Temperature And Supply Voltage Insensitive Relaxation Oscillator Using Voltage Reference

These days smart devices are developing rapidly and becoming smaller. This recent trend requires the on-chip oscillator to be smaller and more accurate. A relaxation oscillator, which occupies a small area and consumes low power, is the potential candidate. However, its operation is sensitive to temperature and the supply voltage. Therefore, solution for these issues is very important. In this paper, we design a small area on-chip current-mode relaxation oscillator, that is insensitive to temperature and supply voltage variation, using voltage reference. The operation frequency of the proposed oscillator is 3.01MHz. And the frequency variation is 2.39% when supply voltage change from 1.4V to 2.0V and 1.09% when temperature change from -20°C to 100°C with the supply voltage of 1.8V. This oscillator is designed and fabricated in 0.18μm CMOS process, and the oscillator consumes 40μW and occupies 0.0196mm
²
.