Fan-in

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An AND gate with three inputs has a fan-in of 3.

Fan-in is the number of inputs a gate can handle. For instance the fan-in for the AND gate shown in the figure is 3. Physical logic gates with a large fan-in tend to be slower than those with a small fan-in. This is because the complexity of the input circuitry increases the input capacitance of the device. Using logic gates with higher fan-in will help reducing the depth of a logic circuit.

See also[edit]

  • Fan-out, a related concept, which is the number of logic inputs that a given logic output drives.