SEMICONDUCTOR INTEGRATED CIRCUIT

摘要

PURPOSE:To attain fast operation of an output circuit and to prevent malfunction due to reduced noise by providing a control means applying charge or discharge control to a prescribed node of the output circuit via a transistor(TR). CONSTITUTION:The output circuit is provided internally with an output control circuit outputting pulse signals P, P' controlling nodes 40, 47 of a buffer amplifier section BA. With the signal P going to '1', the node 40 is discharged through a path by TRs 41, 42 in addition to a current path of TRs 38, 39. Thus, the discharge speed of the node 40 is increased and a TR 51 is turned on rapidly and the leading of a data DOUT to '1' is made steep. The similar operation is applied also in the node 47 when the signal P' is '0' and the trailing of the data DOUT to '0' is made steep by the TR 52 turned on rapidly and high speed operation in the disable mode is attained. In case of the active mode, the nodes 40, 47 are charged/discharged slowly and no rapid current flows to the TRs 51, 52, then the occurrence of noise is decreased.