I am assembling a simple follower circuit and am confused about its behavior. In the diagram below, R1 = R2 = 15 k\$\Omega\$. As expected, the voltage at the non-inverting input of the op amp is 2.5V. I expect the output at Vout to also be 2.5V. When I use a 741 for the op amp, everything works as expected and Vout is 2.5V.
However, when I use the 3130EZ op amp, I find a significant voltage drop between the inverting and non-inverting inputs (which seems to violate one of the fundamental op amp principles) and Vout is not 2.5V. I've tried varying the voltage supply to the op amp from about 5V to 15V and this causes Vout to change. I've also tried replacing the op amp and the results are the same. Any ideas why the 3130EZ would behave so differently from the 741? I'm pretty new to op amps and electronics in general, so it's possible I've missed something really obvious.