A three-dimensional integrated circuit has a plurality of layers disposed in a stacked relationship. Logic circuitry is embodied in a first layer of the three-dimensional integrated circuit. An input output circuit is electrically coupled to the logic circuitry and has a plurality of transistors embodied in at least two layers of the three-dimensional integrated circuit. The input output circuit has first and second input output circuitry, wherein the first input output circuitry operates faster than the second input output circuitry.