Abstract: Monolithically integrable logic circuit having at least one NAND function and a Darlington stage serving as the signal output of the circuit, including a differential amplifier having its non-inverted output connected to the input of the Darlington stage, the differential amplifier including at least two identical input transistors with control electrodes which form the signal inputs of the circuit and a reference transistor which is identical to the input transistors, the reference transistor having one of its current carrying electrodes connected to the same current carrying electrodes of the input transistors, a current source connected to the connection of the input and reference transistor electrodes, and a switch-over system including transistors and diodes for switching the input transistors to different threshold voltage values, the switch-over system being connected to the control electrode of the reference transistor.