A Cryo-CMOS PLL for Quantum Computing Applications

This article presents the first cryogenic phase-locked loop (PLL) operating at 4.2 K. The PLL is designed for the control system of scalable quantum computers. The specifications of PLL are derived from the required control fidelity for a single-qubit operation. By considering the benefits and challenges of cryogenic operation, a dedicated...

A Low-Jitter and Low-Spur Charge-Sampling PLL

This article presents a low-jitter and low-spur charge-sampling phase-locked loop (CSPLL). A charge-domain sub-sampling phase detector is introduced to achieve a high phase-detection gain and to reduce the PLL in-band phase noise. Even without employing any power-hungry isolation buffers, the proposed phase detector dramatically suppresses...

A Fractional-N Digitally Intensive PLL Achieving 428-fs Jitter and <-54-dBc Spurs Under 50-mV _ppSupply Ripple

In this article, we present a 4.5-5.1-GHz fractional-N digitally intensive phase-locked loop (DPLL) capable of maintaining its performance in face of a large supply ripple, thus enabling a direct connection to a switched-mode dc-dc converter. Supply pushing of its inductor-capacitor (LC) oscillator is suppressed by properly replicating the...

A Cryo-CMOS Oscillator With an Automatic Common-Mode Resonance Calibration for Quantum Computing Applications

This article presents a 4-to-5GHz LC oscillator operating at 4.2K for quantum computing applications. The phase noise (PN) specification of the oscillator is derived based on the control fidelity for a single-qubit operation. To reveal the substantial gap between the theoretical predictions and measurement results at cryogenic temperatures, a...

A 3V 15b 157W Cryo-CMOS DAC for Multiplexed Spin-Qubit Biasing

This paper presents a 15b cryo-CMOS DAC for multiplexed spin-qubit biasing implemented in a 22-nm FinFET process. The integrating-DAC architecture and the robust digitally-assisted high-voltage output stage enable a low power dissipation (157W) and small area (0.08mm2) independent of the number of biased qubits, and a 3V output range well...

A 2.6-to-4.1GHz Fractional-N Digital PLL Based on a Time-Mode Arithmetic Unit Achieving -249.4dB FoM and -59dBc Fractional Spurs

In a fractional-N PLL, it is beneficial to minimize the input range of its phase detector (PD) as it promotes better linearity and higher PD gain for suppressing noise contributions of the following loop components. This can be done by canceling the predicted instantaneous time offset between the frequency reference (FREF) and the variable...

A 0.049mm2 7.1-to-16.8GHz Dual-Core Triple-Mode VCO Achieving 200dB FoMA in 22nm FinFET

LC VCOs with low phase noise (PN) and an octave frequency-tuning range (FTR) are required for multistandard communication devices, software-defined radios, and wireline data links. A viable popular approach is to exploit multicore mode-switching VCOs for two reasons: (1) their PN improves linearly by in-phase coupling of N identical VCOs; (2)...

A 200dB FoM 4-to-5GHz Cryogenic Oscillator with an Automatic Common-Mode Resonance Calibration for Quantum Computing Applications

Low-power, low phase noise (PN) cryogenic frequency generation is required for the control electronics of quantum computers. To avoid limiting the performance of quantum bits, the frequency noise of a PLL should be &lt; 1.9 kHz rms [1]. However, it is challenging for RF oscillators, as the heart of frequency synthesizers to satisfy such a...

A 10-to-12 GHz 5 mW Charge-Sampling PLL Achieving 50 fsec RMS Jitter,-258.9 dB FOM and-65 dBc Reference Spur

This paper presents a charge-sampling PLL (CSPLL), that demonstrates the best reported jitter-power FOM of-258.9 dB thanks to its high phase-detection gain and to the removal of the power-hungry buffer driving the phase detector. It also achieves-65 dBc of reference spur by both minimizing the modulated capacitance seen by the VCO tank and...