An RHBD Technique to Mitigate Missing Pulses in Delay Locked Loops

A radiation-hardened-by-design (RHBD) voltage- controlled delay line (VCDL) for single-event mitigation in delay-locked loops (DLLs) is proposed. A modified fully differential delay cell topology is used to harden the VCDL, resulting in a dramatic reduction of the missing pulses generated by the DLL after an ion strike. By increasing the width-to-length ratios of the feedback transistors of the VCDL delay cells, this topology provides substantially reduced single-event errors while maintaining high operating frequency, wide tuning range and small area penalty.