I'm having difficulties finding information on how repeatable the output of an opamp in this simple comparator configuration is. Give the following schematic:
I do know that a real opamp has a non zero input offset voltage, so the actual differential voltage required to make the output 0V might be a couple of mV for a jellybean opamp. So in the example above, the actual voltage might be 2.503V and might also drift with temperature, but assumed the temperature stays constant, how repeatable is it? Repeatable meaning at two points in time, how different can the input voltages be so the output is the same?
Unfortunately, not being an EE, I cannot figure out how to read an opamp datasheet properly. How do I find out how repeatable the output an opamp really is?
Bonus question: Is the output from an opamp more repeatable than the output from a comparator or a schmitt-trigger? How can I find this out from looking at the datasheet?
PS: I've run some tests with an LM393 and a 74hc14 and with the voltage references and multimeters that I have access to, I pretty much don't see a difference. Changing the input by 10µV reliably changes the Output between 5V and 0V (at a different absolute voltage of course).
To elaborate on the purpose: The input is an analog signal with a relatively high resolution. I'm not interested in the actual value of the analog signal, but I need to know exactly when it crosses a certain threshold. The absolute value of the threshold doesn't matter as long as it stays as constant as possible.