INPUT/OUTPUT CIRCUIT

PURPOSE:To eliminate the effect of the level fluctuation of a ground line or a power source line and to prevent malfunction from being generated, by providing an initial stage inverter, a passage control transistor, a second stage inverter, and a one-shot pulse generation circuit. CONSTITUTION:When an input signal supplied to an input terminal 1 shifts from a high level to a low level, the output of the initial stage inverter 2 shifts from the low level to the high level. In such a case, the passage control transistor Tr7 is set at an ON state, and the output of the inverter 2 passes through the Tr7, and is supplied to the next stage inverter 3, and the output of the inverter 3 is shifted from the high level to the low level. And the output of the inverter 3 is inverted by an inverter 32, and charge to a capacitor 33 is performed, and the Tr7 is set at an unenergized state during the charge via a NOR circuit 31, etc., and an output buffer 4 completes the output of data during that unenergized period of the Tr7. Therefore, the Tr7 goes to the unenergized state even when the level fluctuation is generated on the ground line or the power source line at the time of outputting the data from the buffer 4, and no fluctuation of the output of the inverter 3 is generated, then, the malfunction can be prevented from being generated.