Performance of carry lookahead generator circuit fabricated with gallium arsenide

A high-performance 4-bit carry lookahead generator macrocell integrated circuit similar to the commercial 2902, a member of the 2900-family microprocessor chip set, was designed and built using direct-coupled FET logic (DCFL) and buffered FET logic (BFL) GaAs technologies. The following propagation delay times and power dissipations were measured: DCFL version -T/SUB pd/=1.55 ns, P=34 mW; BFL version-T/SUB pd/=1.10 ns, P=520 mW. In contrast, the commercially available bipolar 2902 has a propagation delay (room temperature typical) of 4.5 ns with an average power dissipation of 260 mW.