I have a project that I am working on that will use an opamp to buffer a DC signal to a number of adjustable power regulators. The opamp circuit will be arranged as a voltage follower with with the power supply rails across a pot, pot wiper tied to the opamp input. I know that most (if not all) opamps are not able to drive the full voltage of their power supply rails. From my understanding, even rail-to-rail opamps have some margin. I don't think I have a need for a rail-to-rail opamp, but I am having a hard time determining from the datasheet how much margin is required to stay in spec on parts I'm considering. Do I just not know the name spec I am looking for? Do I need to derive this number from more than one datasheet spec? Thanks!
-EM