how OP AMP internal circuitry works

this is a test

A good source is National semiconductor data sheets - if you can find any of their application notes for download they often give explanations of the internal workings.

You could try reading this:

As Jim Thompson pointed out there are a few things in the book like dodgy start-up circuits that are not good practice, but if you're not actually going to make an op-amp then this probably doesn't matter too much.

Chris

This might help;

its all done with smoke and mirrors! :)

that is why you never let the smoke out! otherwise it will stop working!

Oh right cheers for that! Ill just write that onto my assignment and hand it in! The guide at

Do you have a specific op amp in mind? If not, many op amps have equivalent discrete circuit schematics. Most of them will have something like in this picture:

The differential stage is usually the first thing the inputs are connected to (with the exception of a unity gain buffer in some amplifiers).

Looks like you are going to have to do your own homework..........

snipped-for-privacy@ntlworld.com schrieb:

"IC Op-Amps Through the Ages" might interest you:

Martin.

Thank you martin this is more than I could have wanted, its perfect and will go a very long way to aid my understanding of the 741. Thank you

Rappinglove schrieb:

It's nice to learn you find this nourishing. It concentrates on the old designs and has little on modern developments like CMOS, BICMOS and rail-to-rail (on input, output, or both) Op-Amps.

You may also be interested to learn that all-NPN output stages are possible, see some of the MC3307x, MC3317x and MC3327x datasheets (where x=another digit).

Martin.

Well, if you look at newer data sheets, in most cases the real circuit isn't provided because it's considered a competitive trade secret. Even in academic papers today there's often an active effort aimed at being somewhat vague as the research is funded by a particular company and said company isn't too keen on giving away any more information than it has to.

If your library has a copy (it's unfortunately out of print), I'd suggest taking a look at "Intuitive IC Op Amps" by Frederiksen

---Joel Kolstad