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High-speed PLL is highly demanding with the advancement in the VLSI market. PLL performance gets affected due to bandwidth limitation. This paper presents third-order configurable transconductance capacitance ( G m - C)-based loop filter for high-speed PLL. Operational transconductance amplifier (OTA) serves as a basic cell of the G m - C filter. Quasi-floating gate (QFG) and Bulk-driven qausi-floating gate (BD-QFG) MOS-based differential input folded cascode (FC) OTAs are proposed for low-voltage operation. Here, DC gain of the BD-QFG FC OTA enhanced 5.18% than QFG FC OTA. The proposed OTAs enhanced DC gain, CMRR, UGB and FOM along with reduction in the power consumption in comparison to the state-of-art work. Further, third-order G m - C filters are designed using both QFG and BD-QFG MOS-based OTAs and achieved − 3 dB cut-off frequency of 16.51 MHz and 17.22 MHz, respectively. The proposed QFG and BD-QFG MOS-based filters achieved 22.42% and 21.53% reduction in power than the reported result, respectively. The locking time of integer-N PLL is calculated as 0.33 μ s and 0.32 μ s, respectively, through an analytical approach. The transistor-level simulation has been done in 0.18 μ m CMOS process. [ABSTRACT FROM AUTHOR]

This paper deals with the designing of low-power transconductance–capacitance-based loop filter. The folded cascode-based operational transconductance amplifier (OTA) is designed in this paper with the help of quasi-floating bulk MOSFET that achieved the DC gain of 88.61 dB, unity gain frequency of 97.86 MHz and power consumption of 430.62 μ W. The proposed OTA is compared with the exiting OTA structure which showed 19.50% increase in DC gain and 15.11% reduction in power consumption. Further, the proposed OTA is used for the designing of transconductance–capacitance-based loop filter that has been operated at − 3 dB cut-off frequency of 30.12 MHz with the power consumption of 860.90 μ W at the supply voltage of ± 1. 5 V. The transistor-level simulation has been done in 0.18 μ m CMOS process. [ABSTRACT FROM AUTHOR]