A Radiation-Tolerant All-Digital Phase-Locked Loop With Fast Recovery From Single-Event Effects

This article presents a radiation-tolerant all-digital phase-locked loop (ADPLL) with fast recovery from single-event effects (SEEs) occurring in the inductor of the LC oscillator. The proposed ADPLL can detect the phase error due to SEEs and track the frequency error by switching the bandwidth of the loop. Heavy ion tests confirm that our proposed fast recovery technique significantly decreases the recovery time under different linear energy transfers (LETs). Laser tests were conducted to further study the recovery process. When exposed to 3-nJ laser pulses at 1064 nm, the recovery time is reduced from 37 to $6~{\mu }$ s. In steady state, the ADPLL operates at 2.56 GHz with a power consumption of 14.6 mW and an integral jitter of 0.3 ps from 12 kHz to 20 MHz.