A differential inverter-based switched-capacitor oscillator in 65 nm CMOS technology

Abstract

This paper presents a differential inverter-based switched-capacitor (SC) oscillator in 65 nm CMOS technology. The proposed SC oscillator is based on the continuous-time two-integrator oscillator, and the differential version is formed by the inverter-based pseudo-differential operational trans-conductance amplifier (OTA). By employing the inverter-based OTA in the SC oscillator, the power consumption can be reduced because inverters operate at the class-AB mode compared with traditional OTAs which operate at the class-A mode. The oscillating frequency can be tunable by changing the capacitor ratios. The SC oscillator can be applied as a frequency divider for the clock frequency, while it can be adopted as an oscillator at the lower frequency band which requires huge values of the inductor and the capacitor if the LC oscillator is employed. The oscillating frequency in this work is 4.2 MHz, the power consumption is 0.14 mW at a 0.7 V supply voltage, and the clock frequency for the switches is 100 MHz. Arrays of such oscillators may find use in analog image processing applications.