PURPOSE: To provide a new BiCMOS circuit operated at a higher speed than a conventional BiCMOS circuit in which higher speed operation is attained than a CMOS circuit even under a low power supply voltage of 3.3V or below.

CONSTITUTION: The circuit consists of an npn bipolar transistor(TR) 3 and a p-channel field effect TR 5, a collector of the NTN type bipolar TR 3 connects to a high level power supply terminal 1 via a load 6, its base is connected to an input terminal 4, and its emitter is connected to a low level power supply terminal, and a source and a gate of the p-channel field effect TR 5 are connected to the input terminal 4 and its drain connects to a low level power supply terminal 7. When the bipolar TR is nonconductive, since the base potential is kept to a potential level higher than the emitter potential by a turn-on voltage of the field effect TR, the time when the bipolar TR is turned on is considerably decreased and the circuit is operated at a high speed even under a voltage below 3.3V in comparison with the operation speed of a CMOS circuit of the same process.