Rongjin Xu

dblp:223/1090 · DBLP profile ↗
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5ranked-venue papers
2as first author
3since 2021 · last 2025
0000-0003-0632-2775ORCID · corroborated

Domains — the database's venue-derived domains; a paper can count in several

Systems, architecture and hardware · 5 · 2 first-author · 3 since 2021
YearPublicationVenuePosition
2025 An Integer-N Reference-Double-Sampling PLL for Frequency-Multiplied Octa-Phase Clock Generation Achieving -251.9 dB FOMJitter-N
abstract
This paper presents a reference double-sampling phase-locked loop (RDSPLL) that integrates frequency multiplication and octa-phase clock generation into a single system, significantly reducing power consumption. A differential ring oscillator (DRO) is employed to generate octa-phase clocks with high phase accuracy. The reference double-sampling technique extends the loop bandwidth, effectively suppressing phase noise from the ring oscillator and thereby reducing jitter. To achieve accurate and efficient phase error detection, we proposed a novel offset-compensated hybrid phase detector (OCH-PD), featuring an offset calibration and a comparator-ADC hybrid quantizer. The offset calibration utilizes the CDAC to dynamically compensate for the mismatch in double-sampling, improving jitter and spur performance. The hybrid quantizer supports dynamic mode switching based on different locking states: during the coarse frequency locking phase, it operates in the ADC mode to accelerate the locking process; once a stable lock is achieved, it switches to the comparator mode to enable low-power, high-speed quantization. Fabricated in a 65-nm CMOS process, the prototype achieves 674 fs RMS jitter at 2.4 GHz while consuming only 3.43 mW, resulting in a$\text {FOM}_{\text {Jitter-N}}$of -251.9 dB. With offset calibration, the reference spur at 100 MHz is suppressed from -56 dBc to -80 dBc, and the jitter is reduced from 1.42 ps to 674 fs. The locking time improves from$10.5~{\mu }$s to$1.6~{\mu }$s using the hybrid quantizer. The eight-phase accuracy remains better than 1° over the frequency range of 2-2.8 GHz.
Sirou Li, Rongjin Xu, Weijia Zeng, Kaiyun Cao, Heyu Ren, Xing Wu 0005, Liangjian Lyu, Chuanjin Richard Shi
IEEE Trans. Circuits Syst. I Regul. Pap.2
2022 A 2.0-2.9 GHz ring-based injection-locked clock multiplier using a self-alignment frequency-tracking loop for reference spur reduction
Rongjin Xu, Dawei Ye, Chuanjin Richard Shi
Integr.1
2022 Analysis and Design of Digital Injection-Locked Clock Multipliers Using Bang-Bang Phase Detectors
abstract
The analysis of injection-locked clock multipliers (ILCMs) using bang-bang phase detectors (BBPDs) is challenging due to the nonlinear BBPD and the multi-rate injected oscillator. This paper presents an explicit analysis of digital ILCMs using BBPDs and proposed an intuitive approach to optimizing parameters with given noise sources. A time-domain analysis in the single-clock domain is presented to solve the closed-form expression of jitter in the ILCM. The proposed approach exhibits good consistency with simulations, for various design parameters and noise cases. With the predicted input-referred jitter, the equivalent BBPD gain is resolved to derive the frequency-domain noise transfer functions in concise forms. To achieve the desired performance with given specifications, recommended design procedures are summarized based on the proposed analysis and verified by simulations.
Rongjin Xu, Dawei Ye, Chuanjin Richard Shi
IEEE Trans. Circuits Syst. I Regul. Pap.1
2020 A 400 MHz, 8-Bit, 1.75-ps Resolution Pipelined-Two-Step Time-to-Digital Converter with Dynamic Time Amplification
abstract
This work proposes a high-speed pipelined-two-step time-to-digital converter (TDC) with a dynamic time amplification (DTA) to improve the resolution at low power. The key element of this TDC is the DTA. It samples the residual time errors as voltages held in the MOM capacitors and discharges them to generate the amplified time difference. Thanks to the dynamic time-voltage-time conversion, the DTA realizes high linearity and power efficiency, and can be employed to build a pipeline TDC architecture with high sampling frequency because of its sample and hold operation. Moreover, the DTA maintains constant gain, so only a one-time forground calibration for gain mismatch is required in this TDC. Simulations show that the TDC designed in 65 nm CMOS achieves 8-bit, 1.75 ps of time resolution, and 1 LSB INL and 1.6 LSB DNL with one-time foreground calibration at 400 MHz sampling frequency while just consuming 726 μW power, which corresponds to 18.45 fJ/Conv. FoM.
Yuting Tu, Rongjin Xu, Dawei Ye, Liangjian Lyu, Chuanjin Richard Shi
ISCAS2
2019 A 2.46GHz, -88dBm Sensitivity CMOS Passive Mixer-First Nonlinear Receiver with >50dB Tolerance to In-Band Interferer
abstract
This paper presents a -88 dBm sensitivity, 150Kbp/s OOK mixer-first nonlinear receiver in 65nm CMOS operating at the 2.46GHz ISM band. Since the LNA in the 1stIF band can be saturated by the strong in-band interferer, the shifted limiter (SL) is used to improve the interference resilience. Hence, by using an input power detection block, the 1stgain stage in the 1stIF band can alternatively turn on the LNA or the SL to improve the dynamic range. The in-band SIR at +/-1, 3 and 5MHz are measured to be -43/-11, -53/-54 and -53/-56dB respectively, while just consumes 380 to 610μW.
Dawei Ye, Rongjin Xu, Liangjian Lyu, Chuanjin Richard Shi
ISCAS2