A Study of Total Dose Radiation Effects in Ka-Band Fractional-N PLLs in 45nm SiGe BiCMOS

Two fractional-N phase locked loops (PLLs) with high-performance CMOS and bipolar VCO permutations were designed in a 45nm SiGe BiCMOS process to study their sensitivity to total ionizing dose (TID) radiation effects. Special attention is paid to the total dose degradation mechanisms in the VCO, charge pump, and divider design, with wafer level device characterization carried out to support system level radiation measurements. The PLL designs operate with a tuning range of 21.53% from 29GHz to 36GHz, while achieving a jitter FOM of -228dB in fractional-N mode. Furthermore, the PLLs were tested using a TRIGA reactor to verify post-irradiation phase noise performance up to a total dose of 350krad.