Patent ID: 7492623

Claim:
An option circuit of a semiconductor chip, comprising: a first option circuit that is set before packaging the semiconductor chip to generate a first option signal; a second option circuit that is set after packaging the semiconductor chip to generate a second option signal; and a selection circuit configured to: select one of the first option signal, the second option signal, and a mode register set (MRS) signal in response to at least one control signal; and output a first selected signal as a final option signal; wherein the selection circuit comprises: a logic circuit configured to choose between the first option signal and the second option signal or to replace the first option signal with the second option signal; a first selector configured to: select one of an output signal of the logic circuit and the MRS signal in response to a first control signal; and output a second selected signal; and a second selector configured to: select one of the second selected signal and the first option signal in response to at least one second control signal; and output the first selected signal as the final option signal.