Using the tail level referencing for an inverter stage immediately
following a differential amplifier provides trip point tracking with the
variations in magnitude of the output level swings on the differential
amplifier stage output over the operating range of the circuit. When the
tail voltage increases and the V.sub.OL of the differential stage
increases, the trip point of the receiving inverter also increases. When
the tail voltage decreases and the V.sub.OL of the differential amplifier
goes lower, the trip point of the inverter decreases. An additional
benefit is provided by the tail connection to the inverter. Faster
switching of current from the right side to the left side of the
differential amplifier occurs due to the tail node voltage being raised
momentarily by a transistor in the inverter stage when the input of the
inverter stage transitions high.