Faculty Publications
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Publications by NITK Faculty
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Item A Dead-Zone-Free Zero Blind-Zone High-Speed Phase Frequency Detector for Charge-Pump PLL(Birkhauser, 2020) Lad, H.; Rekha, S.; Laxminidhi, T.This paper presents a novel architecture for phase frequency detector (PFD) which eliminates the blind zone effect as well as the dead zone for a charge-pump phase-locked loop (CP-PLL). This PFD is designed in 65 nm CMOS technology, and its functionality is verified across process, voltage and temperature variations. Achieved maximum frequency of operation (Fmax) is 3.44 GHz which is suitable for high reference clocked fast settling PLLs. Proposed PFD consumes 324 ? W power from 1.2 V supply at maximum operating frequency. The area occupied by proposed circuit layout is 322.612 ? m 2. © 2020, Springer Science+Business Media, LLC, part of Springer Nature.Item Low mismatch high-speed charge pump for high bandwidth phase locked loops(Elsevier Ltd, 2021) Lad Kirankumar, H.; Rekha, S.; Laxminidhi, T.This paper presents a low mismatch high-speed charge pump for high bandwidth phase locked loop (PLL). A novel mismatch compensation technique is used for reducing the current mismatch without having any extra area and power overhead. Proposed circuit is designed for 100 ?A charge pump current (ICP) and it achieves less than 1% mismatch current across all process corners for an output voltage compliance range of 0.2–1 V. A prototype circuit of 1 GHz PLL is designed in 65 nm CMOS technology for testing the proposed charge pump. It achieves ?81.2 dBc spur-level at reference frequency of 250 MHz. In locked condition of the PLL, proposed charge pump consumes 176 ?W power from 1.2 V supply including the reference current. Area occupied by proposed design is 72 × 35 ?m2. © 2021 Elsevier LtdItem Low Power, High Speed, Inductor-less Cascaded Charge Pump Phase Locked Loop(Birkhauser, 2025) Kirankumar, H.L.; Rekha, S.; Laxminidhi, T.A wide frequency range, inductor-less, charge pump phase locked loop (CP-PLL) is presented in this paper. It has a multi-phase, two stage cascaded architecture. This design uses a dead-zone free, zero blind-zone phase frequency detector (PFD) and a low mismatch charge pump (CP) circuit to generate low jitter clocks. A 3-stage single ended ring oscillator of 625 MHz VCO is designed for the first stage. An 8-phase feed-forward coupled VCO with programmable multi band ranging from 1.25 to 5 GHz is designed for the second stage of this cascaded system. Overall, this proposed cascaded PLL achieves jitter FOM and jitter-N FOM of -227.1 and ? 250.1 dB, respectively for 5 GHz output frequency with 1.44 ps rms jitter while consuming 9.24 mW of power from 1.2 V supply. This proposed clock generator circuit, designed in UMC 65 nm CMOS technology, occupies an area of 0.079 mm2. This study contributes to the development of energy-efficient, high speed clock generation solutions derived from a low reference clock. © The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature 2025.
