# Op-amp - Slew-Rate vs Exponential Output

I'm having some difficulty understanding why an op-amp has an exponential response even if its slew-rate is infinite?

Isn't the exponential response of the op-amp output caused by the parasitic capacitances of the internal op-amp structure (CGS, CGD, etc.). And the slew-rate is caused by output capacitance?

I'm having some trouble distinguishing the two. I always thought that the exponential response of an op-amp to a step input was due to capacitances.

Now if you study linear systems in general (such as simple RC circuits) you will see that single-pole linear systems have exponential responses (if I understand what you mean by "exponential response"). That is, the response to a step input has the form $$\y(t) = A\left(1-\exp(t/\tau)\right)\$$