Differential digital Ring Oscillator (DRO) is the block that dominates the overall performanceof the AD-PLL. It is the responsible for most of the lower power consumption, less area, lower phase noise, better frequency stability with variation of applied voltage and with investigation of temperature change effect on the oscillation frequency. In this work it is studied and projected a fully dual band differential ring Oscillator (DRO) implementation technique with the purposeof producing an extended and linear frequency range.