In digital circuits, what does 'fan-out' refer to?

'Fan-out' specifically refers to the number of gate inputs that a single output can drive in a digital circuit. This concept is crucial because it directly relates to the capability of a circuit to connect multiple components while maintaining signal integrity.

When an output drives multiple inputs, it has to provide enough current to each input without degrading the signal quality. If the number of inputs exceeds the output's fan-out capacity, the output may struggle to drive all the inputs effectively, leading to potential issues like increased signal delay or indecipherable logic levels. Understanding fan-out is vital for ensuring that a circuit functions correctly without overloading any individual output.

This concept underlies design decisions—ensuring that the output specifications (such as voltage and current levels) can adequately support the required number of inputs, thus maintaining reliable system performance.