Op-amp specs tutorial?

[Bored@Work]

He, I am sure if you take http://www.ti.com/lit/an/slod006b/slod006b.pdf , condense it into a ready-to-use script for a one-hour video [a Dave-hour, aka 1:15], and pitch it to Dave, that Dave would consider it.

Here's an idea, since you are such an opinionated expert on absolutely every facet of EE why don't you do it.

Pearls before swine. Why repeat for the 1001st time what others have already nicely written up?

Just a couple of short observations. Certainly happy to read that I'm not the only person who finds one or two of the regular posters to be as obnoxious as humanly possible;

Why not join my fan club then? You know, I find people like you disgusting. Backstabbing people who can't name names, and prefer unspecific accusations using "one or two people", "some", "they" etc. instead. Put on your man pants.

[Stephen Hill]

Internet forums never change...

[george graves]

What would happen if we all start flagging Bored@Works posts?

[Psi]

What would happen if we all start flagging Bored@Works posts?

It would make the issue worse, like poking a bear with a stick.

[andyturk]

Wouldn't it be hilarious if Bored@Work was actually Dave's sock-puppet? Wearing a "I only give negative feedback" t-shirt, of course.

LOL

[Rerouter]

felt this might help out a little, and get the thread back on topic before it gets canned, 

http://www.ti.com/lit/ml/sloa083/sloa083.pdf

its from texas instruments "op amps for everyone" and if you struggle at understanding op amps, it is a good place to start,

and i even get what the original poster was alluding too, an off the cuff (aka unstructured) video pointing out positives and negatives and importance of various functions in non-monotone voice, but i aslo agree with the flip side that the level of information you need to grasp (not that much is actually math) before you see why those parameters matter, and what you need to watch out for when designing circuits, e.g. common mode input voltage range bites a whole lot of new comers when they realise there 0.2V signal is too small for the op amp to even recognise,

there are also behavioural parameters, more commonly shown in a graph for transients, these are things like if it follows a QAD (quater amplitude decay generally known as the sweetspot for how long it is out of regulation) or its slew rate (how quickly it can change its output) and settling time for a given transient (generally give to a % meaning how long it took to become stable within that percentage)

seriously there is atleast a 10 minute video on just about each of them, and it is no easy task, but in truth a whole lot of it is based on understanding, with the math generally not passing much more than highschool algebra, though it is not uncommon for them to use symbols to represent a constnat (number), but that is generally not that hard to track down,

so read a book or 2, take in what you can and ask for help with the rest, after all that is one of the functions of a forum.

[Psi]

felt this might help out a little, and get the thread back on topic before it gets canned, 
http://www.ti.com/lit/ml/sloa083/sloa083.pdf

Thanks for that, it looks quite good.

[george graves]

bored at works posts make my week
he knows more than you

Funny - I've never seen any of his work.  Link?

[poptones]

[Noize]

bored at works posts make my week
he knows more than you

Funny - I've never seen any of his work.  Link?

I came back from the pub a bit pissed and made up a limerick. Not being serious.

[free_electron]

I hope you realise the the function of 'woof' contains a negative zone.. So it must contain a tunnel diode !

[GK]

A small hint.
Practical Op-Amps have a parameter called bias current. This is the small current that the Op Amp draws from it's input pins. If you feed the inputs from very different impedances, you will get an unwanted offset voltage. So, try to keep the input impedance of the connected circuitry the same on both inputs and the offset voltages will tend to cancel out.

This was basically true for all cases back in the good old days, but now a lot of op-amps are designed with input bias current cancellation. For these parts the maximum input bias current offset error often specs worse that the typical input bias current!

For these op-amps, deliberately equalising the DC impedances beween the inputs can actually make the total input offset error worse.

Here is a relevant applications note explaining the issue:

http://www.analog.com/static/imported-files/tutorials/MT-038.pdf

[deephaven]

A small hint.
Practical Op-Amps have a parameter called bias current. This is the small current that the Op Amp draws from it's input pins. If you feed the inputs from very different impedances, you will get an unwanted offset voltage. So, try to keep the input impedance of the connected circuitry the same on both inputs and the offset voltages will tend to cancel out.

This was basically true for all cases back in the good old days, but now a lot of op-amps are designed with input bias current cancellation. For these parts the maximum input bias current offset error often specs worse that the typical input bias current!

For these op-amps, deliberately equalising the DC impedances beween the inputs can actually make the total input offset error worse.

Here is a relevant applications note explaining the issue:

http://www.analog.com/static/imported-files/tutorials/MT-038.pdf

Thanks GK, an enlightening article. I guess it shows my age that I didn't qualify my statement that it only applies to non-internally compensated op-amps, they probably weren't around when I was first taught about this stuff. This doesn't just apply to op amps but anything with a differential input.

[Bambur]

There is this handbook on opamps by Analog Devices. It is free. It has chapters on very basics and pretty advanced stuff, e.g. chapters 1-2 and 6, correspondingly. It gives theory and practice well balanced. It is worth reading it in my opinion. Though I would prefer video to reading

http://www.analog.com/library/analogDialogue/archives/39-05/op_amp_applications_handbook.html

(Sorry if somebody has already suggested it.)