and TL071 is rather small and for many uses it does not matter. Today the TL parts have the best availability. It is rare that a circuit defigned with the LF411 in mind would not work with one of the other variants.With many of the yellybean parts there are also similar parts that could also get a comparable price point - the exact part name usually does not matter. The yellybean parts also come sometimes with slightly different names like CA324, KA324, BA324 and so on.The yellybean parts often stand for a class of chips and there are sometimes similar parts that are not all the way identical. This is especially the case with the NE5532 and LMV321 with similar (but not all the way identical) alternatives (e.g. LM833, MC33078, MCP600x).

author: mawyatt
author_rank: Super Contributor
timestamp: November 27, 2021, 02:07:52 pm
content: Quote from: David Hess on November 27, 2021, 05:51:50 amRecall some of those early National JFET LF type Op-Amps had a nasty feature where the output would invert when the input was significantly overdriven, not a good choice for feedback systems!Best,

author: Rich S
author_rank: Newbie
timestamp: November 27, 2021, 09:02:18 pm
content: Re "Jellybean remember, as in "inexpensive enough that you don't bother about the price of a single one, just the price of bowlfuls of them""Oh, I'm not sure the meaning is purely that.But OK, if low price is the main criteria, then, the new contenders are...(I did a quick look at Digi-key & Mouser; price in USD, thru-hole packages only)...the '358 is at #4. still competitive.#VendorMfr Part NumberPricingNumber of Channelsprice per chan.1MouserNJM2059D$0.384$0.092DigikeyMCP6004-I/P$0.574$0.143MouserNJM13404D$0.342$0.174MouserAS358P-E1$0.362$0.185DigikeyNJM2747D$0.764$0.196DigikeyAD8534AN$0.784$0.207DigikeyMCP6002-I/P$0.422$0.218DigikeyTLV2765IN$0.844$0.219DigikeyTLV2634IN$0.874$0.2210DigikeyTLV2635IN$0.974$0.2411MouserNJM12904D$0.492$0.25

author: David Hess
author_rank: Super Contributor
timestamp: November 28, 2021, 07:49:09 pm
content: Quote from: mawyatt on November 27, 2021, 02:07:52 pmThat is called phase reversal and it is a common flaw with BiFET operational amplifiers, including the TL series form Texas Instruments, (1) and some bipolar ones like the 324/358 and related devices. Analog Devicespublished detailson exactly what is going on.Modern improved parts (with different part numbers) may be designed to prevent or be resistant to phase reversal, like the Linear Technology LT1013/LT1014 and various LT BiFET parts.(1) From Texas Instrument TL071 datasheet -Avoid input voltage values below 1 V to prevent phase reversal where output goes high.

author: magic
author_rank: Super Contributor
timestamp: December 06, 2021, 01:32:08 pm
content: This paper about phase reversal is highly unhelpful as it deals with only one peculiar input stage configuration and recommends a fix (series resistance) which AFAIK does absolutely nothing to solve phase reversal in TL072 and similar chips.The problem with TL072 is simple: low common mode input voltage slides the input pair's operating point so low that it no longer is able to drive the (inverting) second stage so the output is pulled up by the second stage active load. And there are other chip with the same problem:- RC4558/4560/etc - identical topology with PNP instead of PJFET inputs, unlike µA741 which has no phase reversal- LM4562- a modern audio opamp, possibly similar to the above- LM324/358 - uses PNP emitter followers which permit input down to ground but not much below- TLC272/TS272 - the output doesn't really go up but its ability to sink current is compromisedA useful feature of TL072 and TI's CMOS TL072H is input range which includes the positive rail. One could say that they are "negative" single supply opamps.Somebody asked about internal compensation of NE5534. Every datasheet, even TI, says this in the second paragraph:QuoteAs an aside, I'm yet to find a specimen which is unstable at unity gain driving 10kΩ resistive load. I tried Philips, Signetics, JRC, TI.

author: David Hess
author_rank: Super Contributor
timestamp: December 06, 2021, 09:17:27 pm
content: Quote from: magic on December 06, 2021, 01:32:08 pmThe ancient LM301A also has a common mode input range which includes the positive supply.I have often wished that there was positive ground version of the 324/358 with NPN inputs instead of PNP inputs.

author: jwet
author_rank: Frequent Contributor
timestamp: March 28, 2022, 03:42:44 pm
content: I've enjoyed your series on Jelly Bean parts. I worked at Maxim as a new product definer and eventually worked my way up to managing all product definition for the standard products side of the company- this included amps, refs, switches, interface, non portable power, supervisors, comparators. I later worked as an exec on business development for new markets- automotive and industrial automation.Ironically in Maxim's story, these standard products were the real money making parts for the company- the margins were very good and the need was consistent. The black eye that Maxim got in the early 90's for poor delivery performance was caused mostly by new very high volume parts that only a few customer bought. At any given time, we had some surprise upside on some part. A lot of this was specialized power solutions for Notebook PC's and high efficiency high current bucks with VID control for the then new Pentium. The market has a long memory for this, I still see people bashing Maxim over a delivery issue that happened 30 years ago. Maxim ran all their own somewhat boutique fabs and trying to pump out a million parts a week of some exotic part that hadn't reach good yields can make your manufacturing pretty difficult. I have to respect them for never backing down on quality and we eventually caught up with demand- in fact Maxim was the first analog company to fab 300 mm wafers- that's the big fix.Back to Jelly beans. One of the strategies (among many others) were to look at good jelly bean parts and expand out from them in one of more vectors without affecting price too much. LTC did similar things. Maxim's specialty was CMOS analog though all of our processes could be called BiCMOS with really good CMOS analog, fancy precision resistors and good caps. LTC in contrast worked on mostly bipolar processes with some CMOS and included all the other goodies like SiChrome R's and poly caps.We developed a lot of neat strategies for new products. Most were market driven by customers telling us what they wanted and us extrapolating a bit on what they were really saying. We also did continuous studies of markets and product segments to see where there were wholes. Maxim couldn't (or shouldn't) compete with National making LM324's- we couldn't do anything with a part like that except make it cost more and it wouldn't use our strength. One of the strategies that was ongoing in the product oriented organization and business management side was to look at comps often jelly beans and see what could be improved to capture some of that market using our strengths.In Op-Amps specifically, this was pretty easy because the pinout of quads and duals were well established. If you take an LM358 dual as the center of gravity- you could push bandwidth, precision, low power, common mode range and output drive. If you look at Maxim's portfolio thought the 90's, you can see this taking place. We pushed power and voltage so low that no one cared anymore- we had several parts that drew fractions of a microamp! and people bought them. We made parts that could drive 80 mA of output, customers started using them as headset amps and little motor drivers this lead to a new product areas. We made a standard dual that could do 28 Mhz on 1mA of Icc- LM324 territory- there was a lot of pent up demand and led us in that direction to a line of high speed low power parts. Our rail to rail input parts led to high side current sensing apps which became an important product segment as everything was "portabilized". Most of these parts sold (not all) but they gave us a lot of intelligence of what the market really wanted. There was some misunderstanding in the market and inside our own managment that we were just carpet bombing the world- the truth was more strategic.I'll give you one more example war story as this is getting long. Analog switches existed mainly as the DG series from Siiiconix and AD. Originally JFET and later CMOS versions- the only customers were precision instrument guys, ATE and military. National created several jelly bean switches and muxes in the 4000 series- 4016, 4066, 405x series. (The 4016 was terrible and was soon replaced by the 4066.) Making useable analog switches on commodity CMOS process was genius and really opened things up. Maxim was making DG parts and improved second sources in those pinouts but we really hit something big when we started making good switches in the 4000 series pinouts. The vectors that you can push on with switches is on resistance, off leakage, capacitance, charge injection and HF isolation and cross talk. One of the more subtle parameters of switches is Ron flatness- this is the variation in resistance over the voltage range. Flatness turns directly into distortion- if you lower Ron and improve flatness, you can even drive low impedance loads with low distortion. We pushed on resistance down really low to fractions of an ohm- customers started using them to switch speaker and headphone circuits rather than using a second amplifier. This created a huge opportunity in cell phone as customers wanted to do things like use the main speaker as the ringer source but allow you to use headphones too- they couldn't use a simple swtiched source headphone jack. This jelly bean stuff cuts in a lot of directions and its really fascinating.I think every engineer should know these jelly bean parts and they should be the first thing they go to in a design. Only when they prove to themselves that a jelly bean won't do the job should they use something "better". They and their company will ultimately be more successful and have a lot less headaches.Once again a thought provoking and well presented topic.