An ultra-high-speed direct digital frequency synthesizer implemented in GaAs HBT technology

This paper presents a 10-GHz 8-bit direct digital synthesizer（DDS） microwave monolithic integrated circuit implemented in 1μm GaAs HBT technology.The DDS takes a double-edge-trigger（DET） 8-stage pipeline accumulator with sine-weighted DAC-based ROM-less architecture,which can maximize the utilization ratio of the GaAs HBT＇s high-speed potential.With an output frequency up to 5 GHz,the DDS gives an average spurious free dynamic range of 23.24 dBc through the first Nyquist band,and consumes 2.4 W of DC power from a single-4.6 VDC supply.Using 1651 GaAs HBT transistors,the total area of the DDS chip is 2.4×2.0 mm~2.