Assortment of opamps - Page 1
Forum section: electronics / projects

author: pitagoras
author_rank: Regular Contributor
timestamp: May 15, 2017, 10:26:11 pm
content: I'm not really experienced enough to make a list of 10 opamps and I don't know the "modern" ones.Here (Argentina), it looks like I never find in local stores what I need for my experiments.For example, almost all LT and AD nice things are missing here.Lately I missed having things like AD711, AD706, LM7171, OP27, LTC1050.So I would like to import (from farnell or mouser...) a small stock of OPAMPS/comparators, not the "common" ones, rather special ones... which can come handy in different context.I know this is an ample question so let's say I will focus on precisión/measurement and building some test bench stuff.Thanks for your opinions.

author: james_s
author_rank: Super Contributor
timestamp: May 15, 2017, 11:59:21 pm
content: What are you wanting to do with them?I like the TL081/TL082 for general purpose use.

author: technix
author_rank: Super Contributor
timestamp: May 16, 2017, 12:21:01 am
content: So what op amps do you want?* General purpose: TL081/TL082/TL084* Rail-to-rail I/O, low voltage: TLC2272/TLC2274* Audio: TL071/TL072/TL074, NJM4558/NJM4559, OPA134/OPA2134/OPA4134* Percision: OP07C, OP1177/OP2177In my own projects I have pretty much deprecated LM324/LM358 entirely and substituted TL082/TL084 or TLC2272/TLC2274 entirely.

author: pitagoras
author_rank: Regular Contributor
timestamp: May 16, 2017, 12:23:38 am
content: Thank you for your answerQuote from: james_s on May 15, 2017, 11:59:21 pmThings like sigma/delta ADCs, analog front ends for measurement instruments, etc. Those are the things I'll be doing in the near future.Quote from: james_s on May 15, 2017, 11:59:21 pmYes I have some of those. "Common" stuff is easily available here.But for most applications I'd like to experiment these days, they are either too slow, of drift too much, or offset too much, or are not linear enough, etc.So the plan is to have a box of say 2 or 3 each of some 10 (?)

author: pitagoras
author_rank: Regular Contributor
timestamp: May 16, 2017, 12:25:55 am
content: Maybe my question should have been: what do you enjoy doing and what opamps do you have in your stock

author: RandallMcRee
author_rank: Frequent Contributor
timestamp: May 16, 2017, 12:35:02 am
content: ADA4522LT1097LT1028but I would look at your ADC datasheets first and foremost to see the type and family that are recommended. A lot depends on the SAR bandwidth. Also whether or not you need differential amps.

author: f5r5e5d
author_rank: Frequent Contributor
timestamp: May 16, 2017, 12:37:58 am
content: better performing recent op amps are generally only offered in smt, some only in packages smaller than soic-8most outstanding in a particular set of parameter SOTA op amps will be several US$ ea or more

author: BrianHG
author_rank: Super Contributor
timestamp: May 16, 2017, 12:55:00 am
content: For slow precision, OP07, for faster version OP27, for even faster version OP37....I've use OP37s and OP27s to drive power darlingtons, 1 OP37 to pre-amp gain, 4 OP27 as regulated followers buffers driving each base of the power transistors, to make a balanced output audio amp just missing the 100watt RMS point. It actually worked really-really-really well as I biased it nice and hot idling at 50 watts. Sounded like a class A amp and worked for 4 years until I could afford some pro-gear. Obviously 2 of these heatsink monsters were made for stereo powered by a huge ass toroid and filter caps...

author: Someone
author_rank: Super Contributor
timestamp: May 16, 2017, 01:21:46 am
content: Quote from: pitagoras on May 16, 2017, 12:23:38 amThere are extremely accurate and low drift opamps on the market, but they are A) expensive and B) not fast (but not slow either). Often you want an intentionally slow opamp to avoid instability or the need to add more compensation.....There are no generic opamps that solve all problems, which is why there is such a variety available. Even when money is no object ($10 each and up) you still can't come up with a small list of opamps that could solve most problems. You'll have to live with needing to order in speciality opamps when you need them and the old go-to parts like a TL0(5/6/7/8)(1/2/4) wont make it.

author: danadak
author_rank: Super Contributor
timestamp: May 16, 2017, 10:16:34 am
content: IA, Instrumentation OpAmps for precision laser trimmed G andCMRR work. Analog devices series.http://www.analog.com/en/products/amplifiers/instrumentation-amplifiers.htmlhttp://www.analog.com/en/education/education-library/dh-designers-guide-to-instrumentation-amps.htmlRegards, Dana,

author: capt bullshot
author_rank: Super Contributor
timestamp: May 16, 2017, 10:35:58 am
content: Low voltage, zero (marketing wise) offset / drift: OPA333 / NCV333Quite interesting if you need a diff amp with good CMRR at higher frequencies: AD830 / AD8130

author: bktemp
author_rank: Super Contributor
timestamp: May 16, 2017, 11:17:18 am
content: Quote from: technix on May 16, 2017, 12:21:01 amUsing a TL084/TL082 instead of LM324/LM358 does not always work:The input of an LM358/324 can work down to the negative rail but only 1.5V below the positive supply. TL082/84 instead can work up to the positive rail but only down to 3V above the negativ supply rail. Also the output of an LM358/324 can swing close to the negative supply rail if it does not need to sink any current, while TL082/4 can only swing to 1.5V above the negative rail.So be careful when substituting opamps.TLC2272 has a more similar input range, but only works up to 16V supply voltage.I tried avoiding LM358/324 in any new project, but occasionally it is the only one fitting a particular application:- low cost- can work close to the negative rail- operates at >16V supply voltageThe last requirement rules out many rail-rail opamps, the first one most of the remaining ones. Because LM358 is so cheap, it is often a good choice for a general purpose opamps despite all of its small problems.

author: tggzzz
author_rank: Super Contributor
timestamp: May 16, 2017, 11:21:27 am
content: One ofmanyinvaluable features in "The Art of Electronics" is the sets of tables giving the key specifications of "good example" opamps, where "good" is defined in several separate ways such as low cost, high power, etc. There are similar tables in for other types of components.So yourself a favour and buy the book. You will learn a lot of things, including things you didn't realise you needed to know

author: David Hess
author_rank: Super Contributor
timestamp: May 16, 2017, 06:29:19 pm
content: The inexpensive list:Audio and low bias current: TL071/TL072/TL074 or even better the precision version which is TL051/TL052/TL054. These can also be used in high side applications. Ignore the TL081/TL082/TL084.DC Precision: OP-07(S)Single Supply: LM358(D) and LM324(Q)Improved Single Supply: LT1013(D) and LT1014(Q)The special list:Precision and low input bias current: LT1012(S) or LT1097(S)Precision, fast, and low noise: OP-27(S) or LT1007(S) and LT1124(D)Precision single supply: LT1006(S) and LT1013(D) and LT1014(Q)Zero drift: LT1150(S) and LT1151(D) or LT2057(S)

author: f5r5e5d
author_rank: Frequent Contributor
timestamp: May 16, 2017, 07:35:25 pm
content: ouch, those LT on your "special" list are old - can find better in each category from ADI, TI, Nat(now TI) only ~ one decade oldOPA164x low noise fet input, OPA827 adds precision Vos for a premium price - only the (ancient) ADI AD743/5 betters the noise spec for a fet input - at a high input CSiGe inputs give a slightly better i_noise for low e_n bjt op amps: OPA211ADI does a poor job explaining the advantages of their "linearized input" ADA4898...

author: Muxr
author_rank: Super Contributor
timestamp: May 16, 2017, 07:47:21 pm
content: Sometimes you need a low power Op Amp for battery powered or solar powered operation. Project I am currently working on calls for one such op amp. I have selected the TLV8801/TLV8802 for the task.Haven't used it yet, but looks promising.

author: Zero999
author_rank: Super Contributor
timestamp: May 16, 2017, 10:31:04 pm
content: Quote from: BrianHG on May 16, 2017, 12:55:00 amOne thing to note about the OP37 is it's only stable for gains >5. It needs phase compensation for gains under 5 but it's easier just to use the OP27 which is the unity gain stable equivalent.

author: David Hess
author_rank: Super Contributor
timestamp: May 17, 2017, 12:57:50 am
content: Quote from: f5r5e5d on May 16, 2017, 07:35:25 pmThey support +/-15 volt supplies. I could make a more modern list for +/-5 volt supplies.Older parts also tend to be less expensive.