OUTPUT CIRCUIT BLOCKING POWER SUPPLIED FROM THE EXTERNAL BY CONTROLLING IMPEDANCE OF AN OUTPUT DRIVER

摘要

PURPOSE: An output circuit is provided to prevent the signal from the external through the DQ terminal by blocking the supply of the power at the dip power down mode and maintaining the output driver a high impedance state. CONSTITUTION: An output circuit includes a first switch, an output buffer, an output driver, a second switch and a third switch. The first switch a first external power as a second external power by supplying the first external power in response to the control signal or blocks the supply of power. The output buffer outputs the input signal, the enable signal and the signal to maintain the voltage of the second external power or the ground voltage in response to the control signal. The output driver outputs the signal to maintain the potential of the second external power or the ground potential in response to the control signal. The second switch maintains one of the input terminals of the output driver with the potential of the first external power in response to the control signal. And, the third switch maintains another of the input terminals of the output driver with the ground potential in response to the control signal.