A Study of Total Dose Mitigation Approaches for Charge Pumps in Phase-Locked Loop Applications

An analysis of charge pump design for improved radiation tolerance of phase locked loops is presented. Two radiation-hardened-by-design approaches are considered to mitigate the total ionizing dose damage of the circuit, and a thick-film SOI SiGe process technology has been used to reduce charge collection of single event strikes. The results show that a modified design approach to implement the charge pump using SiGe HBTs can provide advantages in radiation tolerance to improve tri-state leakage performance, particularly for missions expecting large accumulated doses.