High-speed integrated circuits using i-AlGaAs/n-GaAs doped-channel hetero-MISFET's (DMT's)

High-speed ring oscillators and divide-by-two circuits have been fabricated by using i-AlGaAs/n-GaAs doped-channel hetero-MISFET's (DMT's) and saturated resistors in direct-coupled FET logic (DCFL) circuit architecture for the first time. The maximum operating frequency is 3.72 GHz for dual-clocked master-slave flip-flop frequency dividers based on eight NOR gates, which consist of 0.8-µm gate enhancement-mode DMT's with 370-mS/mm maximum transconductance. A 25-stage ring oscillator shows 24-