A temperature and voltage-insensitive ring oscillator

Ring oscillator is widely used in modern electronic systems due to its ease of implementation. However, its performance suffers severely from temperature and voltage variations. This paper presents a temperature and voltage-insensitive ring oscillator that is realized by incorporating negative feedback using a switched-capacitive resistor and near-zero temperature coefficient composite resistors. Implemented using a 0.18um CMOS process, the proposed design exhibits a frequency variation of 0.92% over a temperature range of -40°C to 125°C and a variation of 2.8% with supply voltage ranging from 1.2V to 2.1V. The results demonstrate the practicality of the proposed design for temperature and voltage-insensitive applications.