PURPOSE: To eliminate a cause to malfunction by reducing waveform distortion when a level of an output terminal is driven to be low from a high level without much loss of a substantial function of the digital output circuit.
CONSTITUTION: The circuit is provided with an output section 2 using bipolar transistors(TRs) Q1, Q2 to apply pull-down drive to an output terminal 1 toward a reference potential side so as to apply pull-down drive to the output terminal 1 with a MOS TR in on/off drive in the same phase with the bipolar TRs Q1, Q2 in a slightly faster timing than that of the bipolar TRs Q1, Q2 toward the reference potential in an auxiliary way. Thus, a current drawing capability is stepwise increased when a level of the output terminal 1 is being descended from a high level to a low level to relax the transient phenomenon at the start of current drawing.
HITACHI MICROCOMPUTER SYST