Variation-Tolerant Quick-Start-Up CMOS Crystal Oscillator With Chirp Injection and Negative Resistance Booster

Abstract

This paper presents a variation-tolerant quick-startup 39.25 MHz crystal oscillator and a theoretical analysis of a proposed chirp injector (CI) and negative resistance booster (NRB) for the quick start up. A new analysis of the theoretical minimum start-up time provides a new criterion for evaluating the start-up time in crystal oscillators. The calculated theoretical minimum start-up time at 39.25 MHz is 11.1 μs. Anew analysis of the proposed CI and NRB clarifies the validity of the universal optimum control method. It explains the reason why the proposed CI and NRB reduce the start-up time and its variation. The proposed crystal oscillator with the proposed CI and NRB exhibits a startup time of 158 μs at 39.25 MHz. The variation of the start-up time variations is ±13% over the supply voltage range of 1.2-1.8 V and ±7% over the temperature range of -30 to 125 °C. The power consumption of the crystal oscillator in the steady state is 181 μW with a phase noise of -147 dBc/Hz at 1 kHz offset frequency, which corresponds to a figure of merit (FoM) of 276 dB.