학술논문
A VCO-ADC Linearized by a Capacitive Frequency-to-Current Converter
Document Type
Periodical
Source
IEEE Transactions on Circuits and Systems II: Express Briefs IEEE Trans. Circuits Syst. II Circuits and Systems II: Express Briefs, IEEE Transactions on. 70(6):1841-1845 Jun, 2023
Subject
Language
ISSN
1549-7747
1558-3791
1558-3791
Abstract
In this brief we propose a technique to compensate the distortion of an open-loop VCO-based ADC. The VCO is linearized by placing an analog feedback loop based on a frequency-to-current converter which uses an asynchronous switched capacitor circuit. The feedback loop relies on the VCO gain to linearize the ADC without requiring additional amplifiers. This permits the use of a ring oscillator with small input range to efficiently encode a large signal. The proposed technique has been experimentally demonstrated in an audio ADC. The proof-of-concept chip was fabricated in 130nm CMOS and achieves 76.64 dBA of peak SNDR with a Dynamic Range of 90dB and a power consumption of 482 $\mu \text{W}$ in 20kHz.