Tsinghua Science and Technology


Voltage-Controlled Oscillator (VCO), Analog-to-Digital Converter (ADC), oversampling (ΔΣ) ADC, time-domain signal processing, VCO-based ΔΣ ADC


The benefits of technology scaling have fueled interest in realizing time-domain oversampling (Δ⁢Σ) of Analog-to-Digital Converters (ADCs). Voltage-Controlled Oscillators (VCO) are increasingly used to design Δ⁢Σ ADCs because of their simplicity, high digitization, and low-voltage tolerance, making them a promising candidate to replace the classical Operational Transconductance Amplifier (OTA) in Δ⁢Σ ADC design. This work aims to provide a summary of the fully VCO-based Δ⁢Σ ADCs that are highly digital and scaling-friendly. This work presents a review of first-order and high-order VCO-based Δ⁢Σ ADCs with several techniques and architectures to mitigate the nonidealities introduced by VCO, achieving outstanding power efficiency. The contributions and drawbacks of these techniques and architectures are also discussed.