I'm a programmer and self-taught digital designer, and I thought I could deal with an op-amp even though I haven't for over 20 years.
Quick version: I'm taking an analog 0-3.3 V signal and turning it into a 0-5 V signal using a single-supply op-amp in non-inverting mode with a voltage follower after that, powered at 10 V.
All worked fine, and then suddenly the voltage follower output died.
More detail: I have an analog signal (not PWM, true ADC) coming out of an ARM processor at max. 3.3 V. I'm using a 14-pin, four op-amp chip, in this case a TLC2274 which I bought to replace the 30 year old MC3403 I had laying around, which would not go down to the negative supply as my memory and the spec said it would.
I'm going into one of the op-amps on the chip and using a 4.7 kΩ resistor from the output to the negative input and 5.6 kΩ and a 5 kΩ trimpot to GND to convert to 5 V.
I then go into two other op-amps on the chip as voltage followers, one to each of two outputs. One is just going to an analog meter for "visualization", the other is right now doing the same but is intended to go over a long line to a motor controller.
Still in testing, I have the "main" output going to an analog mA meter with an appropriate resistor, and a scope.
All was fine and then suddenly the "main" op-amp output died. The input looks good, the output is 0 V, as is of course the negative input. No noticeable overheating, or "Magic Smoke".
I don't know the impedance of the motor controller, and the 100 ft cable will add its own problems, but I'm sitting testing on a bench and it failed, how can I prevent that?
Does one normally use a resistor, resistor plus Zener, or something else to protect an op-amp output? I'm not seeing that in "Art of Electronics" or any of my (old) op-amp circuit books. If it dies on the bench, what do I do in the real world? The spec says the chip is short circuit protected, could this have been static?
Is there a way to improve this circuit?
I am assuming the problem is from static, but not sure if it could be something else, so what could be the reason for the failure since I have no voltages available beyond the supply and GND, to which the part is protected from shorts.
Is there a way to protect the op-amp I'm using? One comment already suggested a 100 Ω resistor, but that's to compensate for the cable that has not yet been connected.