Radiation Hardened by Design-based Voltage Controlled Oscillator for Low Power Phase Locked Loop Application

A radiation-hardened-by-design (RHBD) current-starved-ring voltage-controlled oscillator (CSR-VCO) design is proposed based on the separation of gate input technique to mitigate single event effects (SEEs) for phase-locked loop (PLL) implementation. A double-exponential (DE) current model is used to analyze the effect of single event transient (SET) at the output of the proposed RHBD CSR-VCO. The proposed RHBD CSR-VCO is implemented in United Microelectronics Corporation (UMC) 65 nm CMOS technology and a 71.6% improvement is achieved in phase displacement as compared to conventional VCO. The oscillation frequency of 1.75 GHz is obtained for the proposed RHBD CSR-VCO with a tuning range from 0.40 GHz to 2.23 GHz and power dissipation of 1.368 mW. The proposed RHBD CSR-VCO is protected against radiation with deposited charges up to 1050 fC and achieved a higher figure-of-merit (FOM) when compared to the recently reported VCOs and PLLs. This shows that even in a radiation-prone environment, the RHBD PLL can achieve excellent performance and be employed successfully in low-power, high-speed communication applications.