Input output for an integrated circuit

A method of using a three-dimensional integrated circuit having a plurality of layers disposed in a stacked relationship, wherein logic circuitry having one or more transistors is embodied in a first layer of said three-dimensional integrated circuit, an input output circuit electrically coupled to said logic circuitry has a plurality of transistors embodied in at least two layers of said three-dimensional integrated circuit, said input output circuit comprising first input output circuitry adapted to operate at a first speed, and second input output circuitry adapted to operate at a second speed that is slower than said first speed, the method comprising:

• providing electrical power to said three-dimensional integrated circuit;
• generating a first signal in said logic circuitry embodied in said first layer of said three-dimensional integrated circuit;
• providing said first signal to said first input output circuitry of said three-dimensional integrated circuit;
• outputting, at said first speed, said first signal from said input output circuitry to a component external to said three-dimensional integrated circuit;
• receiving and processing said first signal in said external component;
• generating a second signal in said logic circuitry embodied in said first layer of said three-dimensional integrated circuit;
• providing said second signal to said second input output circuitry of said three-dimensional integrated circuit;
• outputting, at said second speed, said second signal from said second input output circuitry;
• and
• receiving and processing said second signal external to said three-dimensional integrated circuit.

A method of making a three-dimensional integrated circuit including logic circuitry having one or more transistors and embodied in a first layer of said three-dimensional integrated circuit, an input output circuit electrically coupled to said logic circuitry and having a plurality of transistors embodied in at least two layers of said three-dimensional integrated circuit, said input output circuit including first input output circuitry adapted to operate at a first speed, and second input output circuitry adapted to operate at a second speed that is slower than said first speed, said method comprising:

• designing the layout of said logic circuitry and the layout of said first input output circuitry;
• designing the layout of said second input output circuitry;
• and
• storing said layouts in non-transitory machine readable storage media useable to fabricate said three-dimensional integrated circuit.