A very wide bandwidth digital VCO using quadrature frequencymultiplication and division implemented in AlGaAs/GaAs HBT's

摘要

A digital voltage-controlled oscillator (VCO) is described whichnuses frequency multiplication and division to achieve very widenbandwidth. The VCO uses current-mode logic and does not require reactivenelements such as inductors, capacitors or varactors. A novel, fullynsymmetric exclusive-OR (XOR) circuit was developed which uses productnpairs and emitter-coupled logic. To achieve the highest performancenpossible, the critical path is symmetric and special physical designntechniques were developed to promote matched-capacitance. The maximumnmeasured frequency was 13.66 GHz. The chip occupies 1.9 mm×1.6 mmnand dissipates 2.45 W at a supply voltage of -6.0 V. With a measurednfrequency range from 1.25 to 13.66 GHz, this circuit has the widestnbandwidth reported in the literature for any VCO, digital ornanalog