This paper describes a digitally-controlled oscillator (DCO) design for IEEE 802.15.4a compliant ultra-wide band (UWB) transceiver systems in the mandatory channel-9 of 7.9872GHz. To achieve good immunity against noise coupling, an LC based DCO is designed. For a small inductor area, the DCO is designed with the output frequency twice the channel-9 frequency. The DCO with a triple-input control achieves the maximum frequency of 17.2GHz with nearly 40% tuning range by employing a 6-bit binary-weighted capacitor bank, a 32-bit thermometer-coded capacitor bank and a 6-bit current steering DAC. The DCO is implemented in 65nm CMOS, and the measured phase noise of - 99.3dBc/Hz at 1MHz offset is obtained at 12.4GHz output.