DESIGN OF A MIXED SIGNAL VCO BASED ADC FOR HIGH SPEED APPLICATIONS

Abstract: This paper demonstrates a power-efficient implementation of a mixed-signal Analog-to-Digital Converter (ADC) based on a Voltage-Controlled Oscillator (VCO). Conventional Flash ADCs face significant limitations in power and area at multi-GS/s speeds as comparator counts grow exponentially. The proposed hybrid Flash-VCO architecture overcomes these challenges by shifting fine quantization into the time domain. A current-starved ring oscillator scheme is employed for the VCO to achieve high efficiency and CMOS scalability. Simulation results confirm that this approach reduces power consumption and mismatch sensitivity, making it suitable for high-speed, low-resolution biomedical and wireless applications.

Keywords: Voltage-Controlled Oscillator (VCO), Flash ADC, Mixed-Signal Design, Current-Starved Oscillator, Time- Domain Quantization.