Half-rate Linear Phase Detector Research Articles

Referenceless single‐loop CDR with a half‐rate linear PD and frequency acquisition technique

A referenceless single-loop clock and data recovery (CDR) circuit with a half-rate linear phase detector (PD) and an inherent frequency acquisition technique are introduced. Cycle-slip in the half-rate linear PD and its relationship with the frequency acquisition are described in detail. The single-loop CDR consists of a conventional phase-tracking loop and a frequency-tracking unit, referred to as the cycle-slip detector. The proposed CDR is fabricated in a 28 nm CMOS process and achieves a wide capture range of 2.6 Gb/s for a PRBS31 pattern. The RMS and peak-to-peak jitter of the recovered clock are and , respectively, at 8 Gb/s. The high frequency jitter tolerance is measured as . The CDR occupies and consumes 26 mW at 8 Gb/s from a 1.0 V supply.

A 1.62–5.4-Gb/s Receiver for DisplayPort Version 1.2a With Adaptive Equalization and Referenceless Frequency Acquisition Techniques

We present a 1.62–5.4-Gb/s receiver for DisplayPort version 1.2a and propose an adaptive equalizer (EQ) with a peak-level comparison technique for eye measurement. A single comparator and an up/down unmatched-current charge pump are used to realize a simpler EQ architecture with low power dissipation. A referenceless frequency acquisition technique is also proposed. A time-to-digital converter-based pulsewidth detector supports the referenceless frequency acquisition within the range of 1.62–5.4 Gb/s. An XOR-gate-embedded charge pump and a half-rate linear phase detector were used to improve the jitter tolerance (JTOL) performance. The measured eye opening of the proposed EQ at 5.4 Gb/s was 0.68 UI with a −20-dB loss channel. The proposed receiver passed all the JTOL tests of the DisplayPort compliance specification version 1.2b. The power consumption of the receiver was 36.8 mW at 5.4 Gb/s. The receiver occupied a core area of 0.265 mm2 using 65-nm CMOS process technology.

A 400 Mb/s∼2.5 Gb/s Referenceless CDR IC Using Intrinsic Frequency Detection Capability of Half-Rate Linear Phase Detector

A 400 Mb/s∼2.5 Gb/s referenceless clock and data recovery (CDR) IC is presented. This paper shows that the half-rate linear phase detector (PD) has not only phase detection capability but also single-sided frequency detection capability in itself. By using this intrinsic frequency detection capability of the half-rate linear PD, a CDR can be implemented in the single loop architecture without both an external reference clock and a separate frequency detector. For verification, a prototype CDR IC was fabricated in a 0.13 $\mu\text{m}$ CMOS process. With 2.5 Gb/s, $2^{31} - 1$ pseudorandom binary sequence (PRBS), the measurement results show that the frequency acquisition time is 17 $\mu\text{s}$ , the bit error rate (BER) is better than 10−12, the jitter of the recovered clock is 8.6 $\text{ps}_{\mathrm{rms}}$ and the out-of-band jitter tolerance is 0.32 $\text{UI}_{\mathrm{pp}}$ .

1–5.6 Gb/s CMOS clock and data recovery IC with a static phase offset compensated linear phase detector

This study presents a 1–5.6 Gb/s CMOS clock and data recovery (CDR) integrated circuit (IC) implemented in a 0.13 μm CMOS process. The CDR uses a half-rate linear phase detector (PD) of which static phase offset is compensated by an additional binary PD and a digital charge pump (CP) calibration block. During initialisation, the static phase offset is detected by the binary PD and the CP current is controlled accordingly to compensate the static phase offset. Also, the architecture of this CDR IC is designed for a clock embedded serial data interface which transfers CDR training clock patterns before normal random data signals. The implemented IC consumes 16–22 mA from a 1.2 V core supply for data rates of 1–5.6 Gb/s and 20 mA from a 3.3 V I/O supply for two preamplifiers and low-voltage differential signalling drivers. When the 231–1 pseudorandom binary sequence is used, the measured bit-error rate is better than 10–12 and the jitter tolerance is 0.3UIpp. The recovered clock jitter is 21.6 and 4.2 psrms for 1 and 5.6 Gb/s data rates, respectively.

A 5.4-Gb/s Clock and Data Recovery Circuit Using Seamless Loop Transition Scheme With Minimal Phase Noise Degradation

This paper presents a 5.4-Gb/s clock and data recovery circuit using a seamless loop transition scheme which has minimal phase noise degradation. The proposed scheme enables the CDR circuit to change the operation mode without output phase noise degradation or stability problems. A modified half-rate linear phase detector reduces the phase error between the data and clock. A tested chip is manufactured using 0.13-μm CMOS technology. The rms jitter of the proposed CDR circuit is 5.98 ps-rms, which is 2.61 ps lower than the CDR circuit with the conventional scheme. The measured power dissipation is 138 mW with output drivers and an embedded 2:1 MUX at 5.4-Gb/s data rate.

InP DHBT-Based Monolithically Integrated CDR/DEMUX IC Operating at 80 Gbit/s

In this paper, a monolithically integrated clock and data recovery (CDR) circuit with 1:2 demultiplexer (DEMUX), which is intended for use in 80 Gbit/s optical fiber links, is presented. The integrated circuit (IC) is manufactured using an in-house InP double heterostructure bipolar transistor (DHBT) technology, exhibiting cut-off frequency values of more than 220 GHz for both fT and fmax. The CDR circuit in the topology of a phase-locked loop (PLL) is mainly composed of a half-rate linear phase detector including a 1:2 demultiplexer (DEMUX), a loop filter, and a voltage-controlled oscillator (VCO). Hence, the corresponding architecture of each of these components as well as the applied circuit design technique are extensively addressed. Concerning the performance achieved by the CDR/DEMUX IC, the recovered and demultiplexed 40 Gbit/s data from an 80 Gbit/s input signal feature clear eye opening with a signal swing as high as 600 mVpp. The extracted 40 GHz clock signal shows a phase noise as low as -98 dBc/Hz at 100 kHz offset frequency. The corresponding rms jitter amounts to 0.37 ps while the peak-to-peak jitter is as low as 1.66 ps. At a single supply voltage of -4.8 V, the power consumption of the full CDR/DEMUX IC amounts to 1.65 W. To the authors' best knowledge, this work demonstrates the first CDR circuit at the achieved data rate, regardless of all the competing semiconductor technologies

A 10-Gb/s CMOS clock and data recovery circuit with a half-rate linear 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-/spl mu/m CMOS technology in an area of 1.1/spl times/0.9 mm/sup 2/, 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/spl times/10/sup -6/, with random data input of length 2/sup 23/-1. The power dissipation is 72 mW from a 2.5-V supply.