This paper presents a wide range DCO with fine discrete tuning steps using a ΣΔ modulation technique for UWB frequency synthesizer. The proposed discrete tuning scheme provides a low effective frequency resolution without any degradation of the phase noise performance. With its three step discrete tunings, the DCO simultaneously has a wide tuning range and fine tuning steps. The frequency synthesizer was implemented using 0.13 µm CMOS technology. The tuning range of the DCO is 5.8-6.8 GHz with an effective frequency resolution of 3.9 kHz. It achieves a measured phase noise of -108 dBc/Hz at 1 MHz offset and a tuning range of 16.8% with the power consumption of 5.9 mW. The figure of merit with the tuning range is -181.5 dBc/Hz.