Low-Power High-Accuracy VCO-Based Comparator for Sensor Interface Applications

Esmaeilzadeh, Mahin; Ali, Mohamed; Hassan, Ahmad; Audet, Yves

doi:10.1109/newcas49341.2020.9159801

Cited by 2 publications

(1 citation statement)

References 17 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…However, nonlinear performance and poor phase noise are the key issues in ring VCOs. For instance, the nonlinear nature of voltage-to-time conversion provokes a linearity issue in a time-domain comparator and the VCO phase noise has a great impact on its resolution [8], [21]. Besides, the performance of VCO-based ADCs is severely distortion limited by VCO gain variation (tuning nonlinearity) that causes an inter-stage gain error [22].…”

Section: Introductionmentioning

confidence: 99%

A Low-Phase-Noise CMOS Ring Voltage-Controlled Oscillator Intended for Time-Based Sensor Interfaces

2022

Self Cite

View full text Add to dashboard Cite

We describe in this paper an improved ring voltage-controlled oscillator (VCO) showing a reduced phase noise while allowing an extended frequency tuning range. The phase noise improvement is obtained through the minimized contribution of tuning line noise while maintaining a rail-to-rail swing. The proposed VCO features a linear tuning characteristic yielding a constant gain over a wide range of operating frequencies. An analytical model is extracted resulting in closed-form expressions for the VCO phase noise. Employing the analytical expressions, the contributed noise and phase noise limitations are fully addressed, and all the effective factors are investigated. The VCO prototype was fabricated in a 0.35 µm CMOS process. It consumes 0.903 mW from a 3.3 V supply when running at its maximum oscillation frequency of 9.37 MHz. The measured VCO phase noise is -147.57 dBc/Hz at 1 MHz offset from the 9.37 MHz oscillation frequency, and the circuit occupies a silicon area of 0.005 mm 2 . A state-variable Matlab ® model of a timebased sensor interface has been developed including the impact of phase noise nonideality. The system-level simulations demonstrate that the PLL-based sensor interface exploiting the proposed VCO characteristics can achieve a 88.43 dB signal-to-noise ratio over a 1-kHz bandwidth.

show abstract

Section: Introductionmentioning

confidence: 99%