Radiation-Hardened PLL with a Switchable Dual Modular Redundancy Structure

SinNyoung KIM
Hidetoshi ONODERA

IEICE TRANSACTIONS on Electronics   Vol.E97-C    No.4    pp.325-331
Publication Date: 2014/04/01
Online ISSN: 1745-1353
DOI: 10.1587/transele.E97.C.325
Type of Manuscript: Special Section PAPER (Special Section on Solid-State Circuit Design,---,Architecture, Circuit, Device and Design Methodology)
radiation-hardened phase-locked loop (RH-PLL),  PLL,  radiation-hardened-by-design (RHBD),  dual modular redundancy (DMR),  

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This paper proposes a radiation-hardened phase-locked loop (RH-PLL) with a switchable dual modular redundancy (DMR) structure. After radiation strikes, unhardened PLLs suffer clock perturbations. Conventional RH-PLLs have been proposed to reduce recovery time after perturbation. However, this recovery still requires tens of clock cycles. Our proposal involves ‘detecting’ and ‘switching’, rather than ‘recovering’ from clock perturbation. Detection speed is crucial for robust perturbation-immunity. We identify types of clock perturbation and then propose a set of detectors to detect each type. With this method, the detectors guarantee high-speed detection that leads to perturbation-immune switching from a radiated clock to an undistorted clock. The proposed RH-PLL was fabricated and then verified with a radiation test on real silicon.