What does "fan out" refer to in a logic circuit?

"Fan out" in a logic circuit specifically refers to the number of outputs that can be driven by a single output from a circuit without degrading the performance of the circuit. It is a crucial specification as it determines how many logic inputs can connect to one output while still maintaining a reliable signal level.

When an output drives multiple inputs, each added load can affect the voltage level and the overall performance of the circuit. Typically, logic families have a specified fan-out number which indicates how many inputs can be connected to one output. For example, if a circuit has a fan-out of 3, it means you can reliably connect the output to three inputs of another circuit.

Understanding fan out is vital for designing digital systems to ensure that the outputs do not get overloaded and can function correctly across the entire system without signal degradation.