Fan-out refers to the number of output lines that may be connected to a logic, chip
, circuit or device. The number is limited because the circuit or fan-out unit
inquestion must provide the necessary driver power
. Inaddition, if the maximum fan-out is exceeded, the then very low output impedance
inconnection with the pull-up resistor of
thedriver no longer reaches the high state of the logic signals
, so that the subsequent devices are no longer able to evaluate the signals. If the fan-out of a logic circuit is 10, for example, then ten identical load units can be connected to the output like inputs. Interconnect technologies at chip level can be implemented by means of wafer level packaging (WLP) as fan-out wafer level packaging (FO-WLP).