Implementation of a VCO-based ADC on TSMC CMOS 65nm for Audio Applications

The high demand for the audio interface on modern System-on-Chips (SoCs) leads to the requirements for Analog-to-Digital Converters (ADCs) in the audible frequency range. To be integrated into SoCs, the ADC should be effortless, compact, and has low power consumption. The Voltage-Controlled Oscillator ADC (VCO-ADC) is digital friendly so it possesses the minimal effort of the digital implementation. Moreover, the VCO-ADC presents adequate signal quality and low dissipated energy at low rail-to-rail voltage. In this paper, an audio VCO-ADC is implemented on the TSMC CMOS 65nm technology. The structure of second-order delta-sigma modulation is chosen to build the audio VCO-ADC. The design includes circuit approaches to work at the main supply of 1.2 V. Finally, the ADC reaches the acceptable signal-to-noise and distortion ratio of 72 \(dB_A\) and consumes a power of 125.2 \(\mu W\) .