An OTA-Less Second-Order VCO-Based CT $\Delta\Sigma$ Modulator Using an Inherent Passive Integrator and Capacitive Feedback.

Voltage-controlled oscillator (VCO)-based continuous-time ΔΣ modulators (CTDSMs) are deemed attractive for deep-scaled process. However, to realize high-order noise shaping, existing works still employ operational transconductance amplifiers (OTAs), which limits the benefits brought by the VCO. This article presents an OTA-less second-order VCO-based CTDSM featuring a hybrid passive-VCO architectu...