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Title Phase-locked Loop with True Random Number Generator for Reference Spur Reduction
Authors (Eojin Lee) ; (Seung-Myeong Yu) ; (Yunha Kang) ; (Junyoung Song)
DOI https://doi.org/10.5573/IEIESPC.2021.10.2.146
Page pp.146-150
ISSN 2287-5255
Keywords Phase-locked loop; True random number generator; Reference spur
Abstract This paper presents a phase-locked loop (PLL) that reduces reference spurs by using a true random number generator (TRNG). In conventional PLLs, a frequency component of the reference clock appears spurious tones in the voltage-controlled oscillator (VCO) output. In the proposed PLL, the TRNG randomly delays UP/DOWN signals which result in inconsistent timing of charging/discharging at the output of the charge pump (CP). As a result, the CP output disperses the reference spur of the VCO output by making the reference clock frequency component uneven.
The proposed PLL was fabricated in a 180-nm CMOS technology. It dissipates 23 mW at 2-GHz with 1.8-V supply and achieves more than 23 dB of additional spur suppression.