A method to provide a low-power clock signal or a low-noise clock signal is described herein. It is determined whether a low-power mode or a low-noise mode is in use. A voltage reference input of a low-dropout voltage regulator (LDO) is switched to a low-power voltage reference for low-power mode and to a low-noise voltage reference for low-noise mode. The LDO provides a constant voltage output to a crystal oscillator. A clock signal is generated using the crystal oscillator. The clock signal is limited using a low-power limiter to generate a low-power output clock signal and/or is limited using a low-noise limiter to generate a low-noise clock signal. The low-power output clock signal or the low-noise output clock signal is selected using a mux.