Data output circuit with reduced output noise

Abstract

A data output drive transistor is rendered conductive when the potential of an internal node attains an H level, whereby an output node is discharged to the level of ground potential. When the drive transistor is turned on, the output node is discharged to the level of ground potential at high speed. This drive transistor is turned on for a predetermined time period when output of a high level data is completed, whereby the output node is discharged to the level of the ground potential for a predetermined time period. As a result, the potential of the output node is lowered from a high level to an intermediate level, so that the amplitude of a subsequent output signal is reduced. An output circuit that can effectively prevent generation of ringing with no increase in the access time is provided. A countermeasure is provided to suppress a ringing at output node which drives the output node at high speed when the output node potential attains a potential at which no ringing is caused. A stable output signal is provided at high speed.

1 - 62 . (canceled)  
     
     
         63 . A semiconductor device comprising: 
 an output circuit for transmitting a signal of a logic corresponding to a logic of an internal signal on an internal node to an output pad via an output signal line; and a lead frame coupled to said output pad, wherein    said output circuit comprises:    a first drive element coupled between said output signal line and a reference voltage supply node, and responsive to said internal signal for being rendered conductive for driving said output signal line to a voltage level on said reference voltage supply node with a first current driving capability, and    a second drive element connected between said output signal line and said reference voltage supply node, and arranged at a position closer to said output pad than said first drive element is, and rendered conductive at a timing later than said first drive element in response to said internal signal for driving said output node to a potential level on said reference voltage node with a second current driving capability greater than said first current driving capability.    
     
     
         64 . The semiconductor device according to  claim 63 , wherein said output circuit further comprises a protection element coupled to said output line at a position between said output pad and said first drive element, for emitting a surge voltage on said output pad to said reference voltage supply node or to a second power supply node.  
     
     
         65 . The semiconductor device according to  claim 63 , wherein said output pad is connected to said lead frame via a bonding wire.  
     
     
         66 . The semiconductor device according to  claim 63 , wherein 
 said first driving element comprises an insulated gate field transistor, and    said second drive element comprises an insulated gate field effect transistor having a junction capacitance between an impurity region and a substrate region greater than said first drive element has.    
     
     
         67 . The semiconductor device according to  claim 64 , wherein; 
 said protection element is coupled to said output line at a position between said first drive element and said second drive element.