I'm looking for a good book on op-amp design. I don't mean using opamps, but rather design of operational amplifiers from discrete components. Specifically I'm looking for designs based on differential pairs, and how to improve linearity and frequency response. (It would also be nice to have some details about cascode configurations and other higher frequency designs)
Basically, I have done a few op-amp based designs, but would like some more info on how to improve them. I'd also like to stay away from IC design/fab and similar stuff.
Can anyone be of help?
Thanks
-Dan
Basically, I have done a few op-amp based designs, but would like some more info on how to improve them. I'd also like to stay away from IC design/fab and similar stuff.
Can anyone be of help?
Thanks
-Dan
I realize you explicitly don't want IC design books, but go to a university library or technical book store and take a look at the following books:
Analysis and Design of Analog Integrated Circuits (4th Edition)
by Paul R. Gray, Paul J. Hurst, Stephen H. Lewis, Robert G. Meyer
John Wiley & Sons; ISBN: 0471321680
Bipolar and Mos Analog Integrated Circuit Design
by Alan B. Grebene
John Wiley & Sons; ISBN: 0471430781
Design of Analog Integrated Circuits and Systems
by Kenneth R. Laker, Willy M.C. Sansen, William M. C. Sansen
McGraw-Hill Science/Engineering/Math; ISBN: 007036060X
These aren't exactly what you want, but they are heavy duty books on how to design ICs, including op-amps. The principles are mostly the same with discrete components, except that you have different constraints. When designing an IC, the basic passive components you can work are limited and tend to suck in absolute terms (eg resistor tolerances of 30%) , but they match very, very well within the same chip; on the other hand with discretes, matching is tedious, but you have the entire world of devices to choose from.
Looking these up on amazon might turn up other similar useful books.
-- mirlo
Analysis and Design of Analog Integrated Circuits (4th Edition)
by Paul R. Gray, Paul J. Hurst, Stephen H. Lewis, Robert G. Meyer
John Wiley & Sons; ISBN: 0471321680
Bipolar and Mos Analog Integrated Circuit Design
by Alan B. Grebene
John Wiley & Sons; ISBN: 0471430781
Design of Analog Integrated Circuits and Systems
by Kenneth R. Laker, Willy M.C. Sansen, William M. C. Sansen
McGraw-Hill Science/Engineering/Math; ISBN: 007036060X
These aren't exactly what you want, but they are heavy duty books on how to design ICs, including op-amps. The principles are mostly the same with discrete components, except that you have different constraints. When designing an IC, the basic passive components you can work are limited and tend to suck in absolute terms (eg resistor tolerances of 30%) , but they match very, very well within the same chip; on the other hand with discretes, matching is tedious, but you have the entire world of devices to choose from.
Looking these up on amazon might turn up other similar useful books.
-- mirlo
mirlo said:
I thought that with IC design you would get really good active components, which would make matching easier (or actually a non existant problem).
Anyway, Looks like these may be what I'm looking for. I'll check them out. I may just order, if they're not too expensive.
I would like to find an old copy of National Semiconductor's Linear Application Notes. I've heard good things about this book, but never seen it. I really like some of the older texts. I still like my fathers transistor book from his college days. (Some light reading before bed!)
-Dan
Here's a freebie op amp book:
From Texas Instruments "Handbook of Operational Amplifier Applications" -- it's an application report SBOA92A issued in October 2001 -- it's a collection of articles and theory from the folks at Burr-Brown.
Walt Jung's article on op-amp macromodel is still on the Analog Devices website, as are a lot of his op amp articles. The reason I point out this one is that it goes over the innards of op-amps and the pieces of theory which would allow one to build from discrete devices.
The National Semi "Linear Applications" book was put out about 20 years ago and is still very helpfu.
From Texas Instruments "Handbook of Operational Amplifier Applications" -- it's an application report SBOA92A issued in October 2001 -- it's a collection of articles and theory from the folks at Burr-Brown.
Walt Jung's article on op-amp macromodel is still on the Analog Devices website, as are a lot of his op amp articles. The reason I point out this one is that it goes over the innards of op-amps and the pieces of theory which would allow one to build from discrete devices.
The National Semi "Linear Applications" book was put out about 20 years ago and is still very helpfu.
Active devices on ICs
Active devices on ICs can indeed be quite excellent, depending on the IC fabrication process. And active device matching is generally a non-issue because devices can be laid out in interleaved patterns and made large enough to reduce mismatch. Also, IC active devices can generally be scaled (within limits) to whatever size is appropriate for their use in a circuit, and so unwanted parasitic capacitances can be minimized.
The downside of the active components on an IC is that they usually don' t come in many varieties in a given process. A BiCMOS process for analog applications might have two scalable flavors each of NMOS and PMOS, one scalable high performance NPN, and some sort of crappy PNP which is usually made from the layers designed for PMOS devices.
The passive components usually suck because they are usually made from the layers that were designed for the active devices, rather than with special layers actually designed for high performance passives. And large resistors (> 100 kOhm) or capacitors ( > 30 pF) are prohibitively expensive in area terms, so these limitations are designed around using lots and lots of active devices.
A more basic text that might be useful is the book on microelectronic circuits by Sedra and Smith, but if you can deal with the deeper treatment and analysis in books like the ones I mentioned, Sedra and Smith is a waste.
Douglas Self's amplifier design book might be useful, too. (although I can already hear the sneers and dismay brought on in some fellow DIYers by the mention of his name; he's an unabashed objectivist, but his books do offer some things of value in my opinion)
Active devices on ICs can indeed be quite excellent, depending on the IC fabrication process. And active device matching is generally a non-issue because devices can be laid out in interleaved patterns and made large enough to reduce mismatch. Also, IC active devices can generally be scaled (within limits) to whatever size is appropriate for their use in a circuit, and so unwanted parasitic capacitances can be minimized.
The downside of the active components on an IC is that they usually don' t come in many varieties in a given process. A BiCMOS process for analog applications might have two scalable flavors each of NMOS and PMOS, one scalable high performance NPN, and some sort of crappy PNP which is usually made from the layers designed for PMOS devices.
The passive components usually suck because they are usually made from the layers that were designed for the active devices, rather than with special layers actually designed for high performance passives. And large resistors (> 100 kOhm) or capacitors ( > 30 pF) are prohibitively expensive in area terms, so these limitations are designed around using lots and lots of active devices.
A more basic text that might be useful is the book on microelectronic circuits by Sedra and Smith, but if you can deal with the deeper treatment and analysis in books like the ones I mentioned, Sedra and Smith is a waste.
Douglas Self's amplifier design book might be useful, too. (although I can already hear the sneers and dismay brought on in some fellow DIYers by the mention of his name; he's an unabashed objectivist, but his books do offer some things of value in my opinion)
A good article on this by Nelson Pass. It may not have everything you want but it may be a good start. I used it to build some discreet 10A opamps that run on -+40V and can dissipate up to 500W. It seems this excellent article has be greatly overlooked since it it hidden it the older projects archive. These are all biased class A.
http://www.passdiy.com/pdf/diyopamp.pdf
Darrell Harmon
http://www.passdiy.com/pdf/diyopamp.pdf
Darrell Harmon
National Semiconductor has lots of documents.....
One good is this
http://www.national.com/an/AN/AN-A.pdf
One good is this
http://www.national.com/an/AN/AN-A.pdf
dlharmon said:
Yeah, this is a good one. I've seen it before. But, I'm actually looking for something more specific to improving design from a component standpoint. Reduction of noise, and how to improve linearity, etc, etc.
-Dan
Re: Active devices on ICs
I knew about the caps being expensive in terms of Si, but didn't think of the resistors, I guess it makes sense. I do read a lot of trade mags, and try to keep up on the semiconductor industry (Although, I do not really know a lot about the subject). Lots of neat thing being done now, with processes being shrunk and all.
Seems to me a process also affects noise. Larger generations are less noisy? Not sure where I got that from, though, so it may not be the case.
peranders: - I'm going to check out the National App note also...
jackinnj - I'm going to check out the old BB notes... ...B-B seem to be good amplifiers...
Thanks for the suggestions!
Dan
mirlo said:
I knew about the caps being expensive in terms of Si, but didn't think of the resistors, I guess it makes sense. I do read a lot of trade mags, and try to keep up on the semiconductor industry (Although, I do not really know a lot about the subject). Lots of neat thing being done now, with processes being shrunk and all.
Seems to me a process also affects noise. Larger generations are less noisy? Not sure where I got that from, though, so it may not be the case.
peranders: - I'm going to check out the National App note also...
jackinnj - I'm going to check out the old BB notes... ...B-B seem to be good amplifiers...
Thanks for the suggestions!
Dan
no book, but...
From the technical library of analog devices
http://www.analog.com/technology/amplifiersLinear/training/highspeed.html
see section 1: high speed opamps. although it contains only simplified schematics, i found it quite useful as a stimulation for thinking.
like the "quad core" stage, which i had never seen before. of course later i discovered it not so special/new, but the app note helped me find my way.
you might also want to take a look at
http://focus.ti.com/docs/analog/cat...tract.jhtml?familyId=569&abstractName=sbfa009
especially at the simplified(!) circuit models near the end. no theory but plenty of schematics. tough reading but good excercise.
some datasheets of opamps (mainly ad) have also simplified schematics with brief explanations sometimes. some app notes mainly from ad, ti/bb might also contain useful info.
ic opamps designers use some very cool tricks to get aroung all kinds of limitations and improve performance. fascinating.
The difficulty in discrete design is that you can't get the (necessary) matching of transistors that is possible in ic.
From the technical library of analog devices
http://www.analog.com/technology/amplifiersLinear/training/highspeed.html
see section 1: high speed opamps. although it contains only simplified schematics, i found it quite useful as a stimulation for thinking.
like the "quad core" stage, which i had never seen before. of course later i discovered it not so special/new, but the app note helped me find my way.
you might also want to take a look at
http://focus.ti.com/docs/analog/cat...tract.jhtml?familyId=569&abstractName=sbfa009
especially at the simplified(!) circuit models near the end. no theory but plenty of schematics. tough reading but good excercise.
some datasheets of opamps (mainly ad) have also simplified schematics with brief explanations sometimes. some app notes mainly from ad, ti/bb might also contain useful info.
ic opamps designers use some very cool tricks to get aroung all kinds of limitations and improve performance. fascinating.
The difficulty in discrete design is that you can't get the (necessary) matching of transistors that is possible in ic.
Nelson Pass said:
I had forgotten about that one. It is a great resource for about anything electronic. I got it from the library and read all 1000 pages in a few weeks. I don't think it was intended to be read like that, but I enjoyed it. It is expensive but worth it ($70). One of the authors posts frequently on sci.electronics.design and has answered a few strange questions for me. I think the 1990 version is the latest so some parts don't exist anymore.
Darrell Harmon
Re: no book, but...
Yes they do. Actually I do read a lot of op-amp datasheets. I find that National Semi also has a lot of good schematics.
I'm getting to the point that I can read a lot of the schematics like many people read the newspaper. What I need a little help with is the math behind some of the designs, so as to better understand how the circuit operates. (And to understand where to start with improvements)
mirlo Had a point about the weakness of some integrated designs (Like poor resistors). This makes me think that maybe some designs with discrete components will have advantages over integrated designs. For example, it's easy to buy 1% resistors, and match transistors. Some companies sell matched pair transistors in one case on the same chunk of silicon, all the benefits of IC, with th ability to remove more heat and use better components. As opposed to an IC, where you get matched transistors, and 30% resistors... ...which would explain why many IC's have few resistors.
Keep the suggestions coming, I'm geting them all printed.
-Dan
kyrgeo said:
Yes they do. Actually I do read a lot of op-amp datasheets. I find that National Semi also has a lot of good schematics.
I'm getting to the point that I can read a lot of the schematics like many people read the newspaper. What I need a little help with is the math behind some of the designs, so as to better understand how the circuit operates. (And to understand where to start with improvements)
mirlo Had a point about the weakness of some integrated designs (Like poor resistors). This makes me think that maybe some designs with discrete components will have advantages over integrated designs. For example, it's easy to buy 1% resistors, and match transistors. Some companies sell matched pair transistors in one case on the same chunk of silicon, all the benefits of IC, with th ability to remove more heat and use better components. As opposed to an IC, where you get matched transistors, and 30% resistors... ...which would explain why many IC's have few resistors.
Keep the suggestions coming, I'm geting them all printed.
-Dan
dkemppai
have a look at Douglas Self's site - lots of interesting stuff about amplifier design. There is a section on op-amps and discrete transistor design but also look at the power amplifier linearity stuff - the basic topology is like an op-amp and each part is examined in detail.
http://www.dself.demon.co.uk/ampins.htm
Regards
13th Duke of Wymbourne
have a look at Douglas Self's site - lots of interesting stuff about amplifier design. There is a section on op-amps and discrete transistor design but also look at the power amplifier linearity stuff - the basic topology is like an op-amp and each part is examined in detail.
http://www.dself.demon.co.uk/ampins.htm
Regards
13th Duke of Wymbourne
I found this by google search of "op-amp design" and fooling around with some of the results:
http://www.engr.colostate.edu/EE534/
The lecture link includes some PDFs about designing op-amps, and I imagine there's a lot to be found by browsing the links on this page.
http://www.engr.colostate.edu/EE534/
The lecture link includes some PDFs about designing op-amps, and I imagine there's a lot to be found by browsing the links on this page.
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