A High Speed Phase Locked Loop, Using an Open-Loop Phase Detector and Carbon Nanotube Field Effect Transistors

Speed, accuracy, and power consumption of electronic devices, are important parameters that should be considered in the design and manufacturing of these devices. In this paper, a new design of modified phase-locked loop, using Carbon Nanotube Field Effect Transistors, is proposed. Using a differential structure of the ring oscillator, the coupled noise of the power supply and the substrate is eliminated.  In addition, using active inductor in the oscillator delay cells will cause a marked increase in oscillation frequency. In the presented phase detector circuit, by using a new open loop structure, the detection speed increases significantly. This will remove the divider circuit on loop track. By removing the divider circuit, the noise of the loop will be reduced considrably. The designed circuit is implemented once in MOSFET technology using 0.18 micrometers process and once again in 32nm process of carbon nano-tube field effect transistors technology with 0.9 volt power supply. The center frequency in this process is 68.5 GHz. The value of power consumption is less than 150 nano-watts and the acquisition time is less than 10 picoseconds.