Digitally Controlled Oscillator Design using Three Transistor XOR and NAND Gates

DCO designs using delay cells based on novel three transistors XOR and NAND gate have been reported in this paper. Two different design techniques for delay cell have been presented. Output frequencies have been controlled digitally with control world of different lengths. Three bit controlled DCO shows output frequency and power variation in the range of [3.3619–3.6298] GHz & [1.138–2.0950] mW. Five bit controlled DCO shows frequency and power variation of [1.9396–2.1361] GHz & [1.8982–3.4917] mW respectively. Moreover, seven bit controlled DCO shows frequency and power consumption variation of [1.3878–1.5287] GHz & [2.6574–4.8900] mW respectively. Further, three bit controlled DCO with delay cell-II shows frequency and power variation of [2.0456–2.5800] GHz & [1.2130–4.0813] mW. Finally five bit DCO with delay cell-II shows frequency and power variation of [1.4532–1.9986] GHz & [1.2871–6.0677] mW. Further the power consumption and output frequency of proposed circuits have been compared with earlier reported circuits and present approach shows significant improvements.