Opamp architecture VS practical usage

[maxporter]

Good morning,

Recently I've been looking into Opamp/OTA design. While there are tons of readings available, most are quite theoretical. But I’m kind of lost which architecture is best for certain applications. Does anybody know some good literature, which not only explains the OTA/Opamp, but also it’s practical usage and pitfalls? To give an example, which I’m currently looking at: a non-inverting opamp. Could a two stage OTA (5T OTA + CS output stage) work, is a single ended folded cascode opamp a better choice etc?

Thanks in advance
Max

 

[dick_freebird]

I'd bet that most op amp vendors have selection guide app notes.
There are texts out there, op amp cookbooks and op amp principles.
But unless this is idle curiosity, let the application point you at what
you specifically need to know. You can spend a lot of time reading
stuff that is true and not immediately helpful. Which is fine if you've
got leisure time, but not fine if you're on the clock.

 

[maxporter]

Thanks for responding, I really appreciate it.
Idle curiosity, true. I tend to overthink things. Regarding the app notes of vendors: my interest was chip design related, not so much application. So, for example the non-inverting opamp/buffer which I mentioned: I guess topology choice is not something I can distill from app notes?
Regards,
Max

 

[dick_freebird]

A lot of the time "secondary" interests drive the selection of style
and finer params then, to choose between surviving candidates.

For example an extremely high BW and no great concern for Vio,
you might pick a CFA; inside a PWM controller, the controlled weak
output current of a OTA can easily be overridden or summed-to.

Generally a datasheet will highlight the intended application and
the top-line benefits the part claims to deliver.

 

[BradtheRad]

An excellent resource is the Linear Databook and its variations. Published by National Semiconductor Corporation. Comprehensive (or close to it) list of IC's. A vast portion are op amps. Descriptions, specs, operating tips, graphs, schematics and sample applications. Updated every year or so. My 1982 edition is 2000 pages, 3 inches thick.

We widen our knowledge of electronics by perusing lists like the above book, as well as supply catalogs. It's vital to discover what is the range of available devices. It's a springboard for ideas about making our own projects and inventions.

Among the variety of Linear databooks is one devoted to op amps. New and old copies seen on Ebay and Amazon.

In addition to op amps of the everyday style, there are:

* instrumentation amplifiers
* rail-to-rail output type
* Norton type (current inputs rather than voltage inputs)
* Audio amplifiers (example LM386, TDA 2002)
* Radio functions
* Comparators (presents a path to ground)

 

[maxporter]

An excellent resource is the Linear Databook and its variations. Published by National Semiconductor Corporation. Comprehensive (or close to it) list of IC's. A vast portion are op amps. Descriptions, specs, operating tips, graphs, schematics and sample applications. Updated every year or so. My 1982 edition is 2000 pages, 3 inches thick.

We widen our knowledge of electronics by perusing lists like the above book, as well as supply catalogs. It's vital to discover what is the range of available devices. It's a springboard for ideas about making our own projects and inventions.

Among the variety of Linear databooks is one devoted to op amps. New and old copies seen on Ebay and Amazon.

In addition to op amps of the everyday style, there are:

* instrumentation amplifiers
* rail-to-rail output type
* Norton type (current inputs rather than voltage inputs)
* Audio amplifiers (example LM386, TDA 2002)
* Radio functions
* Comparators (presents a path to ground)

Thanks, I will definitely check it out.

 

[dick_freebird]

archive.org has a pile of IC databooks, scanned and ready.

Older is often better, for applications content. I've noticed the
"back matter" in datasheets is getting real thin, sometimes zero,
while old National databook part pages might have several dozen
application figures and pages of eyeball charts for non-line-item
behaviors. TI versions of those datasheets are pretty thin.

 

[danadakk]

A great foundational archive :

https://philbrickarchive.org/

Authors Graeme and Huelsman many books at the early stages


Bob Pease on nuances :

Bob_Pease_Lab_Notes_Part_1 : Free Download, Borrow, and Streaming : Internet Archive

archive.org

Internet Archive: Digital Library of Free & Borrowable Books, Movies, Music & Wayback Machine

archive.org

Regards, Dana.

 

[maxporter]

Thanks all for the feedback so far. Will have to reserve some reading time, to distill my needs.
Regards,
Max