Computing Timing Jitter From Phase Noise Spectra for Oscillators and Phase-Locked Loops With White and$1/f$Noise

Phase noise and timing jitter in oscillators and phase-locked loops (PLLs) are of major concern in wireless and optical communications. In this paper, a unified analysis of the relationships between time-domain jitter and various spectral characterizations of phase noise is first presented. Several notions of phase noise spectra are considered, in particular, the power-spectral density (PSD) of the excess phase noise, the PSD of the signal generated by a noisy oscillator/PLL, and the so-called single-sideband (SSB) phase noise spectrum. We investigate the origins of these phase noise spectra and discuss their mathematical soundness. A simple equation relating the variance of timing jitter to the phase noise spectrum is derived and its mathematical validity is analyzed. Then, practical results on computing jitter from spectral phase noise characteristics for oscillators and PLLs with both white (thermal, shot) and$bf 1/f$noise are presented. We are able to obtain analytical timing jitter results for free-running oscillators and first-order PLLs. A numerical procedure is used for higher order PLLs. The phase noise spectrum needed for computing jitter may be obtained from analytical phase noise models, oscillator or PLL noise analysis in a circuit simulator, or from actual measurements.     

A low-voltage low-power programmable fractional PLL in 0.18-μm CMOS process

The prolific growth of portable electronic devices (PED) has generated tremendous interests among researchers to develop programmable phase-locked loops (PLLs) because of their abilities to produce multiple spectrally pure output frequencies from a fixed frequency oscillator. The power consumption of the RF block of a PED is mostly dominated by the programmable PLLs which are widely used in the design of these devices. Therefore to reduce the overall power consumption in a portable device and to increase the battery life time, low-voltage and low-power are the two key requirements for the PLL design. In this work an improved programmable fractional frequency divider has been incorporated to enhance the overall performance of the PLL that includes lower operating supply voltage and lower power consumption compared to the state-of-art. The proposed programmable fractional PLL has an operating frequency in the range of 1.7–2.5 GHz, and a frequency resolution of 2.5 MHz. Measurement results reveal that the proposed programmable PLL can operate at 2.4 GHz with a 1.46 V power supply voltage and only 10 mW of power consumption.     

Low-jitter PLL based on symmetric phase-frequency detector technique

A low-jitter phase-locked loop (PLL) with a symmetric phase frequency detector has been proposed. The phase-frequency detector is composed of only two symmetric XOR gates. The voltage-controlled oscillator within the PLL consists of four-stage ring oscillators which are coupled to each other and oscillate with the same frequency and a phase shift of 45 degrees. The PLL was fabricated in a 0.18 μm CMOS technology. Measured phase noise of the PLL output at 500 kHz offset from the 5 GHz center frequency is −102.6 dBc/Hz. The circuit exhibits a low rms jitter of 2.06 ps and a capture range of 280 MHz. The power dissipation excluding the output buffers is only 21.6 mW from a 1.8 V supply.     

Digital fast acquisition method for phase-lock loops

A method for enhancing the frequency-acquisition performance of phase-lock loops (PLLs) is presented, which can be used in all PLLs that employ sequential phase detectors. The proposed method always forces the PLL into the phase-acquisition mode by realising a phase detector transfer characteristic with a pseudolinear infinite phase range. Especially in the case of charge-pump PLLs the proposed method is very useful. Practical results show that the acquisition performance can increase by nearly two orders of magnitude     

Design of loop filter in phase-locked loops

An exact method for designing loop filters in third-order PLLs is presented. The method is simple and results in a PLL with superior loop dynamics and improved output jitter while maintaining the same loop bandwidth compared to that of a PLL designed using the conventional approach. The method is readily applicable to higher order PLLs     

Fast timing recovery for linearly and nonlinearly modulated systems

Digital phase lock loops (PLLs) are often used in timing acquisition systems. It is known that some non-data-aided timing error detectors occasionally cause hangup problems in digital PLLs. In this paper, we introduce a novel two step antihangup timing recovery scheme. Through intensive simulations, we show that this enhanced scheme greatly reduces the probability of hangup, and speeds up the timing recovery process for both linearly and nonlinearly modulated systems.     

Noise-Insensitive Digital BIST for any PLL or DLL

PLLs are the heart of most SoCs, so their performance affects many tests. Practical, published PLL BIST approaches cannot measure <10 ps RMS jitter or >1 GHz. This paper describes how a SerDes undersampling DFT technique was adapted to test multiple PLLs and DLLs for jitter, phase error, output frequency, duty cycle, lock time, and lock range. Two techniques for cancelling random and systematic noise are also described. The multi-GHz range, sub-picosecond jitter noise floor, and minimal silicon area are better than for any previous silicon-proven DFT or BIST that needs no calibration or analog circuitry. FPGA implementation results are provided.

Fast acquisition clock and data recovery circuit with low jitter

This paper presents a half-rate clock and data recovery circuit (CDR)that combines the fast acquisition of a phase selection (PS) delay-locked loop (DLL) with the low jitter of a phase-locked loop (PLL). The PLL acquisition time improves considerably with use of a phase frequency magnitude detector(PFMD) that feeds back an estimate of the magnitude of the frequency difference in addition to the sign. Measurements in 0.5/spl mu/m CMOS technology show operation up to 700 Mb/s, a 7% acquisition range, an initial acquisition time of 8 bit times with jitter of 30% bit time, and jitter of 16 ps after the PLL acquires lock. With a phase frequency detector (PFD), the PLL locks in about 700 ns from an initial frequency difference of 7%. Measurements using a PFMD show the 700 ns PLL acquisition time is reduced on average by about a factor of 5 to 140 ns from an initial 7% frequency difference. The power dissipation is 300mW.     

An Analytical Approximation for the Pull‐Out Frequency of a PLL Employing a Sinusoidal Phase Detector

The pull‐out frequency of a second‐order phase lock loop (PLL) is an important parameter that quantifies the loop's ability to stay frequency locked under abrupt changes in the reference input frequency. In most cases, this must be determined numerically or approximated using asymptotic techniques, both of which require special knowledge, skills, and tools. An approximating formula is derived analytically for computing the pull‐out frequency for a second‐order Type II PLL that employs a sinusoidal characteristic phase detector. The pull‐out frequency of such PLLs can be easily approximated to satisfactory accuracy with this formula using a modern scientific calculator.     

A 200-MHz CMOS phase-locked loop with dual phase detectors

A high-frequency integrated CMOS phase-locked loop (PLL) including two phase detectors is presented. The design integrates a voltage-controlled oscillator, a multiplying phase detector, a phase-frequency detector, and associated circuitry on a single die. The loop filter is external for flexibility and can be a simple passive circuit. A 2-μm CMOS p-well process was used to fabricate the circuit. The loop can lock on input frequencies in excess of 200 MHz with either or both detectors and consumes 500 mW from a single 5-V supply. The oscillator is a ring of three inverting amplifiers and draws from an internal supply voltage regulated by an on-chip bandgap reference. This combination serves to reduce the supply and temperature sensitivity is less than 5%/V, and the oscillator temperature variation is 2.2% in the range of 25 to 80°C. The typical oscillator tuning range is 112 to 209 MHz. The multiplying phase detector and phase-frequency detector exhibit input-referred phase offsets of <4° and -24°, respectively. A numerical system simulation program was written to explore the time-domain behavior of an idealized model based on the PLL design     

Double-frequency jitter figures in master–slave PLL networks

The main strategy used for distributing clock information in synchronous telecommunication networks is the master–slave. A particular node (master) provides the precise clock signals that are sent to the other nodes (slaves), which recover phase and frequency information by using phase-locked loops (PLLs). In spite of PLLs being equipped with low-pass filters, the recovered clock signals always contain second harmonic components that appear as a deterministic component of the whole phase jitter. Here, we study how the amplitude of this double-frequency jitter depends on the PLL parameters and delays. Chain and star topologies are considered with slave PLLs equipped with the most usual types of first-order low-pass filter. For both topologies, numerical simulations show that this kind of jitter depends on the position of the node in the chain or star being slightly dependent on the number of nodes.     

Frequency Detectors for PLL Acquisition in Timing and Carrier Recovery

A significant problem in phase-locked loop (PLL) timing and carrier extraction is the initial acquisition. Very narrow loop bandwidths are generally required to control phase jitter, and acquisition may depend on an extremely accurate initial VCO frequency (VCXO) or sweeping. We describe two simply implemented frequency detectors which, when added to the traditional phase detector, can effect acquisition even with very small loop bandwidths and large initial frequency offsets. The first is the quadricorrelator, previously applied to timing recovery by Bellisio, while the second is new, and called a rotational frequency detector. The latter, while limited to lower frequencies and higher signal-to-noise ratios, is suitable for many applications and can be implemented with simpler circuitry.     

一个简单鉴频鉴相器结构实现的快速锁定低抖动锁相环

用简单的鉴频鉴相器结构实现了一个快锁定低抖动的锁相环.鉴频鉴相器仅仅由两个异或门组成,它可以同时获得低抖动和快锁定的性能.锁相环中的电压控制振荡器由四级环形振荡器来实现,每级单元电路工作在相同的频率,并提供45°的相移.芯片用0.18μm CMOS工艺来实现.PLL输出的中心频率为5GHz,在偏离中心频率500kHz处,测量的相位噪声为-102.6dBc/Hz.锁相环的捕获范围为280MHz,RMS抖动为2.06ps.电源电压为1.8V时,功耗仅为21.6mW(不包括输出缓冲).     

Lock detection in Costas loops

Previous analyses of lock detector algorithms for Costas loops have ignored the effects of the inherent correlation between samples of the phase error process. In this work, analysis and simulations are used to quantify the effects of phase correlation on lock detection for the `square law' and `absolute value' type detectors. Results which depict the lock detection probability as a function of loop signal-to-noise ratio for a given false alarm rate are obtained. It is shown that the square law detector experiences less degradation due to phase jitter than the absolute value detector and that the degradation in detector signal-to-noise ratio is more pronounced for squarewave than for sinewave signals     

Frequency detector for fast frequency lock of digital PLLs

A new frequency detector, which allows for a fast frequency lock of phase-locked loops (PLLs), is presented. It uses the feedback divider that already exists in a PLL to determine the frequency difference. The proposed frequency detector provides frequency difference information at each reference cycle, and thus guarantees fast frequency acquisition     

Jitter Analysis and a Benchmarking Figure-of-Merit for Phase-Locked Loops

This brief analyzes the jitter as well as the power dissipation of phase-locked loops (PLLs). It aims at defining a benchmark figure-of-merit (FOM) that is compatible with the well-known FOM for oscillators but now extended to an entire PLL. The phase noise that is generated by the thermal noise in the oscillator and loop components is calculated. The power dissipation is estimated, focusing on the required dynamic power. The absolute PLL output jitter is calculated, and the optimum PLL bandwidth that gives minimum jitter is derived. It is shown that, with a steep enough input reference clock, this minimum jitter is independent of the reference frequency and output frequency for a given PLL power budget. Based on these insights, a benchmark FOM for PLL designs is proposed.      

一款通过抗辐照设计加固技术实现的抗单粒子锁相环

本文设计了一款抗辐照设计加固的锁相环。通过增加一个由锁定探测电路、两个运放和4个MOS器件组成的电荷补偿电路,该锁相环显著地减小了单粒子瞬态引起失锁后系统的恢复时间。许多传统的加固方法主要是致力于提高电荷泵输出结点对单粒子瞬态的免疫力,本文的加固方法不仅能够降低电荷泵输出结点对单粒子瞬态的敏感性,而且也降低了其他模块对单粒子瞬态的敏感性。本文还提出了一种新的描述锁相环对单粒子顺态敏感性的系统模型,基于该模型比较了传统的和加固的锁相环对单粒子瞬态的免疫能力。通过Sentaurus TCAD 仿真平台模拟了单粒子瞬态引起的电流脉冲,用于电路仿真。基于130 nm CMOS 工艺设计了两个锁相环电路,晶体管级的仿真表明本文提出的抗单粒子加固锁相环的恢复时间比传统的锁相环提高了94.3%,同时,电荷补偿电路没有增加系统参数设计的复杂性。     

An integrated 10 GHz low-noise phase-locked loop with improved PVT tolerance

An integrated phase-locked loop (PLL) with low phase noise is presented, which is robust with respect to variations of device parameters with process, supply voltage, and temperature (PVT). The low-noise CMOS voltage-controlled oscillator (VCO) employs two varactors for fine and coarse tuning. By using a CMOS charge pump with output biasing, the dc fine tuning voltage of the VCO and the loop dynamics of the PLL are well defined and fairly independent of PVT variations. Device noise in the charge pump and linearity of the phase detector are much improved by a two-transistor charge pump architecture for fine tuning. We measured a phase noise below −131 dBc/Hz at 10 MHz offset and below −94 dBc/Hz at 10 kHz offset over a tuning range of 1.2 GHz. An integrated phase error below 0.6° was measured, corresponding to an rms jitter below 160 fs. The chip was produced in a 0.25 μm low-cost SiGe BiCMOS technology, occupies a chip area of 2.25 mm² and draws 60 mA from a 3 V supply.     

A PLL based 12 GHz LO generator with digital phase control in 90 nm CMOS

A 12 GHz PLL with digital output phase control has been implemented in a 90 nm CMOS process. It is intended for LO signal generation in integrated phased array transceivers. Locally placed PLLs eliminate the need of long high frequency LO routing to each transceiver in a phased array circuit. Routing losses are thereby reduced and the design of integrated phased array transceivers becomes more modular. A chip was manufactured, featuring two separate fully integrated PLLs operating at 12 GHz, with a common 1.5 GHz reference. The chip, including pads, measures 1050 × 700 μm². Each PLL consumes 15 mA from a 1.2 V supply, with a typical measured phase noise of −110 dBc/Hz at 1 MHz offset. The phase control range exceeds 360°.     

Design challenges of a 65 nm CMOS stacked folded differential PA structure for mobile communications

In this paper, a novel phase-locked loop (PLL) architecture with multiple charge pumps, which is used to design a fast-locking PLL and a low-phase-noise PLL, is proposed. The effective capacitance and resistance of the loop filter in terms of voltage is scaled up/down according to the locking status by controlling the magnitude and direction of the charge pump current. Two PLLs, one with a fast-locking characteristic and the other with a low-phase-noise characteristic, are designed and fabricated in a 0.35-μm CMOS process based on the proposed architecture. The fast-locking PLL has a locking time of less than 6 μs and a phase noise of −90.45 dBc/Hz at 1 MHz offset. The low-phase-noise PLL has a locking time of 25 μs, a phase noise of −105.37 dBc/Hz at 1 MHz offset, and a reference spur of −50 dBc. Both PLLs have an 851.2 MHz output frequency.