Single-Loop Delta-Sigma ADC Using Noise-Coupled VCO Quantizer

A single-loop two-step 3 rd order order $\Delta\Sigma$ ADC with voltage-controlled-oscillator (VCO) quantizer employing noise coupling technique is presented. The noise-coupling technique improves the order of noise-shaping by one or more in VCO quantizer, and makes it power efficient. Third-order noise shaping has been achieved with only one active integrator, and the required output swing, gain and bandwidth requirements for the integrator are relaxed. The digital noise-canceling filter is simplified in the proposed architecture, and the specifications of the dynamic element matching are relaxed. Simulation results verify the effectiveness of the proposed structure.