Design And Implementation Of A High-performance And Radiation-Hardened Voltage-Controlled Oscillator

As the critical component of high performance chip in aerospace, phase-locked loop's (PLL) main functions are clock generation, synchronization and data recovery, its abnormal function has significant affect to the natural work of the whole chip system. While as the key unit, voltage-controlled oscillator (VCO) generate the output clock signal of PLLs, and its identity directly decide the capability of the PLLs. Abandant data indicate that the design of VCO is one of the most important thing of the design of the PLLs.The VCO which works in the radiant environment is susceptible to the single-event transients (SETs), and lead to phase and frequency of the output signal shift, even oscillation stop, making the PLL can not work as normal. Different structures of VCOs have different sensitivity degrees to SETs. So it is critical to design a radiant harden plan which suits all different strctures of VCOs. Moreover, the response characteristics of various VCO topology vary dramatically. For various differential VCOs, a compatible design of radiation hardened plan has become the most important thing to the design of anti-radiation VCOs even the PLLs. In the 0.18um COMS process condition, this paper has done some intensive study with the design of high performance VCOs (HPVCO) and its radiation hardened design, which has a wide tuning range from GND to VDD, high frequency from 5GHz to 6.5GHz and full swing output signal whose swing is 1.8V. The main work and research results are as follows:1. To improve the disadvantage of the traditional differential VCOs delay cell structure, the disadvantage is the tuning range is narrow and the swing of the output signal obviously changes with the control voltage changes, this thesis presents a High Performance VCO (HPVCO) structure which can be used in wide tuning range,high frequency and full swing output signal. Basing on the symmetrical load differential VCO delay cell structure proposed by Maneatis, a new type of differential VCO delay cell has been designed by introducing a swing enhanced structure, dual current structure and incentive transistor structure. The strcture has advantages of a wide tuning range from GND to VDD, high frequency from 5GHz to 6.5GHz and full swing output signal whose swing is 1.8V, so a new type of delay cell structure is proposed to achieve high frequency VCOs.2. In order to achieve radiation hardened design of the HPVCO circuit, first, the HPVCO's SET response features of various sensitive nodes and power have been analysed deeply, the SET failure mechanism and recovery mechanism have been explained. Then, using the triple module redundancy (TMR), a SET hardened structure has been designed which can be used by HPVCOs, and the HPVCO's sensitivity to SET have been reduced by redundancy. Compared to relerant research, this structure has the best effect of radiation hardened.3. To evaluate the reinforcement effect of SET to HPVCOs which based on triple modular redundancy, proposed by this paper, a TMR HPVCO territory has been designed and realized in the 0.18um CMOS process by integrating the above findings. Through the layout level simulation and verification, the results show that the SET sensitivity of HPVCOs have reduced significantlyto the level below the abnormal noisy, which prove that the TMR technology proposed by this paper can effectively reduce the SET sensitivity of HPVCOs.Finally, the general design of HPVCOs and the radiation hardened design of future research direction are prospected.