The present invention relates to a threshold amplifier suited to integrated circuit fabrication of a process employing CMOS technology. The threshold amplifier is designed to sense current producing a first or a second logic level as a function of a current threshold. The amplifier comprises a p-channel device and a n-channel device serially connected across the bias supply. The gate to source voltages of the two devices are respectively controlled by a diode connected p-channel device similarly serially connected across the bias supply with a diode connected n-channel device, the source of the latter being returned to ground via a current carrying resistance also in the second series path. The output level which is taken at the drain inter-connection between the devices in the first series path depends on the relative conductivity of the two devices which is in turn affected by the induced voltage drop in the source connected resistance in the second series path. The threshold voltage may be controlled by the geometry ratio between the n-channel devices, and the current setting in the second series path.