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This paper presents a novel jitter reduction technique for a voltage-controlled ring oscillator (VCRO). This technique is helpful in employing VCRO-based circuits like Analog to Digital Converter (ADC), Phase Locked Loop (PLL) and time-based circuits whose performance is severely degraded by high jitter. In the proposed technique, the jitter is extracted using Excess Phase Discrimination (EPD) block and is transformed into Pulse Width Modulated (PWM) signal, which is then fed into the Phase Compensator (PC) block. This block reduces the jitter by about half its value after enabling the Single Ended Injection Locking (SEIL). The proposed work is designed in SCL 180 nm CMOS technology at 1.8 V supply. On enabling the proposed circuit, the Root Mean Square (RMS) jitter reduces from 5.94 to 2.58 ps (about 56%) for VCRO running at 58 MHz and consumes a total power of 375.84 μ W. The overall performance of the proposed circuit does not vary much in the post-layout simulations, hence demonstrating the effectiveness of the proposed technique. [ABSTRACT FROM AUTHOR]

A dual‐loop ADPLL architecture with 3‐bit flash TDC and background calibration‐based VCO is presented in this paper. The major aim of this work is to achieve the low jitter, low power, fast locking, and PVT‐insensitive ADPLL using simple flash TDC and gain calibrated VCO. A simple flash‐based 3‐bit TDC in the main loop is used which helps in achieving the fast locking with lower power consumption in ADPLL. The novel low phase noise VCO, with gain calibration in another loop, is used to fasten the locking process and jitter reduction due to any PVT variations. Therefore, both flash TDC and dual loop in the proposed ADPLL architecture help in achieving the fast locking. Proposed ADPLL is designed in SCL 180 nm CMOS technology at 1.8 V. The resolution of 3‐bit flash TDC is 3 ps. The achieved jitter of ADPLL is 1.83 ps with a phase noise of −153 dBc/Hz and locking time of 1.7 μs. Total power consumption is 5.3 mW at a frequency of 1.6 GHz. [ABSTRACT FROM AUTHOR]

In this work, a dual loop all-digital phase locked loop (ADPLL) is designed to obtain a fast locking, low power and low jitter for SoC and battery-operated applications. The high speed and high-resolution 4-bit flash time to digital converter (TDC) is also proposed to achieve low jitter and fast locking in ADPLL. The flash TDC uses a foreground calibration to make the ADPLL work robustly over PVT variations. In present work, fasting settling time of 1 μs and low power is achieved for proposed ADPLL owing to flash-based TDC and dual loop architecture. The proposed 4-bit flash TDC achieves a resolution of 6 ps. A low-phase noise voltage-controlled oscillator based on inverters is designed to obtain a reduced jitter in ADPLL. The ADPLL is implemented in a 180-nm SCL digital CMOS technology. The achieved phase noise of proposed ADPLL is − 128.2 dBc/Hz at an offset of 100 MHz. At an output frequency of 1.6 GHz, the periodic jitter of ADPLL is 7.8 ps, and power consumption is 6.5 mW. [ABSTRACT FROM AUTHOR]

This paper aims at designing a digital approach based low jitter, smaller area and wide frequency range phase locked loop (PLL) to reduce the design efforts and power which can be used in System-on-chip applications for operating frequency in the range of 0.025–1.6 GHz. The low power, scalable and compact charge pump is proposed which reduces the overall power consumption and area of proposed PLL. A frequency phase detector (PFD) based on inverters and tri-state buffers have been proposed for the PLL. It is fast which improves the locking time of PLL. Also, pseudo-differential voltage controlled oscillator (VCO) is designed with CMOS inverter gates. The inverters are used as phase interpolator to maintain the phase difference of 180∘ between two outputs of VCO. Also, the inverters are used as variable capacitors to vary the frequency of proposed VCO with control voltage. It demonstrates the good phase noise performance enabling proposed PLL to have low jitter and wide frequency range. All the major blocks like PFD, charge pump and VCO are designed using digital gate methodology thus saving area and power and also reduce design efforts. Also, these digitally designed blocks enable the PLL to have low jitter small area and wide range. The proposed PLL is designed in a 0.18- μ m CMOS technology with supply voltage of 1.8 V. The output clocks with cycle-to-cycle jitter of 2.13 ps at 1.6 GHz. The phase noise of VCO is − 137 dBc/Hz at an offset of 100 MHz and total power consumed by the proposed PLL is 2.63 mW at 1.6 GHz. [ABSTRACT FROM AUTHOR]

A fast phase frequency detector (PFD) and low gain low phase noise voltage-controlled oscillator (VCO)-based phase-locked loop (PLL) design are presented in this paper. PLL works in the frequency range of 0.025–1.6 GHz, targeting various SoC applications. The proposed PFD, designed using CMOS dynamic logic, is fast and improves the locking time, dead zone and blind zone in the PLL. The standard CMOS inverter gate-based pseudo differential VCO is used in the PLL. Also, CMOS inverter is used as variable capacitor to tune the frequency of VCO with control voltage. The proposed PLL is designed in a 180 nm CMOS process with supply voltage of 1.8 V. The phase noise of VCO is − 1 3 7 dBc/Hz at an offset frequency of 100 MHz. The reference clock of 25 MHz synthesizes the output clock of 1.6 GHz with rms jitter of 0.642 ps. [ABSTRACT FROM AUTHOR]

In the present work, an all digital phase locked loop architecture (ADPLL) employing a bang-bang phase frequency detector (BB-PFD) and the 3-bit flash based time to digital converter (TDC) is designed to enhance the jitter and locking time performance. The proposed ADPLL utilizes a low power and high resolution 3-bit flash TDC with foreground calibration to suppress the issues of process, voltage and temperature (PVT) spreads and achieves low jitter and low power ADPLL. To obtain the fast locking, a proposed dynamic bang-bang PFD is used. The proposed ADPLL takes only 5 iterations to achieve the locking from unlocked state. Additionally, ADPLL employs a wide range and low phase noise voltage controlled oscillator (VCO) based on inverters to obtain a reduced jitter in ADPLL. The proposed ADPLL is designed in 180-nm SCL digital CMOS technology at 1.8 V supply. It consumes a total power of 5.94 mW at 1.8 V. From the post layout simulations, the achieved FoM and periodic jitter is −227.6 dB and 1.71 ps respectively at an output frequency of 1.6 GHz. The achieved phase noise of proposed ADPLL is −131.2 dBc/Hz at offset of 100 MHz. [ABSTRACT FROM AUTHOR]