A purely-VCO-based single-loop high-order continuous-time ΣΔ ADC

This paper reports a voltage-controlled oscillator (VCO)-based single-loop continuous-time (CT) ΣΔ analog-to-digital converter (ADC) that does not need any OTA-based analog integrator. It achieves the second-order noise shaping by cascading two VCO-based integrators and removing the sampling operation in the first VCO-based integrator. Behavioral simulations confirm the validity of the proposed ADC architecture.

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