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Unity gain amplifier stability
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David Hess:
You have to raise the noise gain.  An easy way to do this is to place a resistor between the inverting and non-inverting inputs.  If you consider the amplifier as non-inverting with the minimum stable gain, then connect the feedback divider to the non-inverting input instead of ground.  Usually this is done through a coupling capacitor to remove errors at DC and low frequencies.
sam[PS]:
Well lot of very in depth answer there, probably too much for an arduino guy. By the way congratulation for daring to venture in analog territory, it's like coming from city to jungle it can be terrifying but so much great things to see here, so much unique species.

I would emphasis on "if the datasheet tells you it's not, use another OPAMP"

But moreover, as a simple basic rule avoid driving a capacitive load with an opamp. And the bad news here is your arduino/mcu input port are basically capacitive load, but it should be low enough capacity in most case.
99% of the time you will be using almost the same circuit arrangement so find an opamp that works for those and just stick to it. The famous maxim "if ain't broken ain't fix it" does apply in analog too. Just as an exemple, when mixing opamp based analog and MCU i've been using LM324 countless time with no stability issu so far. Don't forget good PCB layout practice : short trace on critical signal.

Of course there is the 1% remaining cases and i'm sure some will be prompt to try to prove what i just say is totally wrong based on what might happens in those particular case. Let's put it this way, this 1% is what separate a great EE engineer (aka analog guru) from an average one and it takes more than a textbook to get there. But you can make a decent career just applying simple recipes and just accept that once in a while it will not work.

If you want some kind of textbook on the matter, most of my understanding of opamp stability comes from an excellent white paper on the subject by TI (or it might be AD, just check). The TI "analog engineer cookbook" and/or the older "handbook of operational amplifier" are must read, there is so much in those including practical pcb advice that i never found in any other opamp textbook. In general both TI and AD application engineers are true analog gurus and i strongly encourage anyone who want to get deeper into the subject to check for their literature.

Just my 2cts...
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