A Miniaturized 2.49-GHz Low-Phase-Noise Temperature-Stable SAW Oscillator

Abstract

In this letter, a 2.49-GHz temperature-stable oscillator is implemented using a temperature-compensated surface acoustic wave (TC-SAW) resonator. The cross-coupled topology is adopted to suppress power supply variations and enhance output swing. The TC-SAW with a temperature-compensated layer is used to improve the temperature stability of the oscillator. Measurement results show that the oscillator achieves a phase noise of 145 dBc/Hz@1 MHz offset with a figure of merit (FoM) of 215 dB. The oscillator consumes a dc power of 0.6 mW under a supply voltage of 1 V. Over a temperature range of $- 40~^{\circ }$ C to $85~^{\circ }$ C, the oscillator’s frequency drift is less than 248 ppm and within 90 ppm over a range of $- 40~^{\circ }$ C to $65~^{\circ }$ C.