I am using one side of the LM358 as an error amplifier with a gain of 1, biased according to this MIT lesson for differential amplifiers.
The results below show me tuning the reference signal to see if I get the desired output error. My error = SENSE + OFFSET - REF. It appears to saturate at an output voltage (the error signal) of 500mV.
Why is this? I've checked the datasheet I have for the LM358 but cannot seem to make sense of the operating limitations, since this shows the output voltage conditions with a load attached (I am operating with no load):
What am I missing? Where on the datasheet can I find information about the minimum output voltage?
My supply is +5V to GND, so I expected the output to reach zero and stay there when my calculated error reached the negative zone.