A 10-Gb/s CMOS clock and data recovery circuit with a half-ratelinear phase detector

A 10-Gb/s phase-locked clock and data recovery circuit incorporates an interpolating voltage-controlled oscillator and a half-rate phase detector. The phase detector provides a linear characteristic while retiming and demultiplexing the data with no systematic phase offset. Fabricated in a 0.18-μm CMOS technology in an area of 1.1×0.9 mm², the circuit exhibits an RMS jitter of 1 ps, a peak-to-peak jitter of 14.5 ps in the recovered clock, and a bit-error rate of 1.28×10^-6, with random data input of length 2²³-1. The power dissipation is 72 mW from a 2.5-V supply     

A 12 Gb/s Si bipolar 4:1-multiplexer IC for SDH systems

The 4:1-multiplexer reported here is based on a 21 GHz f_T 0.4 μm silicon bipolar technology and operates up to 12 Gb/s. For facilitating system applications, the input signals are aligned in phase and retiming of the output signal is provided. A phase control circuit permits the choice of the optimum clock phase for the first and the second multiplexer stages; an internal delay line is not necessary. The 4:1-multiplexer consumes about 1.8 W with a single supply voltage of -4.5 V     

A Low Jitter Programmable Clock Multiplier Based on a Pulse Injection-Locked Oscillator With a Highly-Digital Tuning Loop

This paper introduces a pulse injection-locked oscillator (PILO) that provides low jitter clock multiplication of a clean input reference clock. A mostly-digital feedback circuit provides continuous tuning of the oscillator such that its natural frequency is locked to the injected frequency. The proposed system is demonstrated with a prototype consisting of a custom 0.13 $mu$m integrated circuit with active area of 0.4 mm$^{2}$ and core power of 28.6 mW, along with an FPGA, a discrete DAC and a simple RC filter. Using a low jitter 50 MHz reference input, the PILO prototype generates a 3.2 GHz output with integrated phase noise, reference spur, and estimated deterministic jitter of 130 fs (rms), ${-}$ 63.9 dBc, and 200$~$ fs (peak-to-peak), respectively.      

A 900-Mb/s CMOS data recovery DLL using half-frequency clock

A data recovery delay-locked loop (DILL) for nonreturn-to-zero (NRZ) data transmission is described. A reference clock is delayed for triggering a latch that samples the incoming NRZ data stream. The data rate can be twice the reference clock frequency. The circuit has a proportional nondead-zone sampling phase detector that also serves the role of charge pump. A self-correcting function reduces the problem of the finite phase capture range associated with conventional DLLs. The prototype circuit is fabricated in 2.5-V 0.25-μm CMOS and occupies an area of only 270 × 50 μm². It is demonstrated that at 900-Mb/s NRZ data, jitter is reduced from 118.2- to 31.3-ps rms jitter for a power consumption of only 3 mW     

A 5-Gb/s CDR Circuit With Automatically Calibrated Linear Phase Detector

This paper presents a 5-Gb/s clock and data recovery (CDR) circuit which implements a calibration circuit to correct static phase offsets in a linear phase detector. Static phase offsets directly reduce the performance of CDR circuits as the incoming data is not sampled at the center of the eye. Process nonidealities can cause static phase offsets in linear phase detectors by adversely affecting the circuits in a way which is difficult to design for, making calibration an attractive solution. Both the calibration algorithm and test chip implementation are described and measured results are presented. The CDR circuit was fabricated in a 0.18-mum, six metal layer standard CMOS process. With a pseudorandom bit sequence of 2⁷ - 1 calibration improved the measured bit error rate from 4.6 x 10^-2 to less than 10^-13.     

A 2.5-GHz four-phase clock generator with scalable no-feedback-looparchitecture

An accurate yet simple multiphase clock generator has been developed by using a delay compensation technique based on phase interpolation that supplies a multiphase clock signal without increasing local circuit area. This generator is applied to the 2.5-GHz four-phase clock distribution of a 5-Gb/s×8-channel receiver fabricated with 0.13-μm CMOS technology. The four-phase generator in the receiver consumes 30 mW and occupies only 0.009 mm². It requires only 1.5 clock cycles to produce accurate phase differences and can operate from 1.5 to 2.8 GHz, with a range of phase error within ±5     

A 0.004-mm2 Portable Multiphase Clock Generator Tile for 1.2-GHz RISC Microprocessor

Portable multiphase clock generators capable of adjusting its clock phase according to input clock frequencies have been developed both in a 0.18-mum and in a 0.13-mum CMOS technologies. They consist of a full-digital CMOS circuit design that leads to a simple, robust, and portable IP. In addition, their open-loop architecture lead to no jitter accumulation and one-cycle lock characteristic that enables clock-on-demand circuit structures. The implemented low power clock generator tile in a 0.13-mum CMOS technology occupies only 0.004 mm ² and operates at variable input frequencies ranging from 625 MHz to 1.2 GHz within a plusmn 2% phase error having one-cycle lock time.     

Si bipolar 14 Gb/s 1:4-demultiplexer IC for system applications

A 1:4-demultiplexer IC meeting the essential requirements for lightwave communication systems has been designed based on a 21 GHz f _T 0.4 μm Si bipolar process. The circuit provides features such as bit-rotation control, clock enable control, outputs aligned in time, and phase aligner for clock signals. It operates up to 14 Gb/s (14 GHz) with a phase margin of ⩾250°. The power consumption is 2 W with a -4.5 V supply. 1:16-demultiplexer operation is demonstrated on the basis of 1:4-demultiplexer IC's at 10 Gb/s     

A 10-b 40-MHz 0.8-μm CMOS current-output D/A converter

A 10-b binary-weighted D/A digital-to-analog converter based on current division is presented. The effective resolution bandwidth is 5 MHz at a maximum clock frequency of 40 MHz. The circuit is integrated in a 0.8-μm double-metal CMOS technology and the chip area is 0.4 mm². This particular converter was realized by constructing the bit currents through a careful combination of unit current sources and by limiting the driving voltage on the gates of the current switches     

Precise CMOS current sample/hold circuits using differential clockfeedthrough attenuation techniques

New CMOS current sample/hold (CSH) circuits capable of overcoming the accuracy limitations in conventional circuits without significantly reducing operating speed are proposed and analyzed. A novel differential clock feedthrough attenuation (DCFA) technique is developed to attenuate the signal-dependent clock feedthrough errors. Unlike conventional techniques, the DCFA circuit allows the use of dynamic mirror techniques, and results in no additional finite output resistance errors or device mismatch errors. The test chip of the proposed fully differential CSH circuit with multiple outputs has been fabricated in 1.2-μm CMOS technology. Using a single 5-V power supply, experimental results show that the signal-dependent clock feedthrough error current is less than ±0.4 μA for the input currents from -550 μA to 550 μA. The acquisition time for a 900-μA step transition to 0.1% settling accuracy is 150 ns. For a 410-μA_p-p input at 250 MHz with the fabricated fully-differential CSH circuit clocked at 4 MHz, a total harmonic distortion of -60 dB, and a signal-to-noise ratio of 79 dB have been obtained. The active chip area and power consumption of the fabricated CSH circuit are 0.64 mm² and 20 mW, respectively. Both simulation and experimental results have successfully verified the functions and performance of the proposed CSH circuits     

A CMOS analog timing recovery circuit for PRML detectors

A fully integrated analog timing recovery circuit for partial-response maximum-likelihood (PRML) detectors for digital magnetic storage is described. The circuit uses a decision-directed minimum mean-squared error (MMSE) algorithm and achieves phase acquisition within 100-bit periods at a maximum speed of 180 Mb/s. It dissipates 76 mW from a single 3.3-V supply and has an active die area of 1.8 mm² in a 1.2-μm CMOS process. At 180 Mb/s, the rms clock fitter is 15 ps and peak-to-peak jitter is 97 ps. The test results demonstrate the feasibility of an analog CMOS implementation of decision-directed MMSE timing recovery for PRML detectors     

Fully monolithic integrated 43 Gbit/s clock and data recoverycircuit in InP HEMT technology

A fully monolithic integrated 43 Gbit/s clock and data recovery circuit for optical fibre communication systems is described. The circuit is based on a phase-locked loop technique, and the input data signal is regenerated with the data-rate clock signal. The circuit was fabricated with 0.1 μm gate-length InAlAs/InGaAs/InP HEMTs, and error-free operation was confirmed for 2³¹-1 PRBS data signal at 43 Gbit/s     

A 2.5 Gb/s Run-Length-Tolerant Burst-Mode CDR Based on a 1/8th-Rate Dual Pulse Ring Oscillator

A 2.5 Gb/s burst-mode clock and data recovery (CDR) circuit is presented that uses a 1/8th-rate ring oscillator with two pulses running simultaneously that are phase independent. One “tune” pulse sets the delay of the ring by phase locking it to a reference. The other “clock” pulse tracks the phase of the incoming data by a process of pulse removal and reinsertion. Because both pulses share the same ring, there is no frequency mismatch between the incoming data stream and the recovered clock in frequency synchronous systems, allowing for large data run lengths. A 1:8 data-demux clock is naturally generated by tapping the clock pulse along the ring. Phase acquisition is instantaneous from a single data edge. Run length tolerance is larger than 72 bits. The 0.6 mm$^{2}$ 0.13 $mu$m CMOS chip includes a CML-to-CMOS input buffer, PLL with on-chip loop filter, PRBS checker, 1:8 data demux, and eight output buffers. It has 2.7 ${rm UI}_{rm pp}$ measured jitter tolerance at 100 kHz and consumes 42 mW from a single 1.2 V supply.      

A 1.25–5 GHz Clock Generator With High-Bandwidth Supply-Rejection Using a Regulated-Replica Regulator in 45-nm CMOS

A clock generator for high-speed chip-to-chip link receivers was implemented in a 45-nm CMOS SOI technology. A low sensitivity to supply voltage noise was achieved by means of a low-dropout voltage regulator using a replica feedback in the regulation loop, where the replica resistance is regulated by a second loop. We show that by adjusting the replica load the necessary matching of the $gm/gds$ ratio of the current sources can be achieved. A power supply rejection of $>,$22 dB was measured up to 1 GHz for a circuit operating from a 1 V supply with 80$~$ pF decoupling capacitance and a load current of 18.5 mA. The maximum supply sensitivity of the clock generation circuit (DLL plus phase rotators) was 4.5 ps/100 mV supply noise over the entire noise frequency range at clock frequencies from 1.25–5 GHz. The phase rotator achieves a wide range of operating frequencies by providing programmable rise/fall times in its selection stage. In addition, low voltage operation of the circuit was demonstrated at supply voltages down to 0.7$~$V and a clock frequency of 1.6 GHz.      

Measuring Transistor Large-Signal Noise Figure for Low-Power and Low Phase-Noise Oscillator Design

This paper presents an experimental method for determining additive phase noise of an unmatched transistor in a stable 50-$Omega$ environment. The measured single-sideband phase noise is used to determine the large-signal noise figure of the device. From the Leeson–Cutler formula and a known oscillator circuit with the characterized transistor, the phase noise of the oscillator can be predicted. The method is applied to characterization of several bipolar devices around 3.4 GHz, the frequency of interest for miniature rubidium-based atomic clock voltage-controlled oscillators.      

A 10-Gb/s CMOS CDR and DEMUX IC With a Quarter-Rate Linear Phase Detector

This paper presents a 10-Gb/s clock and data recovery (CDR) and demultiplexer IC in a 0.13-mum CMOS process. The CDR uses a new quarter-rate linear phase detector, a new data recovery circuit, and a four-phase 2.5-GHz LC quadrature voltage-controlled oscillator for both wide phase error pulses and low power consumption. The chip consumes 100 mA from a 1.2-V core supply and 205 mA from a 2.5-V I/O supply including 18 preamplifiers and low voltage differential signal (LVDS) drivers. When 9.95328-Gb/s 2³¹-1 pseudorandom binary sequence is used, the measured bit-error rate is better than 10^-15 and the jitter tolerance is 0.5UIpp, which exceeds the SONET OC-192 standard. The jitter of the recovered clock is 2.1 psrms at a 155.52MHz monitoring clock pin. Multiple bit rates are supported from 9.4 Gb/s to 11.3 Gb/s     

10 GB/s bit-synchronizer circuit with automatic timing alignment byclock phase shifting using quantum-well AlGaAs/GaAs/AlGaAs

A bit-synchronizer circuit is presented which operated up to a bit rate of Gb/s. The circuit comprises two master-slave flip -flops for data sampling, two EXCLUSIVE-OR gates for clock phase adjustment, an active signal splitter, and an EXCLUSIVE-OR gate for data transition detection. The gain of the EXCLUSIVE-OR phase comparator circuit is measured to be 302 mV/rad for a 1010-bit sequence. The margins for monotonous phase comparison are ±54° relative to the `in bit cell center' position of the sampling clock edge. The circuit is fabricated by using an enhancement/depletion 0.3 μm recessed-gate AlGaAs/GaAs/AlGaAs quantum-well FET process. The chip has a power dissipation of 230 mW at a supply voltage of 1.90 V     

A monolithic 156 Mb/s clock and data recovery PLL circuit using thesample-and-hold technique

The PLL circuit described here performs the function of data and clock recovery for random data patterns by using a sample-and-hold technique, and four component circuits (a phase comparator, a delay circuit, a voltage-controlled oscillator, and a S/H switch with a low-pass-filter) were specially designed to further stabilize the PLL operation. A test chip fabricated using Si bipolar process technology demonstrated error-free operation with an input of 2²³-1 PRBS data at 156 Mb/s. The rms data pattern jitter was reduced to only 1.2 degrees with only an external power supply bypass capacitor     

Clock multiplier using digital CMOS standard cells for high-speeddigital communication systems

The authors propose and evaluate the performance of a 2^N times clock multiplier that controls memory components for high-speed data communications. To improve the reliability of the circuit, a symmetric circuit structure is used, while to verify circuit operation by means of a simple method, an MVU estimator is found from simulation data. The proposed circuit can provide clock rates, which are usually required in the multiple phase shift keying (MPSK) or multiple quadrature amplitude modulation (MQAM) modulation schemes, of 2 to 2^N times that of the input clock     

New proposal for a multigigabit/s clock recovery IC based on a standard silicon bipolar technology

A clock recovery IC for optical fibre communication at multigigabit/s is proposed. The clock frequency extracted corresponds to half the bit rate. The 2:1 frequency division is carried out by a double balanced mixer and the frequency selection by an SAW filter. Circuit simulations are based on a standard 2 ?m silicon bipolar technology. The circuit was optimisd at 3.4 Gbit/s for a power consumption of 220 mW with a 1.7 GHz SAW filter (Q = 340). The dynamic clock phase jitter, estimated from circuit simulations, is less than 0.5°. Circuit simulations predict that the operating bit rate may be exended up to 4.5 Gbit/s.