Complementary transistor inverting emitter follower circuit

Abstract

A complementary bipolar transistor circuit characterized by low power dissipation and fast response for driving capacitive loads in response to input logic signals. An emitter follower series-connected pair of complementary transistors provide an output signal at the junction between their commonly connected emitters. The NPN transistor of the pair of transistors is directly driven by an input signal applied to its base. The PNP transistor of the pair of transistors is driven through a second series-connected NPN transistor and Schottky diode, the second NPN transistor base also receiving said input signal. The forward voltage of the Schottky diode is less than the V.sub.be of the PNP transistor. The PNP transistor nominally is held off and conducts only on negative-going input signal transitions to discharge the capacitive load. The NPN transistor of the pair of transitors conducts only on positive-going input signal transitions to charge the capacitive load. The circuit can be extended to perform NOR logic and to provide a pair of output signals in phase opposition to each other.