High performance bifet complementary emitter follower logic circuit

Abstract

A high performance bipolar, field effect transistor (BiFET) logic circuit has minimal power supply requirements, allowing the circuit to be manufactured in higher density devices than current switched emitter follower (CSEF). BiFET logic circuit has a plurality of input lines and first and second output lines. A plurality of FET devices are connected in parallel each having a gate connected to a corresponding one of the input lines. Two bipolar transistors are connected as a differential pair, the parallel connection of said FET devices providing an input to the base of the first bipolar transistor while the base of the second bipolar transistor is supplied with a reference voltage. Output bipolar transistors connected as emitter followers drive the first and second output lines respectively. One of these output bipolar transistors is driven by the first bipolar transistor of the differential pair, while the other of the output bipolar transistors is driven by the second bipolar transistor of the differential pair. By dotting the collectors of the differential pair, as is commonly done in CSEF circuits, additional logic functions are obtained; however, the number of additional logic functions obtained is greater than that obtainable in CSEF circuits. Thus, the BiFET has the additional advantage of providing additional logic function and flexibility as compared with CSEF circuits.