Design of low-voltage wide tuning range CMOS multipass voltage-controlled ring oscillator

This paper presents an 0.8-V power supply multi-pass loop ring oscillator. The oscillator employs cross-coupled PMOS transistors to improve phase noise characteristic and multi-pass loop to obtain wide frequency tuning range. The coarse and fine controlled signals are also applied to lower the noise sensitivity of the oscillator. Simulations using TSMC 90 nm CMOS technology shows 394MHz to 4.4GHz frequency tuning range and -94.6dBc/Hz at 1MHz offset from 4.4GHz. The power consumption is 11.2mW.