Performance Comparison of Oscillator Circuit Topology for MEMS SAW Resonator

Abstract

Abstract-This paper presents the simulation results and the performance comparison for three different pierce oscillator circuit topologies. The oscillators were based on the CMOS MEMS SAW resonator. The designs were simulated using 0.35um CMOS technology. Design_3 has the best phase noise performance and settling time as compared to the other two topologies namely Design_1 and Design_2. The settling time for Design_3 was 10ns and the phase noise performance was -90.3dBc/Hz at 10-kHz offset frequency. Design_2 required 40ns to achieve stability where the phase noise performance was -80.1dBc/Hz at 10-kHz offset frequency. Meanwhile, Design_1 required 30ns before it could achieve stability and the phase noise performance was -56.8dBc/Hz at 100-kHz offset frequency. Phase noise performance was the most important criteria for oscillator where in most cases, the resonator used in an oscillator must have high Q in order for the oscillator to have good phase noise performance. However, the sustaining amplifier circuit could also be used to improve the phase noise performance of the oscillator.