Patent ID: 8749265

Claim:
A semiconductor chip comprising: N unit cells to output an identification key of N bits, where N denotes a natural number, wherein each of the N unit cells includes a pair of inverters and a switch, and an input terminal of one inverter among the pair of inverters is connected to an output terminal of another inverter, an output terminal of the one inverter is connected to an input terminal of the other inverter, one terminal of the switch is connected to the input terminal of the one inverter, and another terminal of the switch is connected to the output terminal of the one inverter, wherein, when the switch is closed, the input terminal and the output terminal of the one inverter, and the input terminal and the output terminal of the other inverter are shorted with each other, and a voltage value of the shorted terminals corresponds to a value between a logic threshold of the one inverter and a logic threshold of the other inverter.